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Cocos2d Chipmunk gravity and collision detection

I have a simple animation in Cocos2d Chipmunk with the tasks:

  • One round shaped sprite situated in the center of the screen, rigid body type. Center of gravity needs to be located in center of this sprite.
  • From different sides of screen (spontaneously and beyond screen size) other rigid round sprites must fall into central sprite to fill visible screen space.
  • Sprites should not overlap one another.

So the questions are:

  1. How to reassign the vector of gravity to the center of the screen?
  2. How to implement collision detection between rigid body types in Cocos2d Chipmunk?

Thanks, colleagues!

Solution

    1. You can't set a center for the gravity. You can only set a direction (the same for all objects). It's possible to create an effect you describe, but you'll have to do the work yourself. In every frame you have to set a force or apply an impulse on every body in the direction of your gravity. And the "regular" chipmunk gravity should be (0, 0).

    2. See this tutorial about collision detection.