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Categories:
>>Components

Overall Game:
>>Retro style
>>800x600
>>Tile based

Player:
>>Animation
>>Arrow Key controls
>>Space bar to fire and bomb
>>Left/Right Ctrl for special Destroy-All bomb?
>>Mouse Controls?
>>Death & New Life sequence

Scrolling Terrain:
>>Scrolling Ground graphics
>>Scrolling Air graphics (clouds, smoke, etc.)

Ground Enemies:
>>AI
>>Death Sequence
>>Five Ground Enemies:
>>>Jeeps/Trucks (fast shoot & run)
>>>Tanks (slow, stay & shoot)
>>>Buildings (Non Moving. People on roof tops?)
>>>Bunkers/Fortresses (Non-moving. Shoot back and hard to kill)
>>>*Mech Unit (stay & shoot, can launch to become air unit).
*Optional if we have time

Air Enemies:
>>AI
>>Death Sequence
>>Five Air Enemies:
>>>Jets (shoot and run)
>>>Copters (stay and shoot)
>>>Kamakazis
>>>Harriers (combo Jet & Copter strategy)
>>>*Mech Unit (stay & shoot, can land to become ground unit)
*Optional if we have time

Bullets:
>>Player Air to Air Missiles
>>Player Bombs (or Air to Ground Missiles)
>>Enemy Air to Air Missiles
>>Enemy Surface to Air Missiles
>>Enemy Collision/Damage
>>Player Collision/Damage

Graphics:
>>Sprites
>>Player
>>Air Enemies
>>Ground Enemies
>>Player Missiles
>>Player Bombs
>>Enemy Missiles
>>Enemy SAMS
>>Explosions
>>GUI/HUD
>>Splash Screen
>>Menu
>>High Score Screen

If we have time:
Bosses:
>>AI
>>Enemy Launch
>>Missiles

sync on:hide mouse
set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)

type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
endtype

global player as ship
#CONSTANT BACKGROUND_IMAGE=5000
global background_scroll
global background_scroll_rate=2
set_player()

make_temp_background()




do
   cls
   draw_background()
   animate_player()
   draw_player()
   if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   endif

   sync
loop

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-37
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2),player.ypos+player.height,player.shadow
   set sprite priority 1,50
   set sprite priority 2,40
   set sprite alpha 2,80-player.height
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos
   if downkey()=1 then inc player.ypos
   if leftkey()=1 then dec player.xpos
   if rightkey()=1 then inc player.xpos
   if keystate(17)=1 then inc player.height
   if keystate(31)=1 then dec player.height

   if player.height<0 then player.height=0
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-37 then player.ypos=screen height()-37
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   ink rgb(210,240,210),0
   box 0,0,screen width(),screen height()
   lock pixels
   for a = 1 to 1000
      ink rgb(rnd(255),rnd(255),rnd(255)),1
      dot rnd(screen width()),rnd(screen height())
   next a
   unlock pixels
   get image BACKGROUND_IMAGE,0,0,screen width(),screen height(),1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()

   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height then dec background_scroll,screen height()
endfunction

if spacekey()=1 and timer()>player.next_fire then add_missile(4):add_missile(16)

REM Project: SpriteFun
REM Created: 12/25/2006 11:15:28 AM
REM
REM ***** Main Source File *****
REM
makesprite(1,255,127,63,32,32)
show sprite 1

hide mouse

do
sprite 1,mousex(),mousey(),1
show sprite 1
  if mouseclick()=1
    for splash=1 to 99
      makesprite(splash,rnd(255),rnd(255),rnd(255),rnd(48)+16,rnd(48)+16)
      show sprite splash
    next splash
  endif
loop

function makesprite(num as integer,R as integer, G as integer, B as integer, xsize as integer, ysize as integer)

   create bitmap 1,xsize+8,ysize+8
   ink rgb(255,255,255),0
   box 0,0,xsize+4,ysize+4
   get image 999,1,1,xsize,2,1
   sprite 999,0,0,999
   hide sprite 999
   box 1,1,xsize,ysize,rgb(R,G,B),rgb(R/3,G/3,B/3),rgb(R,G,B),rgb(R/3,G/3,B/3)
   set sprite alpha 999,222
   paste sprite 999,1,1
   set sprite alpha 999,182
   paste sprite 999,1,2
   set sprite alpha 999,142
   paste sprite 999,1,3
   set sprite alpha 999,102
   paste sprite 999,1,4
   set sprite alpha 999,62
   paste sprite 999,1,5
   ink rgb(22,22,22),0:line 1,1,xsize,1:line 1,1,1,ysize:line xsize,1,xsize,ysize:line 1,ysize,xsize,ysize:dot xsize,ysize
   dot 2,2:dot 2,ysize-1:dot xsize-1,2:dot xsize-1,ysize-1
   ink rgb(0,0,0),0:dot 1,1:dot 1,2:dot 2,1:dot xsize-1,1:dot xsize,1:dot xsize,2:dot 1,ysize-1:dot 1,ysize:dot 2,ysize:dot xsize-1,ysize:dot xsize,ysize:dot xsize,ysize-1
   get image num,1,1,xsize+1,ysize+1,1
   sprite num,rnd(screen width()-xsize),rnd(screen height()-ysize),num
   hide sprite 1
   delete bitmap 1

