Answer by FlySwat for Ball to Ball Collision - Detection and Handling

You have two easy ways to do this. Jay has covered the accurate way of checking from the center of the ball.

The easier way is to use a rectangle bounding box, set the size of your box to be 80% the size of the ball, and you'll simulate collision pretty well.

Add a method to your ball class:

public Rectangle getBoundingRect(){   int ballHeight = (int)Ball.Height * 0.80f;   int ballWidth = (int)Ball.Width * 0.80f;   int x = Ball.X - ballWidth / 2;   int y = Ball.Y - ballHeight / 2;   return new Rectangle(x,y,ballHeight,ballWidth);}

Then, in your loop:

// Checks every ball against every other ball. // For best results, split it into quadrants like Ryan suggested. // I didn't do that for simplicity here.for (int i = 0; i < balls.count; i++){    Rectangle r1 = balls[i].getBoundingRect();    for (int k = 0; k < balls.count; k++)    {        if (balls[i] != balls[k])        {            Rectangle r2 = balls[k].getBoundingRect();            if (r1.Intersects(r2))            {                 // balls[i] collided with balls[k]            }        }    }}