/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef RIGIDBODY_H
#define RIGIDBODY_H

#include "LinearMath/btAlignedObjectArray.h"
#include "LinearMath/btPoint3.h"
#include "LinearMath/btTransform.h"
#include "BulletCollision/BroadphaseCollision/btBroadphaseProxy.h"
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"

class btCollisionShape;
class btMotionState;
class btTypedConstraint;


extern btScalar gDeactivationTime;
extern bool gDisableDeactivation;


///btRigidBody is the main class for rigid body objects. It is derived from btCollisionObject, so it keeps a pointer to a btCollisionShape.
///It is recommended for performance and memory use to share btCollisionShape objects whenever possible.
///There are 3 types of rigid bodies: 
///- A) Dynamic rigid bodies, with positive mass. Motion is controlled by rigid body dynamics.
///- B) Fixed objects with zero mass. They are not moving (basically collision objects)
///- C) Kinematic objects, which are objects without mass, but the user can move them. There is on-way interaction, and Bullet calculates a velocity based on the timestep and previous and current world transform.
///Bullet automatically deactivates dynamic rigid bodies, when the velocity is below a threshold for a given time.
///Deactivated (sleeping) rigid bodies don't take any processing time, except a minor broadphase collision detection impact (to allow active objects to activate/wake up sleeping objects)
class btRigidBody  : public btCollisionObject
{

	btMatrix3x3	m_invInertiaTensorWorld;
	btVector3		m_linearVelocity;
	btVector3		m_angularVelocity;
	btScalar		m_inverseMass;
	btScalar		m_angularFactor;

	btVector3		m_gravity;	
	btVector3		m_invInertiaLocal;
	btVector3		m_totalForce;
	btVector3		m_totalTorque;
	
	btScalar		m_linearDamping;
	btScalar		m_angularDamping;

	bool			m_additionalDamping;
	btScalar		m_additionalDampingFactor;
	btScalar		m_additionalLinearDampingThresholdSqr;
	btScalar		m_additionalAngularDampingThresholdSqr;
	btScalar		m_additionalAngularDampingFactor;


	btScalar		m_linearSleepingThreshold;
	btScalar		m_angularSleepingThreshold;

	//m_optionalMotionState allows to automatic synchronize the world transform for active objects
	btMotionState*	m_optionalMotionState;

	//keep track of typed constraints referencing this rigid body
	btAlignedObjectArray<btTypedConstraint*> m_constraintRefs;

public:


	///btRigidBodyConstructionInfo provides information to create a rigid body. Setting mass to zero creates a fixed (non-dynamic) rigid body.
	///For dynamic objects, you can use the collision shape to approximate the local inertia tensor, otherwise use the zero vector (default argument)
	///You can use the motion state to synchronize the world transform between physics and graphics objects. 
	///And if the motion state is provided, the rigid body will initialize its initial world transform from the motion state,
	///m_startWorldTransform is only used when you don't provide a motion state.
	struct	btRigidBodyConstructionInfo
	{
		btScalar			m_mass;

		///When a motionState is provided, the rigid body will initialize its world transform from the motion state
		///In this case, m_startWorldTransform is ignored.
		btMotionState*		m_motionState;
		btTransform	m_startWorldTransform;

		btCollisionShape*	m_collisionShape;
		btVector3			m_localInertia;
		btScalar			m_linearDamping;
		btScalar			m_angularDamping;

		///best simulation results when friction is non-zero
		btScalar			m_friction;
		///best simulation results using zero restitution.
		btScalar			m_restitution;

		btScalar			m_linearSleepingThreshold;
		btScalar			m_angularSleepingThreshold;

		//Additional damping can help avoiding lowpass jitter motion, help stability for ragdolls etc.
		//Such damping is undesirable, so once the overall simulation quality of the rigid body dynamics system has improved, this should become obsolete
		bool				m_additionalDamping;
		btScalar			m_additionalDampingFactor;
		btScalar			m_additionalLinearDampingThresholdSqr;
		btScalar			m_additionalAngularDampingThresholdSqr;
		btScalar			m_additionalAngularDampingFactor;

		
		btRigidBodyConstructionInfo(	btScalar mass, btMotionState* motionState, btCollisionShape* collisionShape, const btVector3& localInertia=btVector3(0,0,0)):
		m_mass(mass),
			m_motionState(motionState),
			m_collisionShape(collisionShape),
			m_localInertia(localInertia),
			m_linearDamping(btScalar(0.)),
			m_angularDamping(btScalar(0.)),
			m_friction(btScalar(0.5)),
			m_restitution(btScalar(0.)),
			m_linearSleepingThreshold(btScalar(0.8)),
			m_angularSleepingThreshold(btScalar(1.f)),
			m_additionalDamping(false),
			m_additionalDampingFactor(btScalar(0.005)),
			m_additionalLinearDampingThresholdSqr(btScalar(0.01)),
			m_additionalAngularDampingThresholdSqr(btScalar(0.01)),
			m_additionalAngularDampingFactor(btScalar(0.01))
		{
			m_startWorldTransform.setIdentity();
		}
	};

