questions about 2D physics on network...

[sjinny]

i need a simple physics engine :
2D simulation
linear&angular velocity without linear&angular acceleration ( so no need for the mass and force of objects )
only need shape level collision detection, no need for triangle mesh collision detection
only need stop or slide after collision, no need for physical collision reaction

since i will use it on the sever while also on the client, the performance is very important because of the large quantity of dynamic objects

i wonder if i should write a special engine for this or just use bullet ?
will the additional features of bullet cause low performance ? or i should customize bullet ? how ?
if i use bullet, how many dynamic objects can be simulated on a common server ( physics simulation only ) ?

thanks~

[Erwin Coumans]

i need a simple physics engine :
2D simulation
linear&angular velocity without linear&angular acceleration ( so no need for the mass and force of objects )
only need shape level collision detection, no need for triangle mesh collision detection
only need stop or slide after collision, no need for physical collision reaction

since i will use it on the sever while also on the client, the performance is very important because of the large quantity of dynamic objects
i wonder if i should write a special engine for this or just use bullet ?

If you need 2D only, you might consider using Box2D instead, see http://box2d.org

will the additional features of bullet cause low performance ? or i should customize bullet ? how ?
if i use bullet, how many dynamic objects can be simulated on a common server ( physics simulation only ) ?

It all depends, but on a reasonable current machine, Bullet can simulate at least around 1000 dynamic moving (active) objects on a static environment (millions of triangles if you like). However, you would not benefit from the 3D capabilities of Bullet, so if you really need 2D, you better pick a 2D engine.

Hope this helps,
Erwin

[sjinny]

thanks Erwin ~
but i can't open the url ...
can you recommend any documents of building a 2D physics engine ? i'm afraid i'll have to make it myself finally...