btPersistentManifold.h

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/*
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_PERSISTENT_MANIFOLD_H
#define BT_PERSISTENT_MANIFOLD_H
 
 
#include "LinearMath/btVector3.h"
#include "LinearMath/btTransform.h"
#include "btManifoldPoint.h"
class btCollisionObject;
#include "LinearMath/btAlignedAllocator.h"
 
struct btCollisionResult;
 
extern btScalar gContactBreakingThreshold;
 
#ifndef SWIG
class btPersistentManifold;
 
typedef bool (*ContactDestroyedCallback)(void* userPersistentData);
typedef bool (*ContactProcessedCallback)(btManifoldPoint& cp,void* body0,void* body1);
typedef void (*ContactStartedCallback)(btPersistentManifold* const &manifold);
typedef void (*ContactEndedCallback)(btPersistentManifold* const &manifold);
extern ContactDestroyedCallback gContactDestroyedCallback;
extern ContactProcessedCallback gContactProcessedCallback;
extern ContactStartedCallback gContactStartedCallback;
extern ContactEndedCallback gContactEndedCallback;
#endif //SWIG
 
//the enum starts at 1024 to avoid type conflicts with btTypedConstraint
enum btContactManifoldTypes
{
        MIN_CONTACT_MANIFOLD_TYPE = 1024,
        BT_PERSISTENT_MANIFOLD_TYPE
};
 
#define MANIFOLD_CACHE_SIZE 4
 
 
 
//ATTRIBUTE_ALIGNED128( class) btPersistentManifold : public btTypedObject
ATTRIBUTE_ALIGNED16( class) btPersistentManifold : public btTypedObject
{
 
        btManifoldPoint m_pointCache[MANIFOLD_CACHE_SIZE];
 
        const btCollisionObject* m_body0;
        const btCollisionObject* m_body1;
 
        int     m_cachedPoints;
 
        btScalar        m_contactBreakingThreshold;
        btScalar        m_contactProcessingThreshold;
 
        
        int     sortCachedPoints(const btManifoldPoint& pt);
 
        int             findContactPoint(const btManifoldPoint* unUsed, int numUnused,const btManifoldPoint& pt);
 
public:
 
        BT_DECLARE_ALIGNED_ALLOCATOR();
 
        int     m_companionIdA;
        int     m_companionIdB;
 
        int m_index1a;
 
        btPersistentManifold();
 
        btPersistentManifold(const btCollisionObject* body0,const btCollisionObject* body1,int , btScalar contactBreakingThreshold,btScalar contactProcessingThreshold)
                : btTypedObject(BT_PERSISTENT_MANIFOLD_TYPE),
        m_body0(body0),m_body1(body1),m_cachedPoints(0),
                m_contactBreakingThreshold(contactBreakingThreshold),
                m_contactProcessingThreshold(contactProcessingThreshold)
        {
        }
 
        SIMD_FORCE_INLINE const btCollisionObject* getBody0() const { return m_body0;}
        SIMD_FORCE_INLINE const btCollisionObject* getBody1() const { return m_body1;}
 
        void    setBodies(const btCollisionObject* body0,const btCollisionObject* body1)
        {
                m_body0 = body0;
                m_body1 = body1;
        }
 
        void clearUserCache(btManifoldPoint& pt);
 
#ifdef DEBUG_PERSISTENCY
        void    DebugPersistency();
#endif //
        
        SIMD_FORCE_INLINE int   getNumContacts() const { return m_cachedPoints;}
        void setNumContacts(int cachedPoints)
        {
                m_cachedPoints = cachedPoints;
        }
 
 
        SIMD_FORCE_INLINE const btManifoldPoint& getContactPoint(int index) const
        {
                btAssert(index < m_cachedPoints);
                return m_pointCache[index];
        }
 
        SIMD_FORCE_INLINE btManifoldPoint& getContactPoint(int index)
        {
                btAssert(index < m_cachedPoints);
                return m_pointCache[index];
        }
 
        btScalar        getContactBreakingThreshold() const;
 
        btScalar        getContactProcessingThreshold() const
        {
                return m_contactProcessingThreshold;
        }
        
        void setContactBreakingThreshold(btScalar contactBreakingThreshold)
        {
                m_contactBreakingThreshold = contactBreakingThreshold;
        }
 
        void setContactProcessingThreshold(btScalar     contactProcessingThreshold)
        {
                m_contactProcessingThreshold = contactProcessingThreshold;
        }
        