   set current bitmap 0

endfunction

sync on:hide mouse
set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
load image "uibar.bmp",5001

type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
endtype

global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=.3
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=.35
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=.3


set_player()

make_temp_background()




do
   cls
   draw_background()
   animate_player()
   draw_player()
   if array count(player_missile())>=0 then draw_missiles()
   if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   endif


   sync
loop

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2),player.ypos+player.height,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos
   if downkey()=1 then inc player.ypos
   if leftkey()=1 then dec player.xpos
   if rightkey()=1 then inc player.xpos
   if keystate(17)=1 then inc player.height
   if keystate(31)=1 then dec player.height
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<0 then player.height=0
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16 then kill_missile(a)
   next a
endfunction

function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction



function free_sprite()
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

sync on:hide mouse
set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
load image "uibar.bmp",5001

type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
endtype

global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=.3
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=.35
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=.3


set_player()

make_temp_background()




do
   cls
   draw_background()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   endif



   sync
loop

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
   player.gun_strength=1
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2),player.ypos+player.height,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos
   if downkey()=1 then inc player.ypos
   if leftkey()=1 then dec player.xpos
   if rightkey()=1 then inc player.xpos
   if keystate(17)=1 then inc player.height
   if keystate(31)=1 then dec player.height
   if spacekey()=1 and timer()>player.next_fire
      select player.gun_strength
         case 1:add_missile(8):endcase
         case 2:add_missile(4):add_missile(12):endcase
         case 3:add_missile(0):add_missile(8):add_missile(16):endcase
      endselect
   endif

   if player.height<0 then player.height=0
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16 then kill_missile(a)
   next a
endfunction

function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction



function free_sprite()
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

`temporary function to test added features

function test_features()
 if inkey$()="p" then player.start_frame=6:player.end_frame=8
 if inkey$()="o" then player.start_frame=1:player.end_frame=4
 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
endfunction

sync on:hide mouse
set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
load image "uibar.bmp",5001
load image "building1.bmp",6000

type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   sprite_number as integer
endtype

global player as ship
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
global distance_travelled as float
background_scroll_rate=.3
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=.35
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=.3


set_player()

make_temp_background()

add_doodad(32,100,6000)
add_doodad(320,150,6000)
add_doodad(352,150,6000)




do
   cls
   draw_background()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   endif



   sync
loop

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
   player.gun_strength=1
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2),player.ypos+player.height,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos
   if downkey()=1 then inc player.ypos
   if leftkey()=1 then dec player.xpos
   if rightkey()=1 then inc player.xpos
   if keystate(17)=1 then inc player.height
   if keystate(31)=1 then dec player.height
   if spacekey()=1 and timer()>player.next_fire
      select player.gun_strength
         case 1:add_missile(8):endcase
         case 2:add_missile(4):add_missile(12):endcase
         case 3:add_missile(0):add_missile(8):add_missile(16):endcase
      endselect
   endif

   if player.height<0 then player.height=0
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   inc distance_travelled,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16 then kill_missile(a)
   next a
endfunction

function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction



function free_sprite()
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

`temporary function to test added features

function test_features()
 if inkey$()="p" then player.start_frame=6:player.end_frame=8
 if inkey$()="o" then player.start_frame=1:player.end_frame=4
 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   array delete element perm_object_tile(),count
endfunction

if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,6000)
   endif

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
load image "uibar.bmp",5001
load image "building1.png",6000

type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   sprite_number as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)




do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,6000)
   endif
   draw_background()
   scroll_tiles()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(17)=1 then inc player.height,1
   if keystate(31)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16 then kill_missile(a)
   next a
endfunction

function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()
 if inkey$()="p" then player.start_frame=6:player.end_frame=8
 if inkey$()="o" then player.start_frame=1:player.end_frame=4
 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   sprite_number as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)



loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,6000)
   endif
   draw_background()
   scroll_tiles()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            kill_doodad(a)

            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()
 if inkey$()="p" then player.start_frame=6:player.end_frame=8
 if inkey$()="o" then player.start_frame=1:player.end_frame=4
 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,12,6000)
   endif
   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            kill_doodad(a)

            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
   shadow as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,rnd(24)+6,6000)
   endif
   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            kill_doodad(a)

