# Physics engine for Billiard game [closed]

I need to write a simple 3D billiard game using OpenGL. Which physics engine is simple and best to use in this case? Or it's better to write physics by myself?

## closed as not constructive by Sean Middleditch, bummzack, Josh♦, Trevor Powell, MichaelHouse♦Apr 4 '13 at 22:22

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• Is there any reason why you can't use a 2d physics simulation? After all, the action of the game all takes place within 2 dimensions, unless you're hitting the ball too hard or too low. But other than that the balls generally collide at their middle with all other objects in the game. I don't see why you couldn't just use a 2d simulation. Going full 3d physics just to allow players to knock the ball off the table seems overkill. – user6484 Mar 24 '13 at 13:31

I've written a simple 2D billiard-like game using Box2D before.

As Digital Architect pointed out, unless the ball jumps from the table, 3D physics is overkill. And you can use 2D physics with 3D graphics.

If you decided to implement physics by yourself, this is what you'd have to do (which are already implemented in Box2D):

1. Circle-Circle collision detection (when balls collide)
2. Circle-Polygon collision detection (when balls collide with the edges, which are not rectangles)
3. Handling collision (so that balls that collide move accordingly, depending on the coefficient of restitution)
4. Damping
5. Applying forces (or at least set the velocity of a ball)
6. Sensors (for the holes)

Also, you'd have to make sure everything works properly (no obvious bugs, which can be a pretty hard problem unless you really know what you are doing) and efficiently.

• Thanks for your answer, using 2D engine was obvious solution. Hope this will work for me. – DarkSun Mar 24 '13 at 13:57