Problem with my first project. - GameCreators Forum

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akeith83

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Joined: 3rd May 2011

Location: Ohio, USA

Posted: 4th May 2011 07:19

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I'm going through the book "DarkBASIC Pro Game Programming, 2nd Ed. and I'm having a problem with my first project. Its a basic pong type game but the ball only moves up and down, but not side to side. I doublechecked that I copied everything correctly. Could anyone take a look at my code and help me find what I did wrong?

rem Simple Pong game

rem make some variables
ballx as integer = 320
bally as integer = 240
speedx as integer = -2
speedy as integer = 1
px1 as integer = 600
py1 as integer = 240
px2 as integer = 20
py2 as integer = 240
score1 as integer = 0
score2 as integer = 0

rem slow down the game
sync on
sync rate 40

rem the game runs in a loop
do 
    cls
    
    rem check shift/ctrl keys to move the left paddle
    if shiftkey()
        dec py2, 2
        if py2 < 0 then py2 = 0
      endif
    if controlkey()
        inc py2, 2
        if py2 > 470 then py2 = 470
      endif
    
    rem check up/down keys to move the right paddle
    if upkey()
        dec py1, 2
        if py1 < 0 then py1 = 0
      endif
    if downkey()
        inc py1, 2
        if py1 > 470 then py1 = 470
      endif
      
      rem move the ball
      inc ballx, speedx
      inc bally, speedy
      
      rem bounce ball off top/bottom of the screen
      if bally < 0 or bally > 470 then speedy = speedy*-1
      
      rem see if left player missed the ball
      rem if so, player 2 scores, reset the ball
      if ballx < 0
        inc score2, 1
        ballx = 320
        bally = 240
        speedx = 2
        sleep 500
       endif
      
      rem see if right player missed the ball
      rem if so, player 1 scores, reset the ball
      if ballx > 630
        inc score1, 1
        ballx = 320
        bally = 240
        speedx = -2
        sleep 500
       endif
      
      rem draw the ball
      circle ballx, bally, 10
      
      rem draw the baddles
      box px1, py1, px1+16, py1+64
      box px2, py2, px2+16, py2+64
      
      rem let's see if the ball has hit the paddle
      if point(ballx+5,bally+5) > 0
        speedx = speedx*-1
       endif
       
      rem print the scores
      text 0,0, "Score" +str$(score1)
      text 550,0, "Score" +str$(score2)
      
      rem draw the screen
      sync
                
LOOP

+ Code Snippet

rem Simple Pong game

rem make some variables
ballx as integer = 320
bally as integer = 240
speedx as integer = -2
speedy as integer = 1
px1 as integer = 600
py1 as integer = 240
px2 as integer = 20
py2 as integer = 240
score1 as integer = 0
score2 as integer = 0

rem slow down the game
sync on
sync rate 40

rem the game runs in a loop
do 
    cls
    
    rem check shift/ctrl keys to move the left paddle
    if shiftkey()
        dec py2, 2
        if py2 < 0 then py2 = 0
      endif
    if controlkey()
        inc py2, 2
        if py2 > 470 then py2 = 470
      endif
    
    rem check up/down keys to move the right paddle
    if upkey()
        dec py1, 2
        if py1 < 0 then py1 = 0
      endif
    if downkey()
        inc py1, 2
        if py1 > 470 then py1 = 470
      endif
      
      rem move the ball
      inc ballx, speedx
      inc bally, speedy
      
      rem bounce ball off top/bottom of the screen
      if bally < 0 or bally > 470 then speedy = speedy*-1
      
      rem see if left player missed the ball
      rem if so, player 2 scores, reset the ball
      if ballx < 0
        inc score2, 1
        ballx = 320
        bally = 240
        speedx = 2
        sleep 500
       endif
      
      rem see if right player missed the ball
      rem if so, player 1 scores, reset the ball
      if ballx > 630
        inc score1, 1
        ballx = 320
        bally = 240
        speedx = -2
        sleep 500
       endif
      
      rem draw the ball
      circle ballx, bally, 10
      
      rem draw the baddles
      box px1, py1, px1+16, py1+64
      box px2, py2, px2+16, py2+64
      
      rem let's see if the ball has hit the paddle
      if point(ballx+5,bally+5) > 0
        speedx = speedx*-1
       endif
       
      rem print the scores
      text 0,0, "Score" +str$(score1)
      text 550,0, "Score" +str$(score2)
      
      rem draw the screen
      sync
                
LOOP

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Daniel wright 2311

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Posted: 4th May 2011 08:42 Edited at: 4th May 2011 08:47

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When you inc your positions you first need to declear them, you did not do this, but here is a real good example pong game already set up from me dong a search.You can learn just from looking at the code. Also you should do it with sprites so all you need to do is move the sprite and not incress any positions.just make a sprite out of the ball you drew like in this demo project.

