Flickering Screen after integrating Sprites

Author

Message

DBProUser

15

Years of Service

User Offline

Joined: 28th Oct 2010

Location:

Posted: 22nd Nov 2010 17:57 Edited at: 22nd Nov 2010 17:59

Link

Hallo,

i have made a little 2D Game and it work really fine.

But now i wanted to put some Specials in it. I Thought about the Hero is throwing a Stone, to get Bananas from a Ape on a tree

After inserting some code, i get The Stone flying, but the Screen is terribly flickering that i get a headache. The Screen is flickering because it is changing very fast between the 3D-Blue-Background and my 2D-Animated Background. It just Stops Flickering after i throw a Stone, and Sometimes when the Monkey is Jumping (So i guess it has something to do with redrawing the Screen, but i dont Know how to do that, after trying so many variants without a Success)

So sorry for annoying you, but it would be great if i can find a Solution with your help.

Here is a Code Snippet

+ Code Snippet

Function MoveHero()

If Leftkey() = 1 Then HeroX = HeroX - HeroStep
if HeroX < 10 Then HeroX = 10

If Rightkey() = 1 Then HeroX = HeroX + HeroStep
if HeroX > 600 Then HeroX = 600
Paste Image 11, HeroX, 430, 1

ThrowStone()

Endfunction


Function ThrowStone()
Load Bitmap "Graphics/Stone.png", 3
Get Image 15, 0, 0, 25, 25, 1
Set Current Bitmap 0

StoneX# = HeroX
StoneY = 430

TimeStone = Timer()

If Spacekey() = 1

    Repeat
        if Timer() < TimeStone + 100
           DrawScreen()
           Sprite 1, StoneX#, StoneY, 15
           Dec StoneY, 20
           Dec StoneX#, 5.5
           TimeStone = Timer()
           sync 

rem First i tried without Sync, because in the MainLoop is already rem a Sync. But i could not see the Sprite until i placed a
rem Sync-Command in here

    Endif
    Until StoneY <= -30
    
ENDIF

Delete Bitmap 3
Delete Image 15
Endfunction

Thanks for help

Back to top

Profile PM

BillR

23

Years of Service

User Offline

Joined: 19th Mar 2003

Location: United States

Posted: 22nd Nov 2010 18:20 Edited at: 22nd Nov 2010 18:21

Link

A few suggestions...

Your ThrowStone function should not load and delete the stone.png bitmap and image every time you call the function, this is making your sprite flash. Load the graphics only ONCE at the beginning of your program

I like to keep ALL of my keyboard inputs during a game in one area, not in several different functions

use only one sync, at the bottom of the main loop. If you couldn't see the sprite with only your main loop sync, then there are logic problems in your code that need to be fixed, more example code would help

Back to top

Profile PM Email

DBProUser

15

Years of Service

User Offline

Joined: 28th Oct 2010

Location:

Posted: 22nd Nov 2010 18:47

Link

There are a Lot of Lines (ca. 1100) So it would be really tough to look through all the lines.

Here is my Main Loop, maybe it helps

+ Code Snippet

Do

   RandomNumber = 1
   ApePos = RND(430) + 50
   CLS bcolor
   DrawScreen()
   MoveHero()
   rem ThrowStone() <- i removed this in the MoveHero-Func.
   Jump=MoveApe(Jump)
   ThrowBanana()

   if Action = 1 then Herostep = 10

   if ScoreScale >= 300
      LevelCounter()
   EndIf

   If Inkey$() = "p" or Inkey$() = "P" and Pauseflag = 0
   Pauseflag = 1
   Pausefunc()
   Endif

   If Timer() >= Time+15000
       Time = 0
       Action = 0
       HeroStep = 4
   ENDIF

SYNC
Wait 100
LOOP

Now the Picture is Loading at the beginning of the Program like the other Pictures, but unfortunatly the result is still the same

+ Code Snippet

Function MoveHero()

If Leftkey() = 1 Then HeroX = HeroX - HeroStep
if HeroX < 10 Then HeroX = 10

If Rightkey() = 1 Then HeroX = HeroX + HeroStep
if HeroX > 600 Then HeroX = 600
Paste Image 11, HeroX, 430, 1

ThrowStone()

Endfunction

Function ThrowStone()

StoneX# = HeroX
StoneY = 430

TimeStone = Timer()

If Spacekey() = 1

    Repeat
        if Timer() < TimeStone + 100
           DrawScreen()
           Sprite 1, StoneX#, StoneY, 13
           Dec StoneY, 20
           Dec StoneX#, 5.5
           TimeStone = Timer()
           sync

    Endif
    Until StoneY <= -60

ENDIF


Endfunction

Back to top

Profile PM

BillR

23

Years of Service

User Offline

Joined: 19th Mar 2003

Location: United States

Posted: 22nd Nov 2010 19:12

Link

When you have an animated object in your game, you want a key press to set a variable such as throwflag=1, then in another function...
if throwflag=1 (then update animation, move object a little, etc)
when you are done with the animation, then reset throwflag=0.

What you don't want to do is wait in a function using repeat..until, while your animation finishes, pausing your entire game until it is done.

to review...
1)remove the repeat..until from your throwstone function
2)spacekey will set a flag variable like throwflag=1
3)Another function will update the animation if throwflag=1
4)if you want to have more than one stone, use arrays to keep track of all the objects you want animated on the screen, and update their position,etc. in the arrays, this works great.