            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Priority perm_object_tile(count).sprite_number,perm_object_tile(count).height
   perm_object_tile(count).shadow=free_sprite()
   Sprite perm_object_tile(count).shadow,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Diffuse perm_object_tile(count).shadow,0,0,0
   Set Sprite Alpha perm_object_tile(count).shadow,50
   Set Sprite Priority perm_object_tile(count).shadow,perm_object_tile(count).height-1
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      h=perm_object_tile(a).height
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).sprite_number,85+h
      sprite perm_object_tile(a).shadow,perm_object_tile(a).xpos+4,perm_object_tile(a).ypos+4,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).shadow,85+h*2
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   if sprite exist(perm_object_tile(count).shadow)=1 then delete sprite perm_object_tile(count).shadow
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
disect("numbers.bmp",10,1,30)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1

for a = 10 to 16
   sprite a,-100,-100,19
next a


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
   shadow as integer
   points as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
global SCORE
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,rnd(24)+6,100,6000)
   endif
   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
   score$=str$(score)
   for a = len(score$) to 1 step -1
      value=val(mid$(score$,a))
      if value=0 then value=10
      sprite 10+a,700-((len(score$)-a)*16),540,29+value
      set sprite priority 10+a,110
   next a
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            inc score,perm_object_tile(a).points
            kill_doodad(a)


            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).points,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,points,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).points=points
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Priority perm_object_tile(count).sprite_number,perm_object_tile(count).height
   perm_object_tile(count).shadow=free_sprite()
   Sprite perm_object_tile(count).shadow,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Diffuse perm_object_tile(count).shadow,0,0,0
   Set Sprite Alpha perm_object_tile(count).shadow,50
   Set Sprite Priority perm_object_tile(count).shadow,perm_object_tile(count).height-1
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      h=perm_object_tile(a).height
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).sprite_number,85+h
      sprite perm_object_tile(a).shadow,perm_object_tile(a).xpos+4,perm_object_tile(a).ypos+4,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).shadow,85+h*2
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   if sprite exist(perm_object_tile(count).shadow)=1 then delete sprite perm_object_tile(count).shadow
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
disect("numbers.bmp",10,1,30)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1

for a = 8 to 15
   sprite a,-100,-100,19
next a


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  y as float
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
   shadow as integer
   points as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=1
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=1
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
global SCORE
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls
   if rnd(500)<=10
      make_new_object(rnd(Screen Width()-34),-32,rnd(24)+6,100,6000)
   endif
   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      Paste sprite SpriteID,(column-1)*64-13,tile(column,row).y
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
   score$=str$(score)
   for a = len(score$) to 1 step -1
      value=val(mid$(score$,a))
      if value=0 then value=10
      sprite 8+a,751-((len(score$)-a)*16),554,29+value
      set sprite priority 8+a,110
   next a
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            inc score,perm_object_tile(a).points
            kill_doodad(a)


            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).points,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,points,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).points=points
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Priority perm_object_tile(count).sprite_number,perm_object_tile(count).height
   perm_object_tile(count).shadow=free_sprite()
   Sprite perm_object_tile(count).shadow,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Diffuse perm_object_tile(count).shadow,0,0,0
   Set Sprite Alpha perm_object_tile(count).shadow,50
   Set Sprite Priority perm_object_tile(count).shadow,perm_object_tile(count).height-1
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      h=perm_object_tile(a).height
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).sprite_number,85+h
      sprite perm_object_tile(a).shadow,perm_object_tile(a).xpos+4,perm_object_tile(a).ypos+4,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).shadow,85+h*2
      inc perm_object_tile(a).ypos,background_scroll_rate
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   if sprite exist(perm_object_tile(count).shadow)=1 then delete sprite perm_object_tile(count).shadow
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction

t0,t1,t2,d1,

t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,
t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t0,d1,d1,d1,d1,d1,t0,d1,d1,d1,d1,d1,t0,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t1,d1,d1,d1,d1,d1,t0,d1,d1,d1,d1,d1,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,d1,d1,d1,d1,d1,t0,d1,d1,d1,d1,d1,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t0,t0,t1,t0,t0,t0,t1,t0,t0,t0,t1,t0,t0,
t0,t0,t1,t0,t0,t0,t1,t0,t0,t0,t1,t0,t0,
d1,t0,t1,t0,t0,t0,t1,t0,t0,t0,t1,t0,d1,
t0,t0,t1,t0,t0,t0,t2,t0,t0,t0,t1,t0,t0,
d1,t0,t1,t0,t0,t0,t1,t0,t0,t0,t1,t0,d1,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
d1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,d1,
t0,t0,t1,d1,t0,t0,t2,t0,t0,d1,t1,t0,t0,
t0,t0,t1,d1,t0,t0,t1,t0,t0,d1,t1,t0,t0,
t0,t0,t1,d1,t0,t0,t2,t0,t0,d1,t1,t0,t0,
t0,t0,t1,d1,t0,t0,t1,t0,t0,d1,t1,t0,t0,
t0,t0,t1,d1,t0,t0,t2,t0,t0,d1,t1,t0,t0,
t0,t0,t0,t0,t0,t1,t1,t1,t0,t0,t0,t0,t0,
t0,d1,d1,t0,t0,t1,t2,t1,t0,t0,d1,d1,t0,
t0,d1,d1,t0,t0,t1,t1,t1,t0,t0,d1,d1,t0,
t0,d1,d1,t0,t0,t0,t0,t0,t0,t0,d1,d1,t0,
t0,t0,t0,t0,d1,d1,d1,d1,d1,t0,t0,t0,t0,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t0,t0,t0,t0,d1,d1,d1,d1,d1,t0,t0,t0,t0,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t0,t0,t0,t0,t0,t1,t1,t1,t0,t0,t0,t0,t0,
t0,t0,d1,t0,t0,t1,t2,t1,t0,t0,d1,t0,t0,
t0,t0,t0,t0,t0,t1,t1,t1,t0,t0,t0,t0,t0,
t1,t0,t0,t0,t0,t1,t1,t1,t0,t0,t0,t0,t1,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t0,d1,d1,t0,t0,t0,t0,t0,t0,t0,d1,d1,t0,
t0,d1,d1,t0,t0,t0,t0,t0,t0,t0,d1,d1,t0,
t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,
t1,t0,t0,t0,t0,t1,t1,t1,t0,t0,t0,t0,t1,
t1,t0,t0,t0,t0,d1,d1,d1,t0,t0,t0,t0,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,t1,t0,t0,t1,t1,t1,t1,t1,t0,t0,t1,t1,
t1,t0,t0,t0,t1,t2,t2,t2,t1,t0,t0,t1,t1,
t1,t0,t0,t0,t1,t1,t1,t1,t1,t0,t0,t1,t1,
t1,t0,d1,t0,t0,t0,t0,t0,t0,t0,d1,t0,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t0,t1,
t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,
t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,t1,

