Super Balls

This movie demonstrates basic collision detection and bouncing. You may grab the balls with your mouse and throw them around.

Each superball is a movie clip which keeps track of its own velocity in the variables vx and vy. vx and vy are added to _x and _y, respectively, to move the balls around the Stage.

vy is affected by gravity, which causes the balls to drop towards the floor. And both vx and vy are affected by air resistance, which causes the balls to slow down over time.

Whenever the balls collide with a floor, ceiling or wall, their velocity in either the x or y direction is reversed, and they also lose some speed due to the collision.

When two balls collide with each other, they trade energy (the slow ball goes fast and the fast ball goes slow). They travel in the opposite direction of the collision, and also some energy is lost, due to the collision.