source: code/trunk/src/bullet/BulletDynamics/ConstraintSolver/btSolverBody.h @ 2743

/*
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 BT_SOLVER_BODY_H
#define BT_SOLVER_BODY_H

class   btRigidBody;
#include "LinearMath/btVector3.h"
#include "LinearMath/btMatrix3x3.h"
#include "BulletDynamics/Dynamics/btRigidBody.h"
#include "LinearMath/btAlignedAllocator.h"
#include "LinearMath/btTransformUtil.h"


///The btSolverBody is an internal datastructure for the constraint solver. Only necessary data is packed to increase cache coherence/performance.
ATTRIBUTE_ALIGNED16 (struct)    btSolverBody
{
        BT_DECLARE_ALIGNED_ALLOCATOR();
        
        btMatrix3x3             m_worldInvInertiaTensor;

        btVector3               m_angularVelocity;
        btVector3               m_linearVelocity;
        btVector3               m_centerOfMassPosition;
        btVector3               m_pushVelocity;
        btVector3               m_turnVelocity;

        float                   m_angularFactor;
        float                   m_invMass;
        float                   m_friction;
        btRigidBody*    m_originalBody;
        
        
        SIMD_FORCE_INLINE void  getVelocityInLocalPoint(const btVector3& rel_pos, btVector3& velocity ) const
        {
                velocity = m_linearVelocity + m_angularVelocity.cross(rel_pos);
        }

        //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_invMass)
                {
                        m_linearVelocity += linearComponent*impulseMagnitude;
                        m_angularVelocity += angularComponent*(impulseMagnitude*m_angularFactor);
                }
        }
        
        SIMD_FORCE_INLINE void internalApplyPushImpulse(const btVector3& linearComponent, const btVector3& angularComponent,btScalar impulseMagnitude)
        {
                if (m_invMass)
                {
                        m_pushVelocity += linearComponent*impulseMagnitude;
                        m_turnVelocity += angularComponent*(impulseMagnitude*m_angularFactor);
                }
        }

        
        void    writebackVelocity()
        {
                if (m_invMass)
                {
                        m_originalBody->setLinearVelocity(m_linearVelocity);
                        m_originalBody->setAngularVelocity(m_angularVelocity);
                        
                        //m_originalBody->setCompanionId(-1);
                }
        }
        

        void    writebackVelocity(btScalar timeStep)
        {
                if (m_invMass)
                {
                        m_originalBody->setLinearVelocity(m_linearVelocity);
                        m_originalBody->setAngularVelocity(m_angularVelocity);
                        
                        //correct the position/orientation based on push/turn recovery
                        btTransform newTransform;
                        btTransformUtil::integrateTransform(m_originalBody->getWorldTransform(),m_pushVelocity,m_turnVelocity,timeStep,newTransform);
                        m_originalBody->setWorldTransform(newTransform);
                        
                        //m_originalBody->setCompanionId(-1);
                }
        }

        void    readVelocity()
        {
                if (m_invMass)
                {
                        m_linearVelocity = m_originalBody->getLinearVelocity();
                        m_angularVelocity = m_originalBody->getAngularVelocity();
                }
        }

        


};

#endif //BT_SOLVER_BODY_H