Help getting started with bullet in my application

[Warpedstone]

Hello everyone,

I have successfully installed bullet and compiled the helloworld example. Now what? How do I interface bullet with another 3D world? There doesn't seem to be any examples of anyone doing this. How do I get bullet to respond to the 3D world I have and move the objects in it.

Thanks for any help,
Warped

[winspear]

Create the graphics and the physics objects separately. Then while drawing the graphics objects, just get the motion state transform from physics and push it in to the graphics object. Thats it

For example: This is to create a simple cube of side 1.0

Physics object creation:

Code: Select all

btRigidBody* addPhysicsBox( btVector3 &boxHalfExtends, btVector3 &position, btVector3 &inertia, btScalar mass, btScalar restitution, bool collision ){
	btTransform trans;
	trans.setIdentity();
	trans.setOrigin( position );
	
	btCollisionShape *geom = new btBoxShape ( boxHalfExtends );
	geom->calculateLocalInertia( mass, inertia );

	btDefaultMotionState* motionstate = new btDefaultMotionState( trans );
	btRigidBody* body = new btRigidBody( mass, motionstate, geom, inertia );

	m_world->addRigidBody( body );
	
	if( collision )
		m_collisionShapes.push_back(geom);

	return body;
}

btRigidBody* boxActor;

boxActor = addPhysicsBox(btVector3(0.5,0.5,0.5),btVector3(0.0,5.0,0.0),
			btVector3(0.0,0.0,0.0),1.0,0.2,true);

Graphics object display:

Code: Select all

void renderCube(float m_Side, btTransform &boxTransform)
{
	GLfloat tempForm[16];
	boxTransform.getOpenGLMatrix(tempForm);

	glPushMatrix();

	glMultMatrixf(tempForm);

        glutSolidCube(m_Side);

	glPopMatrix();
}

renderCube(1.0, boxActor->getWorldTransform());

To get Motion state transform:

Code: Select all

void getBulletTransform(btRigidBody* rigidBody) 
{
	btMotionState* shapeMotionTransform;
	shapeMotionTransform = rigidBody->getMotionState();
	float openGLTransform[16];
	btTransform worldTransform;
	shapeMotionTransform->getWorldTransform(worldTransform);
	worldTransform.getOpenGLMatrix(openGLTransform);

     //Return the motion state opengl transform however you want

}

[Warpedstone]

Thanks winspear! I should be able to figure it out from here. If I run into anymore problems I will let you know. I can't believe there wasn't already several posts asking how to get started.

Anyway, thanks again,
Warped