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AxisSweep3.cpp

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


//
// AxisSweep3
//
// Copyright (c) 2006 Simon Hobbs
//
// 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 "AxisSweep3.h"

#include <assert.h>

BroadphaseProxy*  AxisSweep3::CreateProxy(  const SimdVector3& min,  const SimdVector3& max,int shapeType,void* userPtr )
{
            unsigned short handleId = AddHandle(min,max, userPtr);
            
            Handle* handle = GetHandle(handleId);
            return handle;
}

void  AxisSweep3::DestroyProxy(BroadphaseProxy* proxy)
{
      Handle* handle = static_cast<Handle*>(proxy);
      RemoveHandle(handle->m_handleId);
}

void  AxisSweep3::SetAabb(BroadphaseProxy* proxy,const SimdVector3& aabbMin,const SimdVector3& aabbMax)
{
      Handle* handle = static_cast<Handle*>(proxy);
      UpdateHandle(handle->m_handleId,aabbMin,aabbMax);
}






AxisSweep3::AxisSweep3(const SimdPoint3& worldAabbMin,const SimdPoint3& worldAabbMax, int maxHandles, int maxOverlaps)
{
      //assert(bounds.HasVolume());

      // 1 handle is reserved as sentinel
      assert(maxHandles > 1 && maxHandles < 32767);

      // doesn't need this limit right now, but I may want to use unsigned short indexes into overlaps array
      assert(maxOverlaps > 0 && maxOverlaps < 65536);

      // init bounds
      m_worldAabbMin = worldAabbMin;
      m_worldAabbMax = worldAabbMax;

      SimdVector3 aabbSize = m_worldAabbMax - m_worldAabbMin;

      m_quantize = SimdVector3(65535.0f,65535.0f,65535.0f) / aabbSize;

      // allocate handles buffer and put all handles on free list
      m_pHandles = new Handle[maxHandles];
      m_maxHandles = maxHandles;
      m_numHandles = 0;

      // handle 0 is reserved as the null index, and is also used as the sentinel
      m_firstFreeHandle = 1;
      {
            for (int i = m_firstFreeHandle; i < maxHandles; i++)
                  m_pHandles[i].SetNextFree(i + 1);
            m_pHandles[maxHandles - 1].SetNextFree(0);
      }

      {
      // allocate edge buffers
      for (int i = 0; i < 3; i++)
            m_pEdges[i] = new Edge[maxHandles * 2];
      }
      //removed overlap management

      // make boundary sentinels
      
      m_pHandles[0].m_clientObject = 0;

      for (int axis = 0; axis < 3; axis++)
      {
            m_pHandles[0].m_minEdges[axis] = 0;
            m_pHandles[0].m_maxEdges[axis] = 1;

            m_pEdges[axis][0].m_pos = 0;
            m_pEdges[axis][0].m_handle = 0;
            m_pEdges[axis][1].m_pos = 0xffff;
            m_pEdges[axis][1].m_handle = 0;
      }
}

AxisSweep3::~AxisSweep3()
{
      
      for (int i = 2; i >= 0; i--)
            delete[] m_pEdges[i];
      delete[] m_pHandles;
}

void AxisSweep3::Quantize(unsigned short* out, const SimdPoint3& point, int isMax) const
{
      SimdPoint3 clampedPoint(point);
      /*
      if (isMax)
            clampedPoint += SimdVector3(10,10,10);
      else
      {
            clampedPoint -= SimdVector3(10,10,10);
      }
      */


      clampedPoint.setMax(m_worldAabbMin);
      clampedPoint.setMin(m_worldAabbMax);

      SimdVector3 v = (clampedPoint - m_worldAabbMin) * m_quantize;
      out[0] = (unsigned short)(((int)v.getX() & 0xfffc) | isMax);
      out[1] = (unsigned short)(((int)v.getY() & 0xfffc) | isMax);
      out[2] = (unsigned short)(((int)v.getZ() & 0xfffc) | isMax);
      
}



unsigned short AxisSweep3::AllocHandle()
{
      assert(m_firstFreeHandle);

      unsigned short handle = m_firstFreeHandle;
      m_firstFreeHandle = GetHandle(handle)->GetNextFree();
      m_numHandles++;

      return handle;
}

void AxisSweep3::FreeHandle(unsigned short handle)
{
      assert(handle > 0 && handle < m_maxHandles);

      GetHandle(handle)->SetNextFree(m_firstFreeHandle);
      m_firstFreeHandle = handle;

      m_numHandles--;
}



unsigned short AxisSweep3::AddHandle(const SimdPoint3& aabbMin,const SimdPoint3& aabbMax, void* pOwner)
{
      // quantize the bounds
      unsigned short min[3], max[3];
      Quantize(min, aabbMin, 0);
      Quantize(max, aabbMax, 1);

      // allocate a handle
      unsigned short handle = AllocHandle();
      assert(handle!= 0xcdcd);

      Handle* pHandle = GetHandle(handle);
      

      pHandle->m_handleId = handle;
      //pHandle->m_pOverlaps = 0;
      pHandle->m_clientObject = pOwner;