	///btRigidBody constructor using construction info
	btRigidBody(	const btRigidBodyConstructionInfo& constructionInfo);

	///btRigidBody constructor for backwards compatibility. 
	///To specify friction (etc) during rigid body construction, please use the other constructor (using btRigidBodyConstructionInfo)
	btRigidBody(	btScalar mass, btMotionState* motionState, btCollisionShape* collisionShape, const btVector3& localInertia=btVector3(0,0,0));


	virtual ~btRigidBody()
        { 
                //No constraints should point to this rigidbody
		//Remove constraints from the dynamics world before you delete the related rigidbodies. 
                btAssert(m_constraintRefs.size()==0); 
        }

protected:

	///setupRigidBody is only used internally by the constructor
	void	setupRigidBody(const btRigidBodyConstructionInfo& constructionInfo);

public:

	void			proceedToTransform(const btTransform& newTrans); 
	
	///to keep collision detection and dynamics separate we don't store a rigidbody pointer
	///but a rigidbody is derived from btCollisionObject, so we can safely perform an upcast
	static const btRigidBody*	upcast(const btCollisionObject* colObj)
	{
		return (const btRigidBody*)colObj->getInternalOwner();
	}
	static btRigidBody*	upcast(btCollisionObject* colObj)
	{
		return (btRigidBody*)colObj->getInternalOwner();
	}
	
	/// continuous collision detection needs prediction
	void			predictIntegratedTransform(btScalar step, btTransform& predictedTransform) ;
	
	void			saveKinematicState(btScalar step);
	
	void			applyGravity();
	
	void			setGravity(const btVector3& acceleration);  

	const btVector3&	getGravity() const
	{
		return m_gravity;
	}

	void			setDamping(btScalar lin_damping, btScalar ang_damping);

	void			applyDamping(btScalar timeStep);

	SIMD_FORCE_INLINE const btCollisionShape*	getCollisionShape() const {
		return m_collisionShape;
	}

	SIMD_FORCE_INLINE btCollisionShape*	getCollisionShape() {
			return m_collisionShape;
	}
	
	void			setMassProps(btScalar mass, const btVector3& inertia);
	
	btScalar		getInvMass() const { return m_inverseMass; }
	const btMatrix3x3& getInvInertiaTensorWorld() const { 
		return m_invInertiaTensorWorld; 
	}
		
	void			integrateVelocities(btScalar step);

	void			setCenterOfMassTransform(const btTransform& xform);

	void			applyCentralForce(const btVector3& force)
	{
		m_totalForce += force;
	}
    
	const btVector3& getInvInertiaDiagLocal()
	{
		return m_invInertiaLocal;
	};

	void	setInvInertiaDiagLocal(const btVector3& diagInvInertia)
	{
		m_invInertiaLocal = diagInvInertia;
	}

	void	setSleepingThresholds(btScalar linear,btScalar angular)
	{
		m_linearSleepingThreshold = linear;
		m_angularSleepingThreshold = angular;
	}

	void	applyTorque(const btVector3& torque)
	{
		m_totalTorque += torque;
	}
	
	void	applyForce(const btVector3& force, const btVector3& rel_pos) 
	{
		applyCentralForce(force);
		applyTorque(rel_pos.cross(force));
	}
	
	void applyCentralImpulse(const btVector3& impulse)
	{
		m_linearVelocity += impulse * m_inverseMass;
	}
	
  	void applyTorqueImpulse(const btVector3& torque)
	{
			m_angularVelocity += m_invInertiaTensorWorld * torque;
	}
	
	void applyImpulse(const btVector3& impulse, const btVector3& rel_pos) 
	{
		if (m_inverseMass != btScalar(0.))
		{
			applyCentralImpulse(impulse);
			if (m_angularFactor)
			{
				applyTorqueImpulse(rel_pos.cross(impulse)*m_angularFactor);
			}
		}
	}

	//Optimization for the iterative solver: avoid calculating constant terms involving inertia, normal, relative position
	SIMD_FORCE_INLINE void internalApplyImpulse(const btVector3& linearComponent, const btVector3& angularComponent,btScalar impulseMagnitude)
	{
		if (m_inverseMass != btScalar(0.))
		{
			m_linearVelocity += linearComponent*impulseMagnitude;
			if (m_angularFactor)
			{
				m_angularVelocity += angularComponent*impulseMagnitude*m_angularFactor;
			}
		}
	}
	
	void clearForces() 
	{
		m_totalForce.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0));
		m_totalTorque.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0));
	}
	
	void updateInertiaTensor();    
	
	const btPoint3&     getCenterOfMassPosition() const { 
		return m_worldTransform.getOrigin(); 
	}
	btQuaternion getOrientation() const;
	