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
disect("numbers.bmp",10,1,30)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1

for a = 8 to 15
   sprite a,-100,-100,19
next a


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  imagename as string
  y as float
  occupied as integer
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
   shadow as integer
   points as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=0.6
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=0.6
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
global SCORE
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls

   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
        tile(column,row).imagename=image$
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      `imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      if tile(column,row).y>-64 and tile(column,row).y<screen height()-64
        Paste sprite SpriteID,(column-1)*64-32,tile(column,row).y
        if left$(tile(column,row).imagename,1)="d" and tile(column,row).occupied=0
          tile(column,row).occupied=1
          make_new_object((column-1)*64-16,tile(column,row).y+16,rnd(24)+6,100,6000)
        endif
      endif
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
   score$=str$(score)
   for a = len(score$) to 1 step -1
      value=val(mid$(score$,a))
      if value=0 then value=10
      sprite 8+a,751-((len(score$)-a)*16),554,29+value
      set sprite priority 8+a,110
   next a
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            inc score,perm_object_tile(a).points
            kill_doodad(a)


            exitfunction
         endif
      next a
endfunction


function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).points,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,points,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).points=points
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Priority perm_object_tile(count).sprite_number,perm_object_tile(count).height
   perm_object_tile(count).shadow=free_sprite()
   Sprite perm_object_tile(count).shadow,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Diffuse perm_object_tile(count).shadow,0,0,0
   Set Sprite Alpha perm_object_tile(count).shadow,50
   Set Sprite Priority perm_object_tile(count).shadow,perm_object_tile(count).height-1
endfunction

function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      h=perm_object_tile(a).height
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).sprite_number,85+h
      sprite perm_object_tile(a).shadow,perm_object_tile(a).xpos+4,perm_object_tile(a).ypos+4,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).shadow,85+h*2
      inc perm_object_tile(a).ypos,tilespeed#
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   if sprite exist(perm_object_tile(count).shadow)=1 then delete sprite perm_object_tile(count).shadow
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction

sync on:sync rate 0:hide mouse
`set display mode 800,600,32

set image colorkey 255,0,255
disect("player ship.bmp",4,2,1)
disect("player weapons.bmp",5,4,10)
disect("explosion32.png",16,1,50)
disect("numbers.bmp",10,1,30)
load image "uibar.bmp",5001
load image "building1.bmp",6000
load music "ng1975.mp3",1

for a = 8 to 15
   sprite a,-100,-100,19
next a


type ship
   xpos as integer
   ypos as integer
   height as integer
   animation_time as integer
   animation_step as integer
   animation_frame as integer
   start_frame as integer
   end_frame as integer
   next_move as integer
   shadow as integer
   next_fire as integer
   fire_speed as integer
   sprite_number as integer
   shadow_number as integer
   gun_strength as integer
   vulnerable as integer
endtype

type tile
  spritenumber as integer
  imagetype as integer
  imagename as string
  y as float
  occupied as integer
endtype

type tileimage
  imagenumber as integer
  imagetype as string
  spriteID as integer
endtype

type doodad
   xpos as integer
   image as integer
   ypos as float
   height as integer
   sprite_number as integer
   shadow as integer
   points as integer
endtype

type effect
   xpos as integer
   ypos as integer
   frame as integer
   start_frame as integer
   end_frame as integer
   next_frame as integer
   sprite_number as integer
endtype

type bullettype
  active as integer
  spritenumber as integer
  xpos as float
  ypos as float
  angle as float
endtype