      // compute current limit of edge arrays
      int limit = m_numHandles * 2;

      // insert new edges just inside the max boundary edge
      for (int axis = 0; axis < 3; axis++)
      {
            m_pHandles[0].m_maxEdges[axis] += 2;

            m_pEdges[axis][limit + 1] = m_pEdges[axis][limit - 1];

            m_pEdges[axis][limit - 1].m_pos = min[axis];
            m_pEdges[axis][limit - 1].m_handle = handle;

            m_pEdges[axis][limit].m_pos = max[axis];
            m_pEdges[axis][limit].m_handle = handle;

            pHandle->m_minEdges[axis] = limit - 1;
            pHandle->m_maxEdges[axis] = limit;
      }

      // now sort the new edges to their correct position
      SortMinDown(0, pHandle->m_minEdges[0], false);
      SortMaxDown(0, pHandle->m_maxEdges[0], false);
      SortMinDown(1, pHandle->m_minEdges[1], false);
      SortMaxDown(1, pHandle->m_maxEdges[1], false);
      SortMinDown(2, pHandle->m_minEdges[2], true);
      SortMaxDown(2, pHandle->m_maxEdges[2], true);

      //PrintAxis(1);

      return handle;
}


void AxisSweep3::RemoveHandle(unsigned short handle)
{
      Handle* pHandle = GetHandle(handle);

      RemoveOverlappingPairsContainingProxy(pHandle);


      // compute current limit of edge arrays
      int limit = m_numHandles * 2;
      int axis;

      for (axis = 0;axis<3;axis++)
      {
            Edge* pEdges = m_pEdges[axis];
            int maxEdge= pHandle->m_maxEdges[axis];
            pEdges[maxEdge].m_pos = 0xffff;
            int minEdge = pHandle->m_minEdges[axis];
            pEdges[minEdge].m_pos = 0xffff;
      }

      // remove the edges by sorting them up to the end of the list
      for ( axis = 0; axis < 3; axis++)
      {
            Edge* pEdges = m_pEdges[axis];
            int max = pHandle->m_maxEdges[axis];
            pEdges[max].m_pos = 0xffff;

            SortMaxUp(axis,max,false);
            
            int i = pHandle->m_minEdges[axis];
            pEdges[i].m_pos = 0xffff;

            SortMinUp(axis,i,false);

            pEdges[limit-1].m_handle = 0;
            pEdges[limit-1].m_pos = 0xffff;

      }

      // free the handle
      FreeHandle(handle);

      
}

bool AxisSweep3::TestOverlap(int ignoreAxis,const Handle* pHandleA, const Handle* pHandleB)
{
      //optimization 1: check the array index (memory address), instead of the m_pos

      for (int axis = 0; axis < 3; axis++)
      { 
            if (axis != ignoreAxis)
            {
                  if (pHandleA->m_maxEdges[axis] < pHandleB->m_minEdges[axis] || 
                        pHandleB->m_maxEdges[axis] < pHandleA->m_minEdges[axis]) 
                  { 
                        return false; 
                  } 
            }
      } 

      //optimization 2: only 2 axis need to be tested

      /*for (int axis = 0; axis < 3; axis++)
      {
            if (m_pEdges[axis][pHandleA->m_maxEdges[axis]].m_pos < m_pEdges[axis][pHandleB->m_minEdges[axis]].m_pos ||
                  m_pEdges[axis][pHandleB->m_maxEdges[axis]].m_pos < m_pEdges[axis][pHandleA->m_minEdges[axis]].m_pos)
            {
                  return false;
            }
      }
      */

      return true;
}

void AxisSweep3::UpdateHandle(unsigned short handle, const SimdPoint3& aabbMin,const SimdPoint3& aabbMax)
{
//    assert(bounds.IsFinite());
      //assert(bounds.HasVolume());

      Handle* pHandle = GetHandle(handle);

      // quantize the new bounds
      unsigned short min[3], max[3];
      Quantize(min, aabbMin, 0);
      Quantize(max, aabbMax, 1);

      // update changed edges
      for (int axis = 0; axis < 3; axis++)
      {
            unsigned short emin = pHandle->m_minEdges[axis];
            unsigned short emax = pHandle->m_maxEdges[axis];

            int dmin = (int)min[axis] - (int)m_pEdges[axis][emin].m_pos;
            int dmax = (int)max[axis] - (int)m_pEdges[axis][emax].m_pos;

            m_pEdges[axis][emin].m_pos = min[axis];
            m_pEdges[axis][emax].m_pos = max[axis];

            // expand (only adds overlaps)
            if (dmin < 0)
                  SortMinDown(axis, emin);

            if (dmax > 0)
                  SortMaxUp(axis, emax);

