iPhone: Problem collision using accelerometer and chipmunk

Hi everybody !

I am facing a problem using chipmunk and iPhone accelerometer. Indeed, I defined a ball shape and body :

ballBody = cpBodyNew(100.0, INFINITY);
ballBody->p = cpv(160, 240);
cpSpaceAddBody(space, ballBody);    
cpShape *ballShape = cpCircleShapeNew(ballBody, 20.0, cpvzero);
ballShape->e = 0.5;
ballShape->u = 0.8; 
ballShape->collision_type = 1;

I want my ball to be able to move all around the iPhone screen and not more. For this, I defined walls all around the screen (apart from the top of the screen) :

cpBody *floorBody = cpBodyNew(INFINITY, INFINITY);
cpBody *wallBodyR = cpBodyNew(INFINITY, INFINITY);
cpBody *wallBodyL = cpBodyNew(INFINITY, INFINITY);

floorBody->p = cpv(160, 0);
wallBodyR->p = cpv(320, 240);
wallBodyL->p = cpv(0, 240);


cpShape *floorShape = cpSegmentShapeNew(floorBody, cpv(-160.0, 0.0), cpv(320.0, 0.0), 0);
cpShape *wallShapeR = cpSegmentShapeNew(wallBodyR, cpv(0.0, -240.0), cpv(0.0, 240.0), 0);
cpShape *wallShapeL = cpSegmentShapeNew(wallBodyL, cpv(0.0, -240.0), cpv(0.0, 240.0), 0);

floorShape->e = 0.5; floorShape->u = 0.1; floorShape->collision_type = 0;
wallShapeR->e = 0.5; wallShapeR->u = 0.1; wallShapeR->collision_type = 0;
wallShapeL->e = 0.5; wallShapeL->u = 0.1; wallShapeL->collision_type = 0;

cpSpaceAddStaticShape(space, floorShape);
cpSpaceAddStaticShape(space, wallShapeR);
cpSpaceAddStaticShape(space, wallShapeL);

I use those methods to make my ball move :

     - (void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration{
        accellX = acceleration.x * 10;
        accellY = acceleration.y * 10;
}

        -(void) step: (ccTime) dt{
        cpSpaceStep(space, dt);

        float newX = ballBody->p.x + accellX;
        float newY = ballBody->p.y + accellY;

        // move the sprite body to the new x position
        ballBody->p = cpv(newX, newY);

        // call our function for each shape
        cpSpaceHashEach(space->activeShapes, &updateShape, nil);
    }

void updateShape(void *ptr, void* unused)
{
    cpShape *shape = (cpShape *)ptr; // the shape
    CCSprite *sprite = shape->data; // the sprite

    // set the sprite position to the shapes body position
    [sprite setPosition: shape->body->p];
}

My problem is that my ball go through the walls when moving with the accelerometer. It clearly slow down when hurting a wall but it doesn't stop. If I give my space a gravity, the ball correctly stop and bounce when it hurts the floor (bottom wall), but don't when it hurts the left or right wall.

Any suggestions ?

PS: forgive my english, it's not my mother tongue.

ansaurus

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iPhone: Problem collision using accelerometer and chipmunk

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