## Bouncing Balls with Soundcolors

Notes and Credits

Bouncing Balls with Soundcolors
is a much enlarged version of: http://scratch.mit.edu/projects/Canthiar/7369
by Canthiar

You now have colors an sounds and many parameters to play with:

Up / Down = -/+ Gravity
Left / Right = -/+ Emitter Speed
B / A = -/+ more Balls
1 = switch Edges
2 = switch Turn Effect
3 = switch Random
4 = switch Drawing
5 = switch Sound
Space = start Balls again

DragDrop Collision Objects
DragDrop Balls
DragDrop Emitter
Turn Emitter by pulling it's tip

H = Help (english)
G = Help (german)

Chantiers original description:
You can move the object emitter around with the mouse and change the direction by clicking on the pointed end.

This is what I consider a production version since I've inlined a few things. I have a more academic version that is a little easier to read. The whole thing is also dumbed down a little to make the math a little easier.

How it works:

When a ball encounters a collision object it uses the [ point towards[ Collision ] ] command block and then uses sin and cos to calculate a colliion normal. That normal is used to calculate a resulting velocity perpendicular to the surface and velocity tangent to the surface. Friction and restitution are applied to make the ball bounce.

Shared: 31 May 2007 Modified: 31 May 2007

More projects by MartinWollenweber