            // shrink (only removes overlaps)
            if (dmin > 0)
                  SortMinUp(axis, emin);

            if (dmax < 0)
                  SortMaxDown(axis, emax);
      }

      //PrintAxis(1);
}

// sorting a min edge downwards can only ever *add* overlaps
void AxisSweep3::SortMinDown(int axis, unsigned short edge, bool updateOverlaps)
{
      Edge* pEdge = m_pEdges[axis] + edge;
      Edge* pPrev = pEdge - 1;
      Handle* pHandleEdge = GetHandle(pEdge->m_handle);

      while (pEdge->m_pos < pPrev->m_pos)
      {
            Handle* pHandlePrev = GetHandle(pPrev->m_handle);

            if (pPrev->IsMax())
            {
                  // if previous edge is a maximum check the bounds and add an overlap if necessary
                  if (updateOverlaps && TestOverlap(axis,pHandleEdge, pHandlePrev))
                  {
                        AddOverlappingPair(pHandleEdge,pHandlePrev);

                        //AddOverlap(pEdge->m_handle, pPrev->m_handle);

                  }

                  // update edge reference in other handle
                  pHandlePrev->m_maxEdges[axis]++;
            }
            else
                  pHandlePrev->m_minEdges[axis]++;

            pHandleEdge->m_minEdges[axis]--;

            // swap the edges
            Edge swap = *pEdge;
            *pEdge = *pPrev;
            *pPrev = swap;

            // decrement
            pEdge--;
            pPrev--;
      }
}

// sorting a min edge upwards can only ever *remove* overlaps
void AxisSweep3::SortMinUp(int axis, unsigned short edge, bool updateOverlaps)
{
      Edge* pEdge = m_pEdges[axis] + edge;
      Edge* pNext = pEdge + 1;
      Handle* pHandleEdge = GetHandle(pEdge->m_handle);

      while (pEdge->m_pos > pNext->m_pos)
      {
            Handle* pHandleNext = GetHandle(pNext->m_handle);

            if (pNext->IsMax())
            {
                  // if next edge is maximum remove any overlap between the two handles
                  if (updateOverlaps)
                  {
                        Handle* handle0 = GetHandle(pEdge->m_handle);
                        Handle* handle1 = GetHandle(pNext->m_handle);
                        BroadphasePair* pair = FindPair(handle0,handle1);
                        //assert(pair);
                        if (pair)
                        {
                              RemoveOverlappingPair(*pair);
                        }
                  }

                  // update edge reference in other handle
                  pHandleNext->m_maxEdges[axis]--;
            }
            else
                  pHandleNext->m_minEdges[axis]--;

            pHandleEdge->m_minEdges[axis]++;

            // swap the edges
            Edge swap = *pEdge;
            *pEdge = *pNext;
            *pNext = swap;

            // increment
            pEdge++;
            pNext++;
      }
}

// sorting a max edge downwards can only ever *remove* overlaps
void AxisSweep3::SortMaxDown(int axis, unsigned short edge, bool updateOverlaps)
{
      Edge* pEdge = m_pEdges[axis] + edge;
      Edge* pPrev = pEdge - 1;
      Handle* pHandleEdge = GetHandle(pEdge->m_handle);

      while (pEdge->m_pos < pPrev->m_pos)
      {
            Handle* pHandlePrev = GetHandle(pPrev->m_handle);

            if (!pPrev->IsMax())
            {
                  // if previous edge was a minimum remove any overlap between the two handles
                  if (updateOverlaps)
                  {
                        Handle* handle0 = GetHandle(pEdge->m_handle);
                        Handle* handle1 = GetHandle(pPrev->m_handle);
                        BroadphasePair* pair = FindPair(handle0,handle1);
                        //assert(pair);

                        if (pair)
                        {
                              RemoveOverlappingPair(*pair);
                        }
                  }

                  // update edge reference in other handle
                  pHandlePrev->m_minEdges[axis]++;;
            }
            else
                  pHandlePrev->m_maxEdges[axis]++;

            pHandleEdge->m_maxEdges[axis]--;

            // swap the edges
            Edge swap = *pEdge;
            *pEdge = *pPrev;
            *pPrev = swap;

            // decrement
            pEdge--;
            pPrev--;
      }
}

// sorting a max edge upwards can only ever *add* overlaps
void AxisSweep3::SortMaxUp(int axis, unsigned short edge, bool updateOverlaps)
{
      Edge* pEdge = m_pEdges[axis] + edge;
      Edge* pNext = pEdge + 1;
      Handle* pHandleEdge = GetHandle(pEdge->m_handle);

      while (pEdge->m_pos > pNext->m_pos)
      {
            Handle* pHandleNext = GetHandle(pNext->m_handle);

            if (!pNext->IsMax())
            {
                  // if next edge is a minimum check the bounds and add an overlap if necessary
                  if (updateOverlaps && TestOverlap(axis, pHandleEdge, pHandleNext))
                  {
                        Handle* handle0 = GetHandle(pEdge->m_handle);
                        Handle* handle1 = GetHandle(pNext->m_handle);
                        AddOverlappingPair(handle0,handle1);
                  }

                  // update edge reference in other handle
                  pHandleNext->m_minEdges[axis]--;
            }
            else
                  pHandleNext->m_maxEdges[axis]--;

            pHandleEdge->m_maxEdges[axis]++;

            // swap the edges
            Edge swap = *pEdge;
            *pEdge = *pNext;
            *pNext = swap;

            // increment
            pEdge++;
            pNext++;
      }
}

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