Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Simple Chipmunk Physics

  1. #1

    Simple Chipmunk Physics

    Hi,

    I feel a bit stupid, but is there anyone who could explain me how to implement the chipmunk physics in a Pascal program? I know there is cpInit etc. But let's assume I just want to have a ball which "bounces" and it is drawn with a simple circle function. Could anyone post some (pseudo)code which explains when I have to do the drawing? And how to "init" the physics system?
    Best regards,
    Cybermonkey

    Pulsar2D framework:
    http://pulsar2d.org

  2. #2
    Hmmm, demo11 from ZenGL maybe can help you with initialization of Chipmunk, and drawing... anyway it will be easy to translate into other engine/API As soon as I resolve a problem with translated Chipmunk demos into Pascal for Linux(using pure OpenGL and glut), I will add them to my Chipmunk Pascal binding - chipmunk-pascal.

  3. #3
    Okay, I guess I can initialize chipmunk, but again... In demo11 the drawing is done by
    Code:
      cpDrawSpace( space, TRUE );
    which means I have to "break down" the source of ZenGL. What if I would add a "ball" with your procedure
    Code:
    procedure cpAddBall( x, y, r, mass, e, u : cpFloat );
    how do I know where to draw the circle when physics were calculated. Assuming my procedure looks like
    Code:
    circle (x,y,radius)
    and my engine is purely procedural driven which means I have to establish a game loop like
    Code:
    repeat
      key=getkey();
      //do all the stuff
    until key=27;
    How can I get the x and y value of my ball?
    Best regards,
    Cybermonkey

    Pulsar2D framework:
    http://pulsar2d.org

  4. #4
    Ok, since no one can answer me, I'll post here an example from Freebasic
    Code:
     ''
     ''  My first chipmunk simulation
     ''
     #include "chipmunk/chipmunk.bi"
     #inclib "chipmunk"
     
    const as cpFloat mass = 5.0, radius = 10 ' Mass and radius values for our circle - you can play around with these
     const as cpFloat dt = 60.0 / 1.0 ' The delta time for physics calculations
     
    dim shared space as cpSpace ptr ' The space where the simulation takes place
     
    screenres 800, 600, 16 ' Setup the screen
     
    cpInitChipmunk() ' Initialize chipmunk
     
    space = cpSpaceNew() ' Create a new space
     space->iterations = 10 ' 10 Iterations per step
     space->gravity = cpv(0, 50) ' Gravity x = 0, y = 50 
     
    dim shared circleBody as cpBody ptr ' Circle body
     dim shared circleShape as cpShape ptr ' Circle shape
     
    ' Create a new circle body
     circleBody = cpBodyNew( mass, cpMomentForCircle( mass, 0.0, radius, cpvzero ) )
     circleBody->p = cpv( 400, 0 ) ' set the circle at the top-middle of the screen
     cpSpaceAddBody( space, circleBody ) ' add the body to the simulation
     
    ' Crate a new circle shape
     circleShape = cpCircleShapeNew( circleBody, radius, cpvzero )
     cpSpaceAddShape( space, circleShape ) ' add the shape to the simulation
     
    do
       screenlock()
         cls
         locate 1, 1: print "The ball should fall down into a bottomless pit"
     
        circle( circleBody->p.x, circleBody->p.y ), radius, rgb( 255, 0, 0 )
       screenunlock()
     
      ' Advance the simulation
       cpSpaceStep( space, dt )
     
      sleep 1, 1
     loop until multikey(&H01) ' Loop until Escape is pressed
     
    ' Cleans up everything associated with this space
     cpSpaceFreeChildren( space )
     cpSpaceFree( space )
     
    end 0
    So I will try to port this to FreePascal. (Of course there's still a timer missing but one step after the other ...)
    Best regards,
    Cybermonkey

    Pulsar2D framework:
    http://pulsar2d.org

  5. #5
    and my engine is purely procedural driven which means I have to establish a game loop like
    ZenGL is also fully procedural.

    How can I get the x and y value of my ball?
    Is it so hard to open zglChipmunk.pas and look to cpDrawSpace(and cpDrawShape), which is used in Draw function of demo11?

    // sorry for late answer...

  6. #6
    Quote Originally Posted by Andru View Post
    Hmmm, demo11 from ZenGL maybe can help you with initialization of Chipmunk, and drawing... anyway it will be easy to translate into other engine/API As soon as I resolve a problem with translated Chipmunk demos into Pascal for Linux(using pure OpenGL and glut), I will add them to my Chipmunk Pascal binding - chipmunk-pascal.
    A bit incomplete though, with libraries for Windows and Linux but not Mac. Also, a simple demo would be helpful.

    (And I am saying that just because FPC interfaces to Chipmunk Physics sounds really, really useful so I really want to try it!)
    Last edited by Ingemar; 30-07-2011 at 01:13 PM.

  7. #7
    A bit incomplete though, with libraries for Windows and Linux but not Mac. Also, a simple demo would be helpful.
    Mmm? And what is libchipmunk.5.3.2.dylib in bin directory do you think? This library, and simple demo, you can find with ZenGL(demo11). Unfortunately I have no time to finish that chipmunk demos, about which I said before.

  8. #8
    Maybe so but I was referring to what I found at the chipmunk-pascal link.

  9. #9
    Maybe so but I was referring to what I found at the chipmunk-pascal link.
    In chipmunk-pascal svn you can find libchipmunk.dylib too.

  10. #10
    Two days ago I took another look at the Chipmunk physics. Well, I made some progress, as you can see here (using my SDL based egslengine):



    However, I have a problem on Windows 32bit with the static linking (FPC 2.6.0) using the latest headers by Andru. Issue is
    Code:
    Target OS: Win32 for i386
    Compiling physictest.pas
    Linking physictest.exe
    physictest.pas(124,1) Error: Undefined symbol: _cpInitChipmunk
    physictest.pas(124,1) Error: Undefined symbol: _cpMomentForCircle
    physictest.pas(124,1) Fatal: There were 2 errors compiling module, stopping
    Fatal: Compilation aborted
    Any idea?
    Best regards,
    Cybermonkey

    Pulsar2D framework:
    http://pulsar2d.org

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comodo SSL