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PersistentManifold.cpp

/*
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.
*/


#include "PersistentManifold.h"
#include "SimdTransform.h"
#include <assert.h>

float                               gContactBreakingTreshold = 0.02f;
ContactDestroyedCallback      gContactCallback = 0;


PersistentManifold::PersistentManifold()
:m_body0(0),
m_body1(0),
m_cachedPoints (0),
m_index1(0)
{
}


void  PersistentManifold::ClearManifold()
{
      int i;
      for (i=0;i<m_cachedPoints;i++)
      {
            ClearUserCache(m_pointCache[i]);
      }
      m_cachedPoints = 0;
}

#ifdef DEBUG_PERSISTENCY
#include <stdio.h>
void  PersistentManifold::DebugPersistency()
{
      int i;
      printf("DebugPersistency : numPoints %d\n",m_cachedPoints);
      for (i=0;i<m_cachedPoints;i++)
      {
            printf("m_pointCache[%d].m_userPersistentData = %x\n",i,m_pointCache[i].m_userPersistentData);
      }
}
#endif //DEBUG_PERSISTENCY

void PersistentManifold::ClearUserCache(ManifoldPoint& pt)
{

      void* oldPtr = pt.m_userPersistentData;
      if (oldPtr)
      {
#ifdef DEBUG_PERSISTENCY
            int i;
            int occurance = 0;
            for (i=0;i<m_cachedPoints;i++)
            {
                  if (m_pointCache[i].m_userPersistentData == oldPtr)
                  {
                        occurance++;
                        if (occurance>1)
                              printf("error in ClearUserCache\n");
                  }
            }
            assert(occurance<=0);
#endif //DEBUG_PERSISTENCY

            if (pt.m_userPersistentData && gContactCallback)
            {
                  (*gContactCallback)(pt.m_userPersistentData);
                  pt.m_userPersistentData = 0;
            }
            
#ifdef DEBUG_PERSISTENCY
            DebugPersistency();
#endif
      }

      
}




00095 int PersistentManifold::SortCachedPoints(const ManifoldPoint& pt) 
{

            //calculate 4 possible cases areas, and take biggest area

            SimdScalar res0,res1,res2,res3;

            {
                  SimdVector3 a0 = pt.m_localPointA-m_pointCache[1].m_localPointA;
                  SimdVector3 b0 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
                  SimdVector3 cross = a0.cross(b0);
                  res0 = cross.length2();
            }
            {
                  SimdVector3 a1 = pt.m_localPointA-m_pointCache[0].m_localPointA;
                  SimdVector3 b1 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA;
                  SimdVector3 cross = a1.cross(b1);
                  res1 = cross.length2();
            }
            {
                  SimdVector3 a2 = pt.m_localPointA-m_pointCache[0].m_localPointA;
                  SimdVector3 b2 = m_pointCache[3].m_localPointA-m_pointCache[1].m_localPointA;
                  SimdVector3 cross = a2.cross(b2);
                  res2 = cross.length2();
            }
            {
                  SimdVector3 a3 = pt.m_localPointA-m_pointCache[0].m_localPointA;
                  SimdVector3 b3 = m_pointCache[2].m_localPointA-m_pointCache[1].m_localPointA;
                  SimdVector3 cross = a3.cross(b3);
                  res3 = cross.length2();
            }

            SimdVector4 maxvec(res0,res1,res2,res3);
            int biggestarea = maxvec.closestAxis4();

            return biggestarea;


}



int PersistentManifold::GetCacheEntry(const ManifoldPoint& newPoint) const
{
      SimdScalar shortestDist =  GetContactBreakingTreshold() * GetContactBreakingTreshold();
      int size = GetNumContacts();
      int nearestPoint = -1;
      for( int i = 0; i < size; i++ )
      {
            const ManifoldPoint &mp = m_pointCache[i];

            SimdVector3 diffA =  mp.m_localPointA- newPoint.m_localPointA;
            const SimdScalar distToManiPoint = diffA.dot(diffA);
            if( distToManiPoint < shortestDist )
            {
                  shortestDist = distToManiPoint;
                  nearestPoint = i;
            }
      }
      return nearestPoint;
}

void PersistentManifold::AddManifoldPoint(const ManifoldPoint& newPoint)
{
      assert(ValidContactDistance(newPoint));

      int insertIndex = GetNumContacts();
      if (insertIndex == MANIFOLD_CACHE_SIZE)
      {
#if MANIFOLD_CACHE_SIZE >= 4
            //sort cache so best points come first, based on area
            insertIndex = SortCachedPoints(newPoint);
#else
            insertIndex = 0;
#endif

            
      } else
      {
            m_cachedPoints++;

            
      }
      ReplaceContactPoint(newPoint,insertIndex);
}

00181 float PersistentManifold::GetContactBreakingTreshold() const
{
      return gContactBreakingTreshold;
}

00186 void PersistentManifold::RefreshContactPoints(const SimdTransform& trA,const SimdTransform& trB)
{
      int i;

      /// first refresh worldspace positions and distance
      for (i=GetNumContacts()-1;i>=0;i--)
      {
            ManifoldPoint &manifoldPoint = m_pointCache[i];
            manifoldPoint.m_positionWorldOnA = trA( manifoldPoint.m_localPointA );
            manifoldPoint.m_positionWorldOnB = trB( manifoldPoint.m_localPointB );
            manifoldPoint.m_distance1 = (manifoldPoint.m_positionWorldOnA -  manifoldPoint.m_positionWorldOnB).dot(manifoldPoint.m_normalWorldOnB);
            manifoldPoint.m_lifeTime++;
      }

      /// then 
      SimdScalar distance2d;
      SimdVector3 projectedDifference,projectedPoint;
      for (i=GetNumContacts()-1;i>=0;i--)
      {
            
            ManifoldPoint &manifoldPoint = m_pointCache[i];
            //contact becomes invalid when signed distance exceeds margin (projected on contactnormal direction)
            if (!ValidContactDistance(manifoldPoint))
            {
                  RemoveContactPoint(i);
            } else
            {
                  //contact also becomes invalid when relative movement orthogonal to normal exceeds margin
                  projectedPoint = manifoldPoint.m_positionWorldOnA - manifoldPoint.m_normalWorldOnB * manifoldPoint.m_distance1;
                  projectedDifference = manifoldPoint.m_positionWorldOnB - projectedPoint;
                  distance2d = projectedDifference.dot(projectedDifference);
                  if (distance2d  > GetContactBreakingTreshold()*GetContactBreakingTreshold() )
                  {
                        RemoveContactPoint(i);
                  }
            }
      }
#ifdef DEBUG_PERSISTENCY
      DebugPersistency();
#endif //
}






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