dim explosion(-1) as effect
dim object_tile(-1) as doodad
dim perm_object_tile(-1) as doodad
global player as ship
dim player_missile(-1) as ship
#CONSTANT BACKGROUND_IMAGE=5000
#CONSTANT CLOUD_IMAGE=5002
#CONSTANT TREES_IMAGE=5003
global background_scroll as float
global background_scroll_rate as float
background_scroll_rate=0.6
global cloud_scroll as float
global cloud_scroll_rate as float
cloud_scroll_rate=1.22
global tree_scroll as float
global tree_scroll_rate as float
tree_scroll_rate=0.6
level=1
global spriteseed
spriteseed=10
global numberofrows
global tilespeed#
global SCORE
tilespeed#=1 `best to keep this as an integer, as it represents the number of pixels to scroll each loop

global numberofbullets as integer
global bulletimage as integer
global bulletspeed# as float
bulletspeed#=2

make_bullet()

set_player()

make_temp_background()

load_level(level)


player.vulnerable=timer()+2000
loop music 1
do
   `display fps - update once every 10 loops to reduce hit
   fps=screen fps()
   inc textcounter
   if textcounter=10 then textcounter=0
   if textcounter=0 then text_sprite(2000,0,0,str$(fps))

   cls

   draw_background()
   scroll_tiles()
   player_state()
   if array count(object_tile())>=0 then scroll_doodads()
   if array count(perm_object_tile())>=0 then scroll_perm_doodads()
   if array count(explosion())>=0 then draw_explosions()
   animate_player()
   draw_player()
   test_features()
   if array count(player_missile())>=0 then draw_missiles()
   `if timer()>player.next_move
      controls()
      player.next_move=timer()+3
   `endif
   doodad_attack()
   move_bullets()


   sync
loop

function text_sprite(entity,x,y,text$)
if text$="" then text$=" "
If Bitmap Exist(2)=0
   create bitmap 2,screen width()/2,screen height()/8
Else
   Set Current Bitmap 2
   cls
Endif
ink rgb(1,250,1),0
set text size 14
set text font "Arial"
text 0,0,text$
if image exist(entity) then delete image entity
if sprite exist(entity) then delete sprite entity
get image entity,0,0,text width(text$),text height(text$),1
sprite entity,x,y,entity
set sprite entity,0,0
set sprite priority entity,300
Set Current Bitmap 0
`endif
endfunction



function load_level(level)

  `The level is made up of tiles.  Each tile is a 64x64 sprite, and has a sprite number
  `which links to the array 'tile(column,row).spritenumber'.

  `Each sprite also has an image identifier, which is made of two characters, stored
  `in 'tile(column,row).imagetype'.

  `for example, if it has the tile image "t2.png", then the identifier is tile(column,row)="t2"

  `The level file "level1.txt", where the '1' can be any level number is a text file with the following format:
  `1st line is a header, and contains the names of all the images it need to load
  `All other lines represent the tiles' column, row and image.  If it is 't0' it is an empty space.
  `A comma is used to separate tiles - including a comma at the end of each row.


  open to read 1,"level"+str$(level)+".txt"
  `Read header. The header contains the image types used in the level
  read string 1,header$
  numberoftileimages=len(header$)/3
  dim tileimage(numberoftileimages) as tileimage
  for n=1 to numberoftileimages
      chunk=n*3
      image$=left$(right$(left$(header$,chunk),3),2) `parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tileimage(n).imagenumber=free_image()
        tileimage(n).spriteID=free_sprite()
        tileimage(n).imagetype=image$
        load image image$+".png",tileimage(n).imagenumber,1
        sprite tileimage(n).spriteID,-100,-100,tileimage(n).imagenumber
      endif
  next n

  row=0
  repeat
    `scan through each subsequent row of the text file to get tile type and position
    inc row
    numberofrows=row
    dim tile(13,row) as tile
    read string 1,string$
    `scan through each column of the text file
    for column=1 to 13 `there are 13 columns, made up of 3 characters each (2 letters and a comma)
      chunk=column*3
      image$=left$(right$(left$(string$,chunk),3),2) `Parse the string: this takes the left 2 characters (to get rid of the comma) of the right 3 (ie. the end bit) of the left 'chunk' (the chunk is increased in steps of 3)
      if image$<>"" and image$<>"t0"
        tile(column,row).spritenumber=free_sprite()
        image=0
        for n=1 to numberoftileimages
          if image$=tileimage(n).imagetype
            imagenumber=tileimage(n).imagenumber
            image=n
            Exit
          Endif
        next n
        `as we don't know how big the level is until this loop has finished, we don't know where to position the tiles yet,
        `so we'll put them at 0,0 for the time being
        `sprite tile(column,row).spritenumber,0,0,imagenumber
        tile(column,row).imagetype=image
        tile(column,row).imagename=image$
      endif
    next column$
  until file end(1)=1