	const btTransform&  getCenterOfMassTransform() const { 
		return m_worldTransform; 
	}
	const btVector3&   getLinearVelocity() const { 
		return m_linearVelocity; 
	}
	const btVector3&    getAngularVelocity() const { 
		return m_angularVelocity; 
	}
	

	inline void setLinearVelocity(const btVector3& lin_vel)
	{ 
		assert (m_collisionFlags != btCollisionObject::CF_STATIC_OBJECT);
		m_linearVelocity = lin_vel; 
	}

	inline void setAngularVelocity(const btVector3& ang_vel) { 
		assert (m_collisionFlags != btCollisionObject::CF_STATIC_OBJECT);
		{
			m_angularVelocity = ang_vel; 
		}
	}

	btVector3 getVelocityInLocalPoint(const btVector3& rel_pos) const
	{
		//we also calculate lin/ang velocity for kinematic objects
		return m_linearVelocity + m_angularVelocity.cross(rel_pos);

		//for kinematic objects, we could also use use:
		//		return 	(m_worldTransform(rel_pos) - m_interpolationWorldTransform(rel_pos)) / m_kinematicTimeStep;
	}

	void translate(const btVector3& v) 
	{
		m_worldTransform.getOrigin() += v; 
	}

	
	void	getAabb(btVector3& aabbMin,btVector3& aabbMax) const;




	
	SIMD_FORCE_INLINE btScalar computeImpulseDenominator(const btPoint3& pos, const btVector3& normal) const
	{
		btVector3 r0 = pos - getCenterOfMassPosition();

		btVector3 c0 = (r0).cross(normal);

		btVector3 vec = (c0 * getInvInertiaTensorWorld()).cross(r0);

		return m_inverseMass + normal.dot(vec);

	}

	SIMD_FORCE_INLINE btScalar computeAngularImpulseDenominator(const btVector3& axis) const
	{
		btVector3 vec = axis * getInvInertiaTensorWorld();
		return axis.dot(vec);
	}

	SIMD_FORCE_INLINE void	updateDeactivation(btScalar timeStep)
	{
		if ( (getActivationState() == ISLAND_SLEEPING) || (getActivationState() == DISABLE_DEACTIVATION))
			return;

		if ((getLinearVelocity().length2() < m_linearSleepingThreshold*m_linearSleepingThreshold) &&
			(getAngularVelocity().length2() < m_angularSleepingThreshold*m_angularSleepingThreshold))
		{
			m_deactivationTime += timeStep;
		} else
		{
			m_deactivationTime=btScalar(0.);
			setActivationState(0);
		}

	}

	SIMD_FORCE_INLINE bool	wantsSleeping()
	{

		if (getActivationState() == DISABLE_DEACTIVATION)
			return false;

		//disable deactivation
		if (gDisableDeactivation || (gDeactivationTime == btScalar(0.)))
			return false;

		if ( (getActivationState() == ISLAND_SLEEPING) || (getActivationState() == WANTS_DEACTIVATION))
			return true;

		if (m_deactivationTime> gDeactivationTime)
		{
			return true;
		}
		return false;
	}


	
	const btBroadphaseProxy*	getBroadphaseProxy() const
	{
		return m_broadphaseHandle;
	}
	btBroadphaseProxy*	getBroadphaseProxy() 
	{
		return m_broadphaseHandle;
	}
	void	setNewBroadphaseProxy(btBroadphaseProxy* broadphaseProxy)
	{
		m_broadphaseHandle = broadphaseProxy;
	}

	//btMotionState allows to automatic synchronize the world transform for active objects
	btMotionState*	getMotionState()
	{
		return m_optionalMotionState;
	}
	const btMotionState*	getMotionState() const
	{
		return m_optionalMotionState;
	}
	void	setMotionState(btMotionState* motionState)
	{
		m_optionalMotionState = motionState;
		if (m_optionalMotionState)
			motionState->getWorldTransform(m_worldTransform);
	}

	//for experimental overriding of friction/contact solver func
	int	m_contactSolverType;
	int	m_frictionSolverType;

	void	setAngularFactor(btScalar angFac)
	{
		m_angularFactor = angFac;
	}
	btScalar	getAngularFactor() const
	{
		return m_angularFactor;
	}

	//is this rigidbody added to a btCollisionWorld/btDynamicsWorld/btBroadphase?
	bool	isInWorld() const
	{
		return (getBroadphaseProxy() != 0);
	}

	virtual bool checkCollideWithOverride(btCollisionObject* co);

	void addConstraintRef(btTypedConstraint* c);
	void removeConstraintRef(btTypedConstraint* c);

	btTypedConstraint* getConstraintRef(int index)
	{
		return m_constraintRefs[index];
	}

	int getNumConstraintRefs()
	{
		return m_constraintRefs.size();
	}

	int	m_debugBodyId;
};



#endif

