304 lines
7.5 KiB
C++
304 lines
7.5 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2011 Advanced Micro Devices, Inc. http://bulletphysics.org
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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///This file was written by Erwin Coumans
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///Separating axis rest based on work from Pierre Terdiman, see
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///And contact clipping based on work from Simon Hobbs
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#include "btConvexPolyhedron.h"
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#include "LinearMath/btHashMap.h"
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btConvexPolyhedron::btConvexPolyhedron()
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{
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}
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btConvexPolyhedron::~btConvexPolyhedron()
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{
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}
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inline bool IsAlmostZero(const btVector3& v)
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{
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if(btFabs(v.x())>1e-6 || btFabs(v.y())>1e-6 || btFabs(v.z())>1e-6) return false;
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return true;
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}
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struct btInternalVertexPair
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{
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btInternalVertexPair(short int v0,short int v1)
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:m_v0(v0),
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m_v1(v1)
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{
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if (m_v1>m_v0)
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btSwap(m_v0,m_v1);
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}
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short int m_v0;
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short int m_v1;
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int getHash() const
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{
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return m_v0+(m_v1<<16);
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}
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bool equals(const btInternalVertexPair& other) const
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{
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return m_v0==other.m_v0 && m_v1==other.m_v1;
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}
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};
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struct btInternalEdge
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{
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btInternalEdge()
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:m_face0(-1),
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m_face1(-1)
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{
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}
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short int m_face0;
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short int m_face1;
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};
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//
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#ifdef TEST_INTERNAL_OBJECTS
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bool btConvexPolyhedron::testContainment() const
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{
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for(int p=0;p<8;p++)
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{
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btVector3 LocalPt;
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if(p==0) LocalPt = m_localCenter + btVector3(m_extents[0], m_extents[1], m_extents[2]);
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else if(p==1) LocalPt = m_localCenter + btVector3(m_extents[0], m_extents[1], -m_extents[2]);
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else if(p==2) LocalPt = m_localCenter + btVector3(m_extents[0], -m_extents[1], m_extents[2]);
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else if(p==3) LocalPt = m_localCenter + btVector3(m_extents[0], -m_extents[1], -m_extents[2]);
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else if(p==4) LocalPt = m_localCenter + btVector3(-m_extents[0], m_extents[1], m_extents[2]);
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else if(p==5) LocalPt = m_localCenter + btVector3(-m_extents[0], m_extents[1], -m_extents[2]);
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else if(p==6) LocalPt = m_localCenter + btVector3(-m_extents[0], -m_extents[1], m_extents[2]);
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else if(p==7) LocalPt = m_localCenter + btVector3(-m_extents[0], -m_extents[1], -m_extents[2]);
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for(int i=0;i<m_faces.size();i++)
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{
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const btVector3 Normal(m_faces[i].m_plane[0], m_faces[i].m_plane[1], m_faces[i].m_plane[2]);
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const btScalar d = LocalPt.dot(Normal) + m_faces[i].m_plane[3];
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if(d>0.0f)
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return false;
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}
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}
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return true;
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}
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#endif
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void btConvexPolyhedron::initialize()
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{
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btHashMap<btInternalVertexPair,btInternalEdge> edges;
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btScalar TotalArea = 0.0f;
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m_localCenter.setValue(0, 0, 0);
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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int NbTris = numVertices;
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for(int j=0;j<NbTris;j++)
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{
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int k = (j+1)%numVertices;
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btInternalVertexPair vp(m_faces[i].m_indices[j],m_faces[i].m_indices[k]);
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btInternalEdge* edptr = edges.find(vp);
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btVector3 edge = m_vertices[vp.m_v1]-m_vertices[vp.m_v0];
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edge.normalize();
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bool found = false;
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for (int p=0;p<m_uniqueEdges.size();p++)
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{
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if (IsAlmostZero(m_uniqueEdges[p]-edge) ||
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IsAlmostZero(m_uniqueEdges[p]+edge))
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{
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found = true;
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break;
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}
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}
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if (!found)
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{
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m_uniqueEdges.push_back(edge);
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}
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if (edptr)
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{
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btAssert(edptr->m_face0>=0);
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btAssert(edptr->m_face1<0);
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edptr->m_face1 = i;
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} else
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{
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btInternalEdge ed;
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ed.m_face0 = i;
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edges.insert(vp,ed);
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}
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}
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}
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#ifdef USE_CONNECTED_FACES
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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m_faces[i].m_connectedFaces.resize(numVertices);
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for(int j=0;j<numVertices;j++)
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{
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int k = (j+1)%numVertices;
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btInternalVertexPair vp(m_faces[i].m_indices[j],m_faces[i].m_indices[k]);
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btInternalEdge* edptr = edges.find(vp);
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btAssert(edptr);
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btAssert(edptr->m_face0>=0);
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btAssert(edptr->m_face1>=0);
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int connectedFace = (edptr->m_face0==i)?edptr->m_face1:edptr->m_face0;
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m_faces[i].m_connectedFaces[j] = connectedFace;
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}
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}
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#endif//USE_CONNECTED_FACES
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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int NbTris = numVertices-2;
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const btVector3& p0 = m_vertices[m_faces[i].m_indices[0]];
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for(int j=1;j<=NbTris;j++)
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{
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int k = (j+1)%numVertices;
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const btVector3& p1 = m_vertices[m_faces[i].m_indices[j]];
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const btVector3& p2 = m_vertices[m_faces[i].m_indices[k]];
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btScalar Area = ((p0 - p1).cross(p0 - p2)).length() * 0.5f;
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btVector3 Center = (p0+p1+p2)/3.0f;
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m_localCenter += Area * Center;
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TotalArea += Area;
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}
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}
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m_localCenter /= TotalArea;
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#ifdef TEST_INTERNAL_OBJECTS
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if(1)
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{
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m_radius = FLT_MAX;
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for(int i=0;i<m_faces.size();i++)
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{
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const btVector3 Normal(m_faces[i].m_plane[0], m_faces[i].m_plane[1], m_faces[i].m_plane[2]);
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const btScalar dist = btFabs(m_localCenter.dot(Normal) + m_faces[i].m_plane[3]);
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if(dist<m_radius)
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m_radius = dist;
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}
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btScalar MinX = FLT_MAX;
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btScalar MinY = FLT_MAX;
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btScalar MinZ = FLT_MAX;
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btScalar MaxX = -FLT_MAX;
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btScalar MaxY = -FLT_MAX;
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btScalar MaxZ = -FLT_MAX;
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for(int i=0; i<m_vertices.size(); i++)
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{
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const btVector3& pt = m_vertices[i];
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if(pt.x()<MinX) MinX = pt.x();
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if(pt.x()>MaxX) MaxX = pt.x();
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if(pt.y()<MinY) MinY = pt.y();
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if(pt.y()>MaxY) MaxY = pt.y();
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if(pt.z()<MinZ) MinZ = pt.z();
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if(pt.z()>MaxZ) MaxZ = pt.z();
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}
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mC.setValue(MaxX+MinX, MaxY+MinY, MaxZ+MinZ);
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mE.setValue(MaxX-MinX, MaxY-MinY, MaxZ-MinZ);
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// const btScalar r = m_radius / sqrtf(2.0f);