Rem Project: Pong
Rem Created: 28/11/2002 20:07:19

Rem ***** Main Source File *****

rem draw bats and ball
box 0,0,10,30
get image 1,0,0,8,8 rem--he got image here to use the image he created from the box he made
get image 2,0,0,10,30

rem set sync rate
sync rate 60
sync on

rem initiate ball sprite
sprite 1,0,0,1 rem here he made a sprite out of the first get image he made from the box he created
rem set bats to default positions
bat1_y=220
bat2_y=220

rem player first to serve
serve=1
gosub serve

do

rem draw borders
   box 0,15,640,25
   box 0,470,640,480

rem display scores
   text 0,0,"Player score: "+str$(score1)
   text 200,0,"Cpu score: "+str$(score2)

rem player control
   if keystate(30)=1 then dec bat1_y,6
   if keystate(44)=1 then inc bat1_y,6
   if bat1_y<25 then bat1_y=25
   if bat1_y>440 then bat1_y=440

rem ai
   if sprite angle(1)<180 and sprite x(1)>100
      if sprite y(1)>bat2_y then inc bat2_Y,6
      if sprite y(1)<bat2_y then dec bat2_Y,6
      if bat2_y<25 then bat2_y=25
      if bat2_y>440 then bat2_y=440
   endif

rem here he is moving the said ball he created

rem move ball
   move sprite 1,7
   rem move bats
   sprite 2,10,bat1_y,2
   sprite 3,620,bat2_y,2

rem ball to bat deflection
   if sprite collision(1,2)=1 or sprite collision(1,3)=1
      ang=wrapvalue(sprite angle(1)+rnd(90)+90)
      rotate sprite 1,ang
   endif

rem ball to wall deflection
   if sprite y(1)>462
      ang=wrapvalue(180-sprite angle(1))
      rotate sprite 1,ang
   endif
   if sprite y(1)<25
      ang=wrapvalue(180-sprite angle(1))
      rotate sprite 1,ang
   endif

rem ball out detection
   if sprite x(1)>640
      serve=1
      gosub serve
      inc score1
   endif
   if sprite x(1)<0
      serve=2
      gosub serve
      inc score2
   endif

sync

loop

serve:
   if serve=1
      x=25
      ang=rnd(90)+45
   endif
   if serve=2
      x=615
      ang=rnd(90)+225
   endif
   y=rnd(380)+50
   sprite 1,x,y,1
   rotate sprite 1,ang
return

+ Code Snippet

Rem Project: Pong
Rem Created: 28/11/2002 20:07:19

Rem ***** Main Source File *****

rem draw bats and ball
box 0,0,10,30
get image 1,0,0,8,8 rem--he got image here to use the image he created from the box he made
get image 2,0,0,10,30

rem set sync rate
sync rate 60
sync on

rem initiate ball sprite
sprite 1,0,0,1 rem here he made a sprite out of the first get image he made from the box he created
rem set bats to default positions
bat1_y=220
bat2_y=220

rem player first to serve
serve=1
gosub serve

do

   rem draw borders
   box 0,15,640,25
   box 0,470,640,480

   rem display scores
   text 0,0,"Player score: "+str$(score1)
   text 200,0,"Cpu score: "+str$(score2)

   rem player control
   if keystate(30)=1 then dec bat1_y,6
   if keystate(44)=1 then inc bat1_y,6
   if bat1_y<25 then bat1_y=25
   if bat1_y>440 then bat1_y=440

   rem ai
   if sprite angle(1)<180 and sprite x(1)>100
      if sprite y(1)>bat2_y then inc bat2_Y,6
      if sprite y(1)<bat2_y then dec bat2_Y,6
      if bat2_y<25 then bat2_y=25
      if bat2_y>440 then bat2_y=440
   endif