Back to top

Profile PM Email

DBProUser

15

Years of Service

User Offline

Joined: 28th Oct 2010

Location:

Posted: 22nd Nov 2010 19:21 Edited at: 22nd Nov 2010 19:21

Link

Thanks a lot for your suggestions, i will try it out.

in the meantime i changed the Sprite to an Image. This works fine, without the flickering. But i dont want to use a Image, because Sprites are far more flexibel

+ Code Snippet

 Repeat
      if Timer() < TimeStone + 100
         CLS bcolor
         DrawScreen()
         Paste Image 13, StoneX#, StoneY, 1
         Dec StoneY, 20
         Dec StoneX#, 5.5
         TimeStone = Timer()
         sync

      Endif
    Until StoneY <= -60

this worked fine somehow

So back to the drawing-Board

Back to top

Profile PM

BillR

23

Years of Service

User Offline

Joined: 19th Mar 2003

Location: United States

Posted: 22nd Nov 2010 22:35 Edited at: 23rd Nov 2010 03:31

Link

Here is some code showing flags and arrays being used
to throw multiple rocks
Spacebar throws rock sprites

sync on
sync rate 60

global ThrowFlag=0
global RockTimer=0
global RockPtr=0

`stones(1)=active flag, 2=x, 3=y, 4=time
dim stones(100,5)

`make simple box texture
create bitmap 1,50,50
set current bitmap 1
box 0,0,20,20
Get image 1,0,0,20,20
delete bitmap 1
set current bitmap 0

`make sprites
for i=1 to 20
   sprite i,100,40*i,1
next i

do
   If Spacekey() = 1
      t=timer()               :`get time
      if t>RockTimer          :`can we throw another rock
         ThrowStone()         :`yep, throw rock
         RockTimer=t+100      :`timer until we can throw again
      endif
   endif
   AnimateStones()
   
   `debug code
   set cursor 0,0
   print "throwflag=";throwflag
   print "rockptr=";RockPtr
   
   sync
loop

Function ThrowStone()

`is a rock ready to throw, then load params for this stone into array
if ThrowFlag=0
   inc RockPtr,1
   if RockPtr>100 then RockPtr=1
   stones(RockPtr,1)=1                    :`active rock
   stones(RockPtr,2)=100                  :`x position
   Stones(RockPtr,3)=40*RockPtr           :`y position
   stones(RockPtr,4)=Timer()+5000         :`rocks will last for 5 seconds
   show sprite RockPtr
   ThrowFlag=1
Endif

Endfunction

Function AnimateStones()
t=timer()
if t>RockTimer then ThrowFlag=0  :`if it has been long anough, enable another rock can be thrown
for i=1 to 100
   if stones(i,1)>0              :`is rock active
      Sprite i, stones(i,2),stones(i,3),1
      inc stones(i,2),2
      if stones(i,4)<t           :`stone timer has run out
         stones(i,1)=0           :`rock is inactive now
         hide sprite i
      endif
   endif
next i
EndFunction

+ Code Snippet

sync on
sync rate 60

global ThrowFlag=0
global RockTimer=0
global RockPtr=0

`stones(1)=active flag, 2=x, 3=y, 4=time
dim stones(100,5)

`make simple box texture
create bitmap 1,50,50
set current bitmap 1
box 0,0,20,20
Get image 1,0,0,20,20
delete bitmap 1
set current bitmap 0

`make sprites
for i=1 to 20
   sprite i,100,40*i,1
next i


do
   If Spacekey() = 1
      t=timer()               :`get time
      if t>RockTimer          :`can we throw another rock
         ThrowStone()         :`yep, throw rock
         RockTimer=t+100      :`timer until we can throw again
      endif
   endif
   AnimateStones()
   
   `debug code
   set cursor 0,0
   print "throwflag=";throwflag
   print "rockptr=";RockPtr
   
   sync
loop


Function ThrowStone()

`is a rock ready to throw, then load params for this stone into array
if ThrowFlag=0
   inc RockPtr,1
   if RockPtr>100 then RockPtr=1
   stones(RockPtr,1)=1                    :`active rock
   stones(RockPtr,2)=100                  :`x position
   Stones(RockPtr,3)=40*RockPtr           :`y position
   stones(RockPtr,4)=Timer()+5000         :`rocks will last for 5 seconds
   show sprite RockPtr
   ThrowFlag=1
Endif

Endfunction


Function AnimateStones()
t=timer()
if t>RockTimer then ThrowFlag=0  :`if it has been long anough, enable another rock can be thrown
for i=1 to 100
   if stones(i,1)>0              :`is rock active
      Sprite i, stones(i,2),stones(i,3),1
      inc stones(i,2),2
      if stones(i,4)<t           :`stone timer has run out
         stones(i,1)=0           :`rock is inactive now
         hide sprite i
      endif
   endif
next i
EndFunction

Back to top

Profile PM Email

DBProUser

15

Years of Service

User Offline

Joined: 28th Oct 2010

Location:

Posted: 23rd Nov 2010 11:21 Edited at: 23rd Nov 2010 11:22

Link

Sorry for not answering earlier, but i think there is a little Time-Difference between the US and Germany (6 to 12 hours, it depends where)

Thank you for the Code-Example and for your help yesterday. I will try it out later, when i am at Home. Till then.

Back to top

Profile PM

Indicium

18

Years of Service

User Offline

Joined: 26th May 2008

Location:

Posted: 24th Nov 2010 21:42

Link

If there is a CLS command in your main game loop, remove it when using sprites.

Back to top

Profile PM

Hawkblood

16

Years of Service

User Offline

Joined: 5th Dec 2009

Location:

Posted: 30th Nov 2010 13:35

Link

I didn't see a "sync on" command. Without that, you will get a flicker with sprites.

The fastest code is the code never written.

Back to top

Profile PM Email Website

Sorry your browser is not supported!

DarkBASIC Professional Discussion / Flickering Screen after integrating Sprites