  `go through tiles again.  This time, now that we know the total number of rows, we can position the tiles correctly
  for column=1 to 13
    for row=1 to numberofrows
      `if there is a tile at that coordinate
      if (tile(column,row).spritenumber)>0
        tile(column,row).y=(row-1)*64-(numberofrows*64)+(9*64)
        `sprite tile(column,row).spritenumber,(column-1)*64-13,tile(column,row).y,sprite image(tile(column,row).spritenumber)
        `set sprite tile(column,row).spritenumber,1,0
      endif
    next row
  next column

endfunction

function scroll_tiles()

for row=1 to numberofrows
  for column=1 to 13
    spriteID=tileimage(tile(column,row).imagetype).spriteID
    if spriteID>0
      `imageID=tileimage(tile(column,row).imagetype).imagenumber
      tile(column,row).y=tile(column,row).y+tilespeed#
      if tile(column,row).y>-64 and tile(column,row).y<screen height()-64
        Paste sprite SpriteID,(column-1)*64-32,tile(column,row).y
        if left$(tile(column,row).imagename,1)="d" and tile(column,row).occupied=0
          tile(column,row).occupied=1
          make_new_object((column-1)*64-16,tile(column,row).y+16,rnd(24)+6,100,6000)
        endif
      endif
    endif
  next column
next row

endfunction

function set_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.height =10
   player.animation_step=50
   player.animation_time=timer()+player.animation_step
   player.animation_frame=1
   player.start_frame=1
   player.end_frame=4
   player.next_move=timer()+3
   player.shadow=5
   player.next_fire=timer()
   player.fire_speed=500
endfunction

function animate_player()
   if timer()>player.animation_time
      inc player.animation_frame
      if player.animation_frame>player.end_frame then player.animation_frame=player.start_frame
      player.animation_time=timer()+player.animation_step
   endif
endfunction



function draw_player()
   sprite 1,player.xpos,player.ypos,player.animation_frame
   sprite 2,player.xpos+(player.height/2)+2,player.ypos+player.height+2,player.shadow
   set sprite priority 1,5+player.height
   set sprite priority 2,4+player.height
   set sprite alpha 2,80-player.height
   scale sprite 1,85+player.height/2
   scale sprite 2,85+player.height/1.5
   if sprite collision(1,0)>2 then check_player_collision()
endfunction

function disect(filename as string,across,down,imagestart)

   load bitmap filename,1
   x=bitmap width(1)/across
   y=bitmap height(1)/down
   for a = 0 to down-1
   for b = 0 to across-1
   get image imagestart+a*across+b,x*b,y*a,x*b+x,y*a+y
   next b:next a
   delete bitmap 1
endfunction

function controls()
   if upkey()=1 then dec player.ypos,2
   if downkey()=1 then inc player.ypos,2
   if leftkey()=1 then dec player.xpos,2
   if rightkey()=1 then inc player.xpos,2
   if keystate(31)=1 then inc player.height,1
   if keystate(17)=1 then dec player.height,1
   if spacekey()=1 and timer()>player.next_fire then add_missile(8)

   if player.height<6 then player.height=6
   if player.height>30 then player.height=30
   if player.xpos<5 then player.xpos=5
   if player.xpos>screen width()-37 then player.xpos=screen width()-37
   if player.ypos>screen height()-115 then player.ypos=screen height()-115
   if player.ypos<128 then player.ypos=128
endfunction

function make_temp_background()
   load image "BackGround.png",BACKGROUND_IMAGE,1
   load image "Clouds.png",CLOUD_IMAGE,1
   load image "Trees.png",TREES_IMAGE,1
endfunction

function draw_background()
   paste image BACKGROUND_IMAGE,0,background_scroll
   paste image BACKGROUND_IMAGE,0,background_scroll+screen height()*2
   inc background_scroll,background_scroll_rate
   if background_scroll>screen_height*2 then dec background_scroll,screen height()*2

   paste image TREES_IMAGE,0,tree_scroll,1
   paste image TREES_IMAGE,0,tree_scroll+screen height()*1.5,1
   inc tree_scroll,tree_scroll_rate
   if tree_scroll>screen_height*1.5 then dec tree_scroll,screen height()*1.5

   sprite CLOUD_IMAGE,0,cloud_scroll,CLOUD_IMAGE
   sprite CLOUD_IMAGE+1,0,cloud_scroll+screen height()*1.5,CLOUD_IMAGE
   set sprite priority CLOUD_IMAGE,30
   set sprite priority CLOUD_IMAGE+1,30
   inc cloud_scroll,cloud_scroll_rate
   if cloud_scroll>screen_height*1.5 then dec cloud_scroll,screen height()*1.5

   sprite 3,0,522,5001
   set sprite 3,0,1
   set sprite priority 3,100
   score$=str$(score)
   for a = len(score$) to 1 step -1
      value=val(mid$(score$,a))
      if value=0 then value=10
      sprite 8+a,751-((len(score$)-a)*16),554,29+value
      set sprite priority 8+a,110
   next a
endfunction

