source: code/archive/ggz2/src/external/bullet/BulletDynamics/ConstraintSolver/btSolverBody.h @ 10611

/*
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"

///Until we get other contributions, only use SIMD on Windows, when using Visual Studio 2008 or later, and not double precision
#ifdef BT_USE_SSE
#define USE_SIMD 1
#endif //


#ifdef USE_SIMD

struct  btSimdScalar
{
        SIMD_FORCE_INLINE       btSimdScalar()
        {

        }

        SIMD_FORCE_INLINE       btSimdScalar(float      fl)
        :m_vec128 (_mm_set1_ps(fl))
        {
        }

        SIMD_FORCE_INLINE       btSimdScalar(__m128 v128)
                :m_vec128(v128)
        {
        }
        union
        {
                __m128          m_vec128;
                float           m_floats[4];
                int                     m_ints[4];
                btScalar        m_unusedPadding;
        };
        SIMD_FORCE_INLINE       __m128  get128()
        {
                return m_vec128;
        }

        SIMD_FORCE_INLINE       const __m128    get128() const
        {
                return m_vec128;
        }

        SIMD_FORCE_INLINE       void    set128(__m128 v128)
        {
                m_vec128 = v128;
        }

        SIMD_FORCE_INLINE       operator       __m128()       
        { 
                return m_vec128; 
        }
        SIMD_FORCE_INLINE       operator const __m128() const 
        { 
                return m_vec128; 
        }
        
        SIMD_FORCE_INLINE       operator float() const 
        { 
                return m_floats[0]; 
        }

};

///@brief Return the elementwise product of two btSimdScalar
SIMD_FORCE_INLINE btSimdScalar 
operator*(const btSimdScalar& v1, const btSimdScalar& v2) 
{
        return btSimdScalar(_mm_mul_ps(v1.get128(),v2.get128()));
}

///@brief Return the elementwise product of two btSimdScalar
SIMD_FORCE_INLINE btSimdScalar 
operator+(const btSimdScalar& v1, const btSimdScalar& v2) 
{
        return btSimdScalar(_mm_add_ps(v1.get128(),v2.get128()));
}


#else
#define btSimdScalar btScalar
#endif

///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();
        btVector3               m_deltaLinearVelocity;
        btVector3               m_deltaAngularVelocity;
        btScalar                m_angularFactor;
        btScalar                m_invMass;
        btScalar                m_friction;
        btRigidBody*    m_originalBody;
        btVector3               m_pushVelocity;
        //btVector3             m_turnVelocity; 

        
        SIMD_FORCE_INLINE void  getVelocityInLocalPointObsolete(const btVector3& rel_pos, btVector3& velocity ) const
        {
                if (m_originalBody)
                        velocity = m_originalBody->getLinearVelocity()+m_deltaLinearVelocity + (m_originalBody->getAngularVelocity()+m_deltaAngularVelocity).cross(rel_pos);
                else
                        velocity.setValue(0,0,0);
        }

        SIMD_FORCE_INLINE void  getAngularVelocity(btVector3& angVel) const
        {
                if (m_originalBody)
                        angVel = m_originalBody->getAngularVelocity()+m_deltaAngularVelocity;
                else
                        angVel.setValue(0,0,0);
        }


        //Optimization for the iterative solver: avoid calculating constant terms involving inertia, normal, relative position
        SIMD_FORCE_INLINE void applyImpulse(const btVector3& linearComponent, const btVector3& angularComponent,const btScalar impulseMagnitude)
        {
                //if (m_invMass)
                {
                        m_deltaLinearVelocity += linearComponent*impulseMagnitude;
                        m_deltaAngularVelocity += angularComponent*(impulseMagnitude*m_angularFactor);
                }
        }

        
/*
        
        void    writebackVelocity()
        {
                if (m_invMass)
                {
                        m_originalBody->setLinearVelocity(m_originalBody->getLinearVelocity()+ m_deltaLinearVelocity);
                        m_originalBody->setAngularVelocity(m_originalBody->getAngularVelocity()+m_deltaAngularVelocity);
                        
                        //m_originalBody->setCompanionId(-1);
                }
        }
        */

        void    writebackVelocity(btScalar timeStep=0)
        {
                if (m_invMass)
                {
                        m_originalBody->setLinearVelocity(m_originalBody->getLinearVelocity()+m_deltaLinearVelocity);
                        m_originalBody->setAngularVelocity(m_originalBody->getAngularVelocity()+m_deltaAngularVelocity);
                        //m_originalBody->setCompanionId(-1);
                }
        }
        


};

#endif //BT_SOLVER_BODY_H