Please help me with cpSpaceAddCollisionPairFunc

[mbue]

Hi all,

I try to use chipmunk collisions to tell me if a car collided with a powerup in my game.
Unfortunately I'm having problems with cpSpaceAddCollisionPairFunc right now.

My stripped down code looks like this:

Code: Select all

int Phys_CollectPowerup (cpShape *a, cpShape *b, cpContact *contacts, int numContacts, cpFloat normal_coef, void *data)
{
[...]
}

static void Phys_Init (void)
{
	cpInitChipmunk();
	e.physics = cpSpaceNew();
[...]
	cpSpaceAddCollisionPairFunc(e.physics, COLL_CAR, COLL_POWERUP, &Phys_CollectPowerup, NULL); //&some_value);
}

EDIT Full code here
COLL_CAR and COLL_POWERUP are 1 and 2 respectively.

They are set for cars and powerups like this

Code: Select all

shape->collision_type = COLL_CAR;
and
shape->collision_type = COLL_POWERUP;

before adding the shapes and bodies to the space.

My problem is that Phys_CollectPowerup is never called.
Any ideas what I could've missed?
Is the order of adding shapes/bodies and the collision pair function important?

Thanks in advance,
Martin

[supertommy]

I think the code you posted looks ok.

Do the cars and powerups collide if you remove the function?

If, for instance, the car and the powerups are on different layers or in the same group, the collision function won't be called (as far as I can remember.)

[mbue]

supertommy many thanks for the answer.
I did rule out all your suggestions and realized that I didn't draw the powerup at the correct place (i.e. body->p was not set correctly, but it was draw at the right place anyway)

Martin