Rectangle and Circle collision detection

Question

I am trying to do collision detection between a rectangle and a circle. I came up with this method:

-(BOOL) isCollidingRect:(CCSprite *) spriteOne WithSphere:(CCSprite *) spriteTwo {
    float diff = ccpDistance(spriteOne.position, spriteTwo.position);
    float obj1Radii = [spriteOne boundingBox].size.width/2;
    float obj2Radii = [spriteTwo boundingBox].size.width/2;
    if (diff < obj1Radii + obj2Radii) {
        return YES;
    } else {
        return NO;
    }
}

and this is how I check it:

if ([self isCollidingRect:player WithSphere:blocker] == true) {
   [self playerdeathstart];
}

This seems to work properly on the side of the rectangle but it doesn't above or below it. On the top and bottom, the collision occurs too early.

Is there a way I can get this collision to detected properly? Thank you for your help.

Answer 1

You can use CGRectIntersectsRect to achieve this.

-(BOOL) isCollidingRect:(CCSprite *) spriteOne WithSphere:(CCSprite *) spriteTwo {
    return CGRectIntersectsRect([spriteOne boundingBox],[spriteTwo boundingBox]);
}

It is not pixel perfect but as i understand that is not necessary in this case.