Trouble with Chipmunk's collision handler and variables...

Johanovski · May 2010

Hi there!

I'm working in a Cocos2D + Chipmunk game, and I'm trying to put some sound. I want to play a collision sound in the postSolve function of the Chipmunk's collision handler. However from within the function I'm not able to access global class' variables (like the sound engine) because XCode says me that those vars are not declared in this scope... How can this be solved?

Here is the code:


static void postSolveCollision(cpArbiter *arb, cpSpace *space,void *ignore)
{
   if (cpArbiterIsFirstContact(arb)) {
      if (cpArbiterTotalImpulse(arb).x * cpArbiterTotalImpulse(arb).y != 0) {
                        // \"sound\" is a boolean property
         if (self.sound) {
            [sharedSoundManager playSoundWithKey:@\"cop\" gain:1.0f pitch:1.0f location:Vector2fZero shouldLoop:NO];
         }
      }
   }
}

Thanks in advance! :)

manicaesar · May 2010

It is not working because you are trying to access ObjectiveC object from pure C function!

One possible solution is to declare global static variable like this:

static YourClass *global = nil;

initialize it somewhere and then you can use it from within your C function.

Johanovski · May 2010

Hi there!

I've solved it by passing "self" as a (void*) parameter and then cast it inside the function as a pointer to my class!

Thanks! :)

manicaesar · May 2010

Johanovski;201870 said:
Hi there!

I've solved it by passing "self" as a (void*) parameter and then cast it inside the function as a pointer to my class!

Thanks! :)

And that's the second possible solution ;)

Best Regards

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Trouble with Chipmunk's collision handler and variables...

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