cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   mrTortex
   Member

   Hello. I've asked this in the Chipmunk forum also, I'm getting desperate after days and days of failures. Anyway, I simply want to move a Chipmunk body by setting it's position to be the same as a sprite's position which sits within a parallax node. The first part of my code creates the shape and body and adds the sprite, then removes the body from the space. Credit goes to Mobilebros for this.

   ppShape = [smgr addRectAt:ccp(160, 100) mass:INFINITY width:92 height:12 rotation:0];
   	cpSpaceRemoveBody(smgr.space, ppShape->body);
   	ppSprite = [cpCCSprite spriteWithShape:ppShape file:@"level1Pad.png"];

   This second bit is supposed to move the body around, but what happens is the body (or shape) stays where I put it. I believe the shape will move if I move the body, bt that appears to not happen and I can't move the collision shape.

   ppShape->body->p = ccp(_level1S.position.y + 10, _level1S.position.x + 160);

   So, to recap, I simply want a body not effected by gravity, which I can move by setting it's position to the position of a moving sprite. The body must allow things to collide with it.

   Help!

   Thanks.

   Posted 1 year ago #
2. 

   mobilebros
   Moderator

   Ah! I see your issue. SpaceManager actually thinks you want a static shape/body because of the mass you're passing....... so it puts it in the static section of chipmunk, meaning chipmunk doesn't think it ever moves... crap! Couple of solutions here:

   Give a mass thats not quite INFINITY (should work)
   

   ppShape = [smgr addRectAt:ccp(160, 100) mass:(INFINITY-1) width:92 height:12 rotation:0];

   Or manually take the shape out of the static section and put it in the correct "active" section:
   

   cpSpaceRemoveStaticShape(smgr.space, ppShape);
   cpSpaceAddShape(smgr.space, ppShape);

   Nasty nasty issue and hard to find if you don't know whats going on under the SpaceManager hood. Let me know if it still is weird.

   Posted 1 year ago #
3. 

   mrTortex
   Member

   Sweet, I'll give that a try now. :) If this works I'll send a kiss - o - gram. ;)

   Posted 1 year ago #
4. 

   mrTortex
   Member

   Damn, top one doesn't work and second one gives me an unsolvable collision which crashes the game.

   Posted 1 year ago #
5. 

   mrTortex
   Member

   Ok, ignoring the fact that this is an interesting, albeit annoying bug to fix, I think I am over complicating things.

   So, running things through in my head I believe it's simpler to fix everything in place and move the layer's camera. That way the physics objects will be revealed as the camera falls downwards with my player. I guess that will happen. :-)

   So, I'll try that and be back here in 30 when it fails ;-)

   Thanks for the help.

   Posted 1 year ago #

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