bullet3/Demos/BasicDemo/BasicDemoPhysicsSetup.cpp

#include "BasicDemoPhysicsSetup.h"
#include "btBulletDynamicsCommon.h"
#define ARRAY_SIZE_Y 5
#define ARRAY_SIZE_X 5
#define ARRAY_SIZE_Z 5

void BasicDemoPhysicsSetup::initPhysics()
{
		///collision configuration contains default setup for memory, collision setup
	m_collisionConfiguration = new btDefaultCollisionConfiguration();
	//m_collisionConfiguration->setConvexConvexMultipointIterations();

	///use the default collision dispatcher. For parallel processing you can use a diffent dispatcher (see Extras/BulletMultiThreaded)
	m_dispatcher = new	btCollisionDispatcher(m_collisionConfiguration);

	m_broadphase = new btDbvtBroadphase();

	///the default constraint solver. For parallel processing you can use a different solver (see Extras/BulletMultiThreaded)
	btSequentialImpulseConstraintSolver* sol = new btSequentialImpulseConstraintSolver;
	m_solver = sol;

	m_dynamicsWorld = new btDiscreteDynamicsWorld(m_dispatcher,m_broadphase,m_solver,m_collisionConfiguration);
	
	
	m_dynamicsWorld->setGravity(btVector3(0,-10,0));

	///create a few basic rigid bodies
	btBoxShape* groundShape = createBoxShape(btVector3(btScalar(50.),btScalar(50.),btScalar(50.)));
	//groundShape->initializePolyhedralFeatures();
//	btCollisionShape* groundShape = new btStaticPlaneShape(btVector3(0,1,0),50);
	
	m_collisionShapes.push_back(groundShape);

	btTransform groundTransform;
	groundTransform.setIdentity();
	groundTransform.setOrigin(btVector3(0,-50,0));

	{
		btScalar mass(0.);
		createRigidBody(mass,groundTransform,groundShape);
	}


	{
		//create a few dynamic rigidbodies
		// Re-using the same collision is better for memory usage and performance

		btBoxShape* colShape = createBoxShape(btVector3(1,1,1));
		//btCollisionShape* colShape = new btSphereShape(btScalar(1.));
		m_collisionShapes.push_back(colShape);

		/// Create Dynamic Objects
		btTransform startTransform;
		startTransform.setIdentity();

		btScalar	mass(1.f);

		//rigidbody is dynamic if and only if mass is non zero, otherwise static
		bool isDynamic = (mass != 0.f);

		btVector3 localInertia(0,0,0);
		if (isDynamic)
			colShape->calculateLocalInertia(mass,localInertia);


		for (int k=0;k<ARRAY_SIZE_Y;k++)
		{
			for (int i=0;i<ARRAY_SIZE_X;i++)
			{
				for(int j = 0;j<ARRAY_SIZE_Z;j++)
				{
					startTransform.setOrigin(btVector3(
										btScalar(2.0*i),
										btScalar(20+2.0*k),
										btScalar(2.0*j)));

			
					createRigidBody(mass,startTransform,colShape);
				}
			}
		}
	}


}



void BasicDemoPhysicsSetup::stepSimulation(float deltaTime)
{
	m_dynamicsWorld->stepSimulation(deltaTime);
}

btBoxShape* BasicDemoPhysicsSetup::createBoxShape(const btVector3& halfExtents)
{
	btBoxShape* box = new btBoxShape(halfExtents);
	return box;
}

btRigidBody*	BasicDemoPhysicsSetup::createRigidBody(float mass, const btTransform& startTransform,btCollisionShape* shape)
{
	btAssert((!shape || shape->getShapeType() != INVALID_SHAPE_PROXYTYPE));

	//rigidbody is dynamic if and only if mass is non zero, otherwise static
	bool isDynamic = (mass != 0.f);

	btVector3 localInertia(0,0,0);
	if (isDynamic)
		shape->calculateLocalInertia(mass,localInertia);

	//using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects

#define USE_MOTIONSTATE 1
#ifdef USE_MOTIONSTATE
	btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform);

	btRigidBody::btRigidBodyConstructionInfo cInfo(mass,myMotionState,shape,localInertia);

	btRigidBody* body = new btRigidBody(cInfo);
	//body->setContactProcessingThreshold(m_defaultContactProcessingThreshold);

#else
	btRigidBody* body = new btRigidBody(mass,0,shape,localInertia);
	body->setWorldTransform(startTransform);
#endif//
	
	body->setUserIndex(-1);
	m_dynamicsWorld->addRigidBody(body);
	return body;
}


void BasicDemoPhysicsSetup::exitPhysics()
{
	//cleanup in the reverse order of creation/initialization
	
	//remove the rigidbodies from the dynamics world and delete them
	int i;
	for (i=m_dynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--)
	{
		btCollisionObject* obj = m_dynamicsWorld->getCollisionObjectArray()[i];
		btRigidBody* body = btRigidBody::upcast(obj);
		if (body && body->getMotionState())
		{
			delete body->getMotionState();
		}
		m_dynamicsWorld->removeCollisionObject( obj );
		delete obj;
	}

	//delete collision shapes
	for (int j=0;j<m_collisionShapes.size();j++)
	{
		btCollisionShape* shape = m_collisionShapes[j];
		delete shape;
	}
	m_collisionShapes.clear();

	delete m_dynamicsWorld;
	
	delete m_solver;
	
	delete m_broadphase;
	
	delete m_dispatcher;

	delete m_collisionConfiguration;

}