How to determine the collision of a circle with a rectangle? [duplicate]

Answer 1

I have no idea if Cocos provides a function to do this, but the math is really quite simple.

You take the two center points of the circles, and get the distance between them using your standard distance formula. float distance = sqrt(pow((x2-x1), 2) + pow((y2-y1), 2) and check if that is less than the sum of the radius of the two circles you're checking.

BOOL checkCircleCollision(CGPoint center1, float radius1, CGPoint center2, float radius2)
{
    float distance = sqrt(pow((center2.x-center1.x), 2) + pow((center2.y-center1.y), 2);
    return distance < (radius1 + radius2);
}

BOOL optimized_CheckCircleCollision(CGPoint center1, float radius1, CGPoint center2, float radius2)
{
    float a = center2.x - center1.x;
    float b = center2.y - center1.y;
    float c = radius1 + radius2;
    float distanceSqrd = (a * a) + (b * b);
    return distanceSqrd < (c * c);
}