Optimal Collision Detection « cocos2d for iPhone

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Optimal Collision Detection

(6 posts) (5 voices)

Started 10 months ago by Dynex
Latest reply from Dynex

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Dynex
Member

Hey guys, I need some more advice.

My game is going to consist of many sprites (in the higher levels). These sprites include many different targets and many projectiles.

Would the best method of collision detection be to use CGRectIntersectsRect? Or should I dive into Box2d?
I have CGRectIntersectsRect working right now for regular non-animated sprites, but I'm having trouble with animated ones (which they all will be in the end)

Have any of you had to deal with collision detection with many sprites (30-40)?

Posted 10 months ago #
Birkemose
Moderator

With 30-40 sprites, you should definitely look into a physics engine.
Search for ccbox2d or objective chipmunk.

Posted 10 months ago #
Gray Olson
Member

Both physics engines above would be good choices for that number. Current ly I'm tracking 100-150 sprites at 30.0 fps, all moving, solid using ccbox2d

Posted 10 months ago #
ehoffman
Member

It depends mainly on the type of your sprites. If you have simple primitives (rect/quad, circle) you can do without a physics engine. For rects/quads use CGRectIntersectsRect. For two circles, they collide if the distance between both center points is less than the sum of both radiuses.

Depends on your game how accurate this needs to be.

If you have a lot of irregular sprites use a method like this: http://www.cocos2d-iphone.org/forum/topic/15539

But if you not only want collision detection, but also real movement of your objects you should use a physics engine: Chipmunk (Objective Chipmunk) or Box2d (ccbox2d). There you get the collision detection "for free", quasi as a side effect. ;) -> for more complex polygons, too.

Posted 10 months ago #
Aorata
Member

Use Box2d collision detection, it just works better, its more efficient...

Here is a tutorial on how to use them
http://www.raywenderlich.com/606/how-to-use-box2d-for-just-collision-detection-with-cocos2d-iphone