        
 
 
        int getCacheEntry(const btManifoldPoint& newPoint) const;
 
        int addManifoldPoint( const btManifoldPoint& newPoint, bool isPredictive=false);
 
        void removeContactPoint (int index)
        {
                clearUserCache(m_pointCache[index]);
 
                int lastUsedIndex = getNumContacts() - 1;
//              m_pointCache[index] = m_pointCache[lastUsedIndex];
                if(index != lastUsedIndex) 
                {
                        m_pointCache[index] = m_pointCache[lastUsedIndex]; 
                        //get rid of duplicated userPersistentData pointer
                        m_pointCache[lastUsedIndex].m_userPersistentData = 0;
                        m_pointCache[lastUsedIndex].m_appliedImpulse = 0.f;
                        m_pointCache[lastUsedIndex].m_contactPointFlags = 0;
                        m_pointCache[lastUsedIndex].m_appliedImpulseLateral1 = 0.f;
                        m_pointCache[lastUsedIndex].m_appliedImpulseLateral2 = 0.f;
                        m_pointCache[lastUsedIndex].m_lifeTime = 0;
                }
 
                btAssert(m_pointCache[lastUsedIndex].m_userPersistentData==0);
                m_cachedPoints--;
 
                if (gContactEndedCallback && m_cachedPoints == 0)
                {
                        gContactEndedCallback(this);
                }
        }
        void replaceContactPoint(const btManifoldPoint& newPoint, int insertIndex)
        {
                btAssert(validContactDistance(newPoint));
 
#define MAINTAIN_PERSISTENCY 1
#ifdef MAINTAIN_PERSISTENCY
                int lifeTime = m_pointCache[insertIndex].getLifeTime();
                btScalar appliedImpulse = m_pointCache[insertIndex].m_appliedImpulse;
                btScalar appliedLateralImpulse1 = m_pointCache[insertIndex].m_appliedImpulseLateral1;
                btScalar appliedLateralImpulse2 = m_pointCache[insertIndex].m_appliedImpulseLateral2;
 
                bool replacePoint = true;
                if (newPoint.m_contactPointFlags & BT_CONTACT_FLAG_FRICTION_ANCHOR)
                {
                        //   printf("appliedImpulse=%f\n", appliedImpulse);
                        //   printf("appliedLateralImpulse1=%f\n", appliedLateralImpulse1);
                        //   printf("appliedLateralImpulse2=%f\n", appliedLateralImpulse2);
                        //   printf("mu = %f\n", m_pointCache[insertIndex].m_combinedFriction);
                        btScalar mu = m_pointCache[insertIndex].m_combinedFriction;
                        btScalar eps = 0;  //we could allow to enlarge or shrink the tolerance to check against the friction cone a bit, say 1e-7
                        btScalar a = appliedLateralImpulse1 * appliedLateralImpulse1 + appliedLateralImpulse2 * appliedLateralImpulse2;
                        btScalar b = eps + mu * appliedImpulse;
                        b = b * b;
                        replacePoint = (a) > (b);
                }
 
                if (replacePoint)
                {
                        btAssert(lifeTime >= 0);
                        void* cache = m_pointCache[insertIndex].m_userPersistentData;
 
                        m_pointCache[insertIndex] = newPoint;
                        m_pointCache[insertIndex].m_userPersistentData = cache;
                        m_pointCache[insertIndex].m_appliedImpulse = appliedImpulse;
                        m_pointCache[insertIndex].m_appliedImpulseLateral1 = appliedLateralImpulse1;
                        m_pointCache[insertIndex].m_appliedImpulseLateral2 = appliedLateralImpulse2;
                }
 
                m_pointCache[insertIndex].m_lifeTime = lifeTime;
#else
                clearUserCache(m_pointCache[insertIndex]);
                m_pointCache[insertIndex] = newPoint;
 
#endif
        }
 
        bool validContactDistance(const btManifoldPoint& pt) const
        {
                return pt.m_distance1 <= getContactBreakingThreshold();
        }
        void    refreshContactPoints(  const btTransform& trA,const btTransform& trB);
 
        
        SIMD_FORCE_INLINE       void    clearManifold()
        {
                int i;
                for (i=0;i<m_cachedPoints;i++)
                {
                        clearUserCache(m_pointCache[i]);
                }
 
                if (gContactEndedCallback && m_cachedPoints)
                {
                        gContactEndedCallback(this);
                }
                m_cachedPoints = 0;
        }
 
 
 
}
;
 
 
 
 
 
#endif //BT_PERSISTENT_MANIFOLD_H