How to put stepSimulation

[smallping]

Hello, everyone, I am new to Bullet, but now I want to integrate bullet into my OpenGL project.
I check the wiki and demos, and I can almost understand the physics and graphics.
My question is that, should I put stepSimulation into glutDisplayFunc to start the Phyiscs iteration, or put into glutIdleFunc to start the Physics iteration?
I find some examples, they put stepSimulation into the glutDisplayFunc, others they put into glutIdleFunc? They are the same? or different?
Also my graphic fresh rate is about 30Hz, and I want my physics rate is at 100Hz, so I just set this function like: stepSimulation(1/100,1,1/60)? ok?

Thanks

[Basroil]

Also my graphic fresh rate is about 30Hz, and I want my physics rate is at 100Hz, so I just set this function like: stepSimulation(1/100,1,1/60)? ok?

You don't want to do that

It should be stepSimulation(elapsedTime, 3,1/100), where elapsed time is the time between step calls, 3 is a number large enough so that graphics lag doesn't mess with simulation rate (but small enough that if the computer isn't fast enough to handle it the accuracy will be reduced rather than spiral into oblivion), and then internal simulation step size (your 100hz simulation rate).
http://bulletphysics.org/mediawiki-1.5. ... _the_World explains this quite well.

[smallping]

Dear Basroil, thanks for your information.
So I can just do like this

......
glutIdleFunc(main_idle);
......

void main_idle(void)
{
float dtime = g_time;
g_time = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
dtime = g_time - dtime;

if(g_btDynamicsWorld)
g_btDynamicsWorld->stepSimulation(dtime, 10, 0.01);

glutPostRedisplay();
}

Is that right? I try and it works

[Basroil]

Sounds about right, though there's a bullet timer built in that does the same thing too if you want more bullet in your program.