rem here he is moving the said ball he created

   rem move ball
   move sprite 1,7
   rem move bats
   sprite 2,10,bat1_y,2
   sprite 3,620,bat2_y,2

   rem ball to bat deflection
   if sprite collision(1,2)=1 or sprite collision(1,3)=1
      ang=wrapvalue(sprite angle(1)+rnd(90)+90)
      rotate sprite 1,ang
   endif

   rem ball to wall deflection
   if sprite y(1)>462
      ang=wrapvalue(180-sprite angle(1))
      rotate sprite 1,ang
   endif
   if sprite y(1)<25
      ang=wrapvalue(180-sprite angle(1))
      rotate sprite 1,ang
   endif

   rem ball out detection
   if sprite x(1)>640
      serve=1
      gosub serve
      inc score1
   endif
   if sprite x(1)<0
      serve=2
      gosub serve
      inc score2
   endif

   sync

loop

serve:
   if serve=1
      x=25
      ang=rnd(90)+45
   endif
   if serve=2
      x=615
      ang=rnd(90)+225
   endif
   y=rnd(380)+50
   sprite 1,x,y,1
   rotate sprite 1,ang
return

my signature keeps being erased by a mod So this is my new signature.

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Jimmy

22

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Joined: 20th Aug 2003

Location: Back in the USA

Posted: 4th May 2011 11:00

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@akeith83: That's strange, the code works fine on my computer. Do you have the latest DBP upgrade (7.6 or 7.7 RC) installed?

May 10th / Geek Culture / Jerico2day-OBese87 / VOTE

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Hodgey

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Joined: 10th Oct 2009

Location: Australia

Posted: 4th May 2011 11:23 Edited at: 4th May 2011 11:24

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Quote: "That's strange, the code works fine on my computer. "

It works fine on mine as well but I do remember this problem when I was going through this book. What I think is happening is that since the ball is white and the point command checks for a pixel greater than black, it sees the ball's pixels as white and changes the xspeed. The easiest solution is as Jimmy suggest, upgrad to the latest version of dbpro found here.

Here is the code that I used to get around it back when I had this problem.

Rem Project: Dark Basic Pro Project
Rem Created: Wednesday, May 04, 2011

Rem ***** Main Source File *****
rem Simple Pong game

rem make some variables
ballx as integer = 320
bally as integer = 240
speedx as integer = -2
speedy as integer = 1
px1 as integer = 600
py1 as integer = 240
px2 as integer = 20
py2 as integer = 240
score1 as integer = 0
score2 as integer = 0

rem slow down the game
sync on
sync rate 40

rem the game runs in a loop
do 
    cls
    
    rem check shift/ctrl keys to move the left paddle
    if shiftkey()
        dec py2, 2
        if py2 < 0 then py2 = 0
      endif
    if controlkey()
        inc py2, 2
        if py2 > 470 then py2 = 470
      endif
    
    rem check up/down keys to move the right paddle
    if upkey()
        dec py1, 2
        if py1 < 0 then py1 = 0
      endif
    if downkey()
        inc py1, 2
        if py1 > 470 then py1 = 470
      endif
      
      rem move the ball
      inc ballx, speedx
      inc bally, speedy
      
      rem bounce ball off top/bottom of the screen
      if bally < 0 or bally > 470 then speedy = speedy*-1
      
      rem see if left player missed the ball
      rem if so, player 2 scores, reset the ball
      if ballx < 0
        inc score2, 1
        ballx = 320
        bally = 240
        speedx = 2
        sleep 500
       endif
      
      rem see if right player missed the ball
      rem if so, player 1 scores, reset the ball
      if ballx > 630
        inc score1, 1
        ballx = 320
        bally = 240
        speedx = -2
        sleep 500
       endif
      
      rem draw the ball
      ink rgb(255, 0, 0)// change color of ball to red (no green in the ball)
      circle ballx, bally, 10
      ink rgb(255, 255,255) // change color of paddles to white
      
      rem draw the baddles
      box px1, py1, px1+16, py1+64
      box px2, py2, px2+16, py2+64
      
