cocos2d for iPhone

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

1. 

   gravity
   Member

   Is there a way to update the cpShape. I want to simulate an explosion that pushes other shapes aside and the best idea I have for it is to just quickly enlarge the shape and then remove it.

   But how to do this?

   The shape is just a circle. So I've been experimenting with creating a new shape, and replacing the old one.

   > cpSpaceRemoveShape(space, ball.ballShape);
   > cpFloat r = .5 * ball.radius; //radius is a property in my ball class
   > cpShape *shapeOfBall = ball.ballShape;
   > shapeOfBall = cpCircleShapeNew(ball.ballBody, r, cpvzero);
   > cpSpaceAddShape(space, shapeOfBall);

   But this isn't working, and I'm wondering if there's a better way to do it with less cpSpaceAddShape calls.

   Posted 2 years ago #
2. 

   crmagicxxx
   Member

   You can also iterate through all of your sprites/bodies for which you want explosion to have effect, calculate their vector position from the center of explosion and apply Impulse to all of them with negative vector...

   Posted 2 years ago #
3. 

   gravity
   Member

   Thanks. I think I'm going to go that way to make a more organic appearance.

   Is there a way to query a sub-space for bodies? I see you can query a point, and a space entirely, but what about a space around the explosion?

   Or would I need to iterate through all of the bodies in my space entirely to pick out the ones in the explosion range?

   Posted 2 years ago #
4. 

   gravity
   Member

   For future reference, I just iterated over all objects- I anticipate < 100, and that's already kind of costly (since I'm doing a displacement calculation each time) but damn it runs smoothly.

   Posted 2 years ago #
5. 

   crmagicxxx
   Member

   So, you made it or still need an answer to that sub-space question? :)

   Posted 2 years ago #

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