function add_missile(offset)
   array insert at top player_missile()
   player_missile(0).xpos=player.xpos+offset
   player_missile(0).ypos=player.ypos-16
   player_missile(0).height=player.height
   player_missile(0).start_frame=10
   player_missile(0).end_frame=13
   player_missile(0).animation_step=50
   player_missile(0).animation_time=timer()+50
   player_missile(0).animation_frame=10
   player_missile(0).shadow=14
   player_missile(0).sprite_number=free_sprite()
   sprite player_missile(0).sprite_number,player_missile(0).xpos,player_missile(0).ypos,player_missile(0).animation_frame
   player_missile(0).shadow_number=free_sprite()
   sprite player_missile(0).shadow_number,player_missile(0).xpos+(player_missile(0).height/2),player_missile(0).ypos+player_missile(0).height,player_missile(0).shadow
   set sprite alpha player_missile(0).shadow_number,80-player_missile(0).height
   set sprite priority player_missile(0).sprite_number,50
   set sprite priority player_missile(0).shadow_number,40
   player.next_fire=timer()+player.fire_speed
endfunction

function draw_missiles()
   for a = array count(player_missile()) to 0 step -1
      dec player_missile(a).ypos,3
      if timer()>player_missile(a).animation_time
         inc player_missile(a).animation_frame
         if player_missile(a).animation_frame>player_missile(a).end_frame then player_missile(a).animation_frame=player_missile(a).start_frame
         player_missile(a).animation_time=timer()+player_missile(a).animation_step
      endif
      sprite player_missile(a).sprite_number,player_missile(a).xpos,player_missile(a).ypos,player_missile(a).animation_frame
      sprite player_missile(a).shadow_number,player_missile(a).xpos+(player_missile(a).height/2),player_missile(a).ypos+player_missile(a).height,player_missile(a).shadow
      set sprite alpha player_missile(a).shadow_number,80-player_missile(a).height
      set sprite priority player_missile(a).sprite_number,player_missile(a).height+5
      set sprite priority player_missile(a).shadow_number,player_missile(a).height+4
      if player_missile(a).ypos<-16
         kill_missile(a)
      else
         if array count(perm_object_tile())>=0 then check_shot_object_collision(a)
      endif

   next a
endfunction

function check_shot_object_collision(count)
  hit=sprite collision(player_missile(count).sprite_number,0)
      if hit=0 then exitfunction
      for a = array count(perm_object_tile()) to 0 step -1
         if sprite collision(player_missile(count).sprite_number,perm_object_tile(a).sprite_number)=1 and  player_missile(count).height<=perm_object_tile(a).height
            add_explosion(player_missile(count).xpos-8,player_missile(count).ypos-8)
            kill_missile(count)
            inc score,perm_object_tile(a).points
            kill_doodad(a)


            exitfunction
         endif
      next a
endfunction

function doodad_attack()

count=array count(perm_object_tile())
for n=1 to count
  if rnd(100)=0 then fire_bullet(perm_object_tile(n).xpos,perm_object_tile(n).ypos,rnd(360))
next n

endfunction

function make_bullet()

bulletimage=free_image()
load image "bullet.png",bulletimage,1

endfunction

function fire_bullet(startx,starty,angle)

inc numberofbullets
bulletnumber=numberofbullets
dim bullet(numberofbullets) as bullettype
bullet(bulletnumber).spritenumber=free_sprite()
sprite bullet(bulletnumber).spritenumber,startx,starty,bulletimage
offset sprite bullet(bulletnumber).spritenumber,sprite width(bullet(bulletnumber).spritenumber)/2,sprite height(bullet(bulletnumber).spritenumber)/2
rotate sprite bullet(bulletnumber).spritenumber,angle
bullet(bulletnumber).active=1
bullet(bulletnumber).xpos=startx
bullet(bulletnumber).ypos=starty
bullet(bulletnumber).angle=angle


endfunction

function move_bullets()

for bulletnumber=1 to numberofbullets
  if bullet(bulletnumber).active=1
    inc bullet(bulletnumber).xpos,bulletspeed#*sin(bullet(bulletnumber).angle)
    inc bullet(bulletnumber).ypos,bulletspeed#*cos(bullet(bulletnumber).angle)
    inc bullet(bulletnumber).ypos,tilespeed#
    sprite bullet(bulletnumber).spritenumber,bullet(bulletnumber).xpos,bullet(bulletnumber).ypos,bulletimage
    if bullet(bulletnumber).ypos>screen height() or bullet(bulletnumber).ypos<0 or bullet(bulletnumber).xpos>screen width() or bullet(bulletnumber).xpos<0
      delete sprite bullet(bulletnumber).spritenumber
      bullet(bulletnumber).active=0
    endif
  endif
next bulletnumber

endfunction



function kill_missile(count)
   delete sprite player_missile(count).sprite_number
   delete sprite player_missile(count).shadow_number
   array delete element player_missile(),count
endfunction

