bullet3/Demos/CommonRigidBodySetup.h

#ifndef COMMON_RIGID_BODY_SETUP_H
#define COMMON_RIGID_BODY_SETUP_H

//todo: replace this 'btBulletDynamicsCommon.h' header with specific used header files
#include "btBulletDynamicsCommon.h"
#include "CommonPhysicsSetup.h"

struct CommonRigidBodySetup : public CommonPhysicsSetup
{
		//keep the collision shapes, for deletion/cleanup
	btAlignedObjectArray<btCollisionShape*>	m_collisionShapes;
	btBroadphaseInterface*	m_broadphase;
	btCollisionDispatcher*	m_dispatcher;
	btConstraintSolver*	m_solver;
	btDefaultCollisionConfiguration* m_collisionConfiguration;
	btDiscreteDynamicsWorld* m_dynamicsWorld;
	
	//data for picking objects
	class btRigidBody*	m_pickedBody;
	class btTypedConstraint* m_pickedConstraint;
	btVector3 m_oldPickingPos;
	btVector3 m_hitPos;
	btScalar m_oldPickingDist;
	
	CommonRigidBodySetup()
	:m_broadphase(0),
		m_dispatcher(0),
		m_solver(0),
		m_collisionConfiguration(0),
		m_dynamicsWorld(0),
		m_pickedBody(0),
		m_pickedConstraint(0)
	{
	}
	
	virtual void createEmptyDynamicsWorld()
	{
		///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));
	}
	
	
	virtual void stepSimulation(float deltaTime)
	{
		if (m_dynamicsWorld)
		{
			m_dynamicsWorld->stepSimulation(deltaTime);
		}
	}	


	virtual void exitPhysics()
	{
		removePickingConstraint();
		//cleanup in the reverse order of creation/initialization

		//remove the rigidbodies from the dynamics world and delete them
		int i;
		for (i = m_dynamicsWorld->getNumConstraints() - 1; i >= 0; i--)
		{
			m_dynamicsWorld->removeConstraint(m_dynamicsWorld->getConstraint(i));
		}
		if (m_dynamicsWorld)
		{

			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;
	}
		
	virtual void syncPhysicsToGraphics(GraphicsPhysicsBridge& gfxBridge)
	{
		if (m_dynamicsWorld)
		{
			gfxBridge.syncPhysicsToGraphics(m_dynamicsWorld);
		}
	}

	virtual bool pickBody(const btVector3& rayFromWorld, const btVector3& rayToWorld)
	{
		if (m_dynamicsWorld==0)
			return false;

		btCollisionWorld::ClosestRayResultCallback rayCallback(rayFromWorld, rayToWorld);

		m_dynamicsWorld->rayTest(rayFromWorld, rayToWorld, rayCallback);
		if (rayCallback.hasHit())
		{
	
			btVector3 pickPos = rayCallback.m_hitPointWorld;
			btRigidBody* body = (btRigidBody*)btRigidBody::upcast(rayCallback.m_collisionObject);
			if (body)
			{
				//other exclusions?
				if (!(body->isStaticObject() || body->isKinematicObject()))
				{
					m_pickedBody = body;
					m_pickedBody->setActivationState(DISABLE_DEACTIVATION);
					//printf("pickPos=%f,%f,%f\n",pickPos.getX(),pickPos.getY(),pickPos.getZ());
					btVector3 localPivot = body->getCenterOfMassTransform().inverse() * pickPos;
					btPoint2PointConstraint* p2p = new btPoint2PointConstraint(*body, localPivot);
					m_dynamicsWorld->addConstraint(p2p, true);
					m_pickedConstraint = p2p;
					btScalar mousePickClamping = 30.f;
					p2p->m_setting.m_impulseClamp = mousePickClamping;
					//very weak constraint for picking
					p2p->m_setting.m_tau = 0.001f;
				}
			}
	
	
			//					pickObject(pickPos, rayCallback.m_collisionObject);
			m_oldPickingPos = rayToWorld;
			m_hitPos = pickPos;
			m_oldPickingDist = (pickPos - rayFromWorld).length();
			//					printf("hit !\n");
			//add p2p
		}
		return false;
	}
	virtual bool movePickedBody(const btVector3& rayFromWorld, const btVector3& rayToWorld)
	{
		if (m_pickedBody  && m_pickedConstraint)
		{
			btPoint2PointConstraint* pickCon = static_cast<btPoint2PointConstraint*>(m_pickedConstraint);
			if (pickCon)
			{
				//keep it at the same picking distance
	
				btVector3 newPivotB;
	
				btVector3 dir = rayToWorld - rayFromWorld;
				dir.normalize();
				dir *= m_oldPickingDist;
	
				newPivotB = rayFromWorld + dir;
				pickCon->setPivotB(newPivotB);
				return true;
			}
		}
		return false;
	}
	virtual void removePickingConstraint()
	{
		if (m_pickedConstraint)
		{
			m_dynamicsWorld->removeConstraint(m_pickedConstraint);
			delete m_pickedConstraint;
			m_pickedConstraint = 0;
			m_pickedBody = 0;
		}
	}
	


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

	btRigidBody*	createRigidBody(float mass, const btTransform& startTransform, btCollisionShape* shape,  const btVector4& color = btVector4(1, 0, 0, 1))
	{
		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;
	}
};

#endif //COMMON_RIGID_BODY_SETUP_H