      rem let's see if the ball has hit the paddle
      if rgbg(point(ballx+5,bally+5)) > 0 // check that amount of green in the paddles > 0
        speedx = speedx*-1
       endif
       
      rem print the scores
      text 0,0, "Score" +str$(score1)
      text 550,0, "Score" +str$(score2)
      
      rem draw the screen
      sync
                
LOOP

+ Code Snippet

Rem Project: Dark Basic Pro Project
Rem Created: Wednesday, May 04, 2011

Rem ***** Main Source File *****
rem Simple Pong game

rem make some variables
ballx as integer = 320
bally as integer = 240
speedx as integer = -2
speedy as integer = 1
px1 as integer = 600
py1 as integer = 240
px2 as integer = 20
py2 as integer = 240
score1 as integer = 0
score2 as integer = 0

rem slow down the game
sync on
sync rate 40

rem the game runs in a loop
do 
    cls
    
    rem check shift/ctrl keys to move the left paddle
    if shiftkey()
        dec py2, 2
        if py2 < 0 then py2 = 0
      endif
    if controlkey()
        inc py2, 2
        if py2 > 470 then py2 = 470
      endif
    
    rem check up/down keys to move the right paddle
    if upkey()
        dec py1, 2
        if py1 < 0 then py1 = 0
      endif
    if downkey()
        inc py1, 2
        if py1 > 470 then py1 = 470
      endif
      
      rem move the ball
      inc ballx, speedx
      inc bally, speedy
      
      rem bounce ball off top/bottom of the screen
      if bally < 0 or bally > 470 then speedy = speedy*-1
      
      rem see if left player missed the ball
      rem if so, player 2 scores, reset the ball
      if ballx < 0
        inc score2, 1
        ballx = 320
        bally = 240
        speedx = 2
        sleep 500
       endif
      
      rem see if right player missed the ball
      rem if so, player 1 scores, reset the ball
      if ballx > 630
        inc score1, 1
        ballx = 320
        bally = 240
        speedx = -2
        sleep 500
       endif
      
      rem draw the ball
      ink rgb(255, 0, 0)// change color of ball to red (no green in the ball)
      circle ballx, bally, 10
      ink rgb(255, 255,255) // change color of paddles to white
      
      rem draw the baddles
      box px1, py1, px1+16, py1+64
      box px2, py2, px2+16, py2+64
      
      rem let's see if the ball has hit the paddle
      if rgbg(point(ballx+5,bally+5)) > 0 // check that amount of green in the paddles > 0
        speedx = speedx*-1
       endif
       
      rem print the scores
      text 0,0, "Score" +str$(score1)
      text 550,0, "Score" +str$(score2)
      
      rem draw the screen
      sync
                
LOOP

A clever person solves a problem, a wise person avoids it - Albert Einstein

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akeith83

15

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Joined: 3rd May 2011

Location: Ohio, USA

Posted: 4th May 2011 23:10

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I do have the latest update. I've tried it in win7 and winxp and my code still does the same thing.

And thank you for the code Hodgey that one worked great for me. I just can't understand why my code working for you guys and not me.

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IanM

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Joined: 11th Sep 2002

Location: In my moon base

Posted: 5th May 2011 00:19

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It's due to a difference in video cards.

When the video mode is set to a non-alpha mode, some cards pass back a colour with an alpha value of 0 and some pass it back with an alpha value of 255 - that means that if your card does pass back an alpha value of 255, it is interpreted as a negative value, as the high-bit is set - if you know how binary 2's complement numbers are represented, you'll know how that works.

What Hodgey's fix does is to extract the green component from the colour and use that instead, so that the comparison no longer relies on the alpha value.

Get the latest Matrix1Utility plug-ins (20-APR-2011)

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akeith83

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Joined: 3rd May 2011

Location: Ohio, USA

Posted: 5th May 2011 01:46

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Thanks IanM. That makes it a little more clear for me. The card I'm using is the saphire radeon 5570 1gb ddr3.

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Hodgey

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Joined: 10th Oct 2009

Location: Australia

Posted: 5th May 2011 09:39

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@ akeith83: glad my code works for you

@ IanM: you know more about my fix than I do

. One of these days you are going to have to tell me your secret on how you know so much, is it because you have a moon base?

A clever person solves a problem, a wise person avoids it - Albert Einstein

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