`temporary function to test added features

function test_features()

 if inkey$()="1" then player.gun_strength=1
 if inkey$()="2" then player.gun_strength=2
 if inkey$()="3" then player.gun_strength=3
 if inkey$()="=" then add_explosion(rnd(screen width()),rnd(screen height())):add_explosion(rnd(screen width()),rnd(screen height()))
endfunction

function add_doodad(xpos,ypos,image)
   array insert at bottom object_tile()
   count=array count(object_tile())
   object_tile(count).xpos=xpos
   object_tile(count).ypos=ypos
   object_tile(count).image=image
endfunction

function scroll_doodads()
   for a = array count(object_tile()) to 0 step -1
      if object_tile(a).ypos<=DISTANCE_TRAVELLED-32
          make_new_object(object_tile(a).xpos,object_tile(a).ypos-DISTANCE_TRAVELLED-32,object_tile(a).height,object_tile(a).points,object_tile(a).image)
          array delete element object_tile(),a
      endif
   next a
endfunction

function make_new_object(xpos,ypos,height,points,image)
   array insert at bottom perm_object_tile()
   count=array count(perm_object_tile())
   perm_object_tile(count).xpos=xpos
   perm_object_tile(count).ypos=ypos
   perm_object_tile(count).image=image
   perm_object_tile(count).height=height
   perm_object_tile(count).points=points
   perm_object_tile(count).sprite_number=free_sprite()
   sprite perm_object_tile(count).sprite_number,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Priority perm_object_tile(count).sprite_number,perm_object_tile(count).height
   perm_object_tile(count).shadow=free_sprite()
   Sprite perm_object_tile(count).shadow,perm_object_tile(count).xpos,perm_object_tile(count).ypos,perm_object_tile(count).image
   Set Sprite Diffuse perm_object_tile(count).shadow,0,0,0
   Set Sprite Alpha perm_object_tile(count).shadow,50
   Set Sprite Priority perm_object_tile(count).shadow,perm_object_tile(count).height-1
endfunction



function scroll_perm_doodads()
   for a = array count(perm_object_tile()) to 0 step -1
      h=perm_object_tile(a).height
      sprite perm_object_tile(a).sprite_number,perm_object_tile(a).xpos,perm_object_tile(a).ypos,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).sprite_number,85+h
      sprite perm_object_tile(a).shadow,perm_object_tile(a).xpos+4,perm_object_tile(a).ypos+4,perm_object_tile(a).image
      Scale Sprite perm_object_tile(a).shadow,85+h*2
      inc perm_object_tile(a).ypos,tilespeed#
      if perm_object_tile(a).ypos>screen height() then kill_doodad(a)
   next a
endfunction

function kill_doodad(count)
   if sprite exist(perm_object_tile(count).sprite_number)=1 then delete sprite perm_object_tile(count).sprite_number
   if sprite exist(perm_object_tile(count).shadow)=1 then delete sprite perm_object_tile(count).shadow
   array delete element perm_object_tile(),count
endfunction

function free_sprite()
count=spriteseed
   repeat
      inc count
   until sprite exist(count)=0
endfunction count

function free_image()
   repeat
      inc count
   until image exist(count)=0
endfunction count

function add_explosion(xpos,ypos)
   array insert at bottom explosion()
   count=array count(explosion())
   explosion(count).xpos=xpos
   explosion(count).ypos=ypos
   explosion(count).frame=50
   explosion(count).start_frame=50
   explosion(count).end_frame=65
   explosion(count).next_frame=timer()+50
   explosion(count).sprite_number=free_sprite()
   sprite explosion(count).sprite_number,explosion(count).xpos,explosion(count).ypos,explosion(count).frame
endfunction

function draw_explosions()
   for a = array count(explosion()) to 0 step -1
      if timer()>explosion(a).next_frame
         inc explosion(a).frame
         explosion(a).next_frame=timer()+50
      endif
      sprite explosion(a).sprite_number,explosion(a).xpos,explosion(a).ypos,explosion(a).frame
      if explosion(a).frame>=explosion(a).end_frame then kill_explosion(a)
   next a
endfunction

function kill_explosion(count)
   if sprite exist(explosion(count).sprite_number) then delete sprite explosion(count).sprite_number
   array delete element explosion(),count
endfunction

function check_player_collision()
   if player.vulnerable<=timer()
      if array count(perm_object_tile())>=0
         for a = array count(perm_object_tile()) to 0 step -1
            if player.height<=perm_object_tile(a).height
               if sprite collision(1,perm_object_tile(a).sprite_number)=1
                  kill_doodad(a)
                  add_explosion(player.xpos,player.ypos)
                  kill_player()
                  exitfunction
               endif
            endif
         next a
      endif
   endif
endfunction

function player_state()
   if player.vulnerable>timer()
      player.start_frame=6:player.end_frame=8
   else
      player.start_frame=1:player.end_frame=4
   endif
endfunction

function kill_player()
   player.xpos=(screen width()-32)/2
   player.ypos= screen height()-115
   player.vulnerable=timer()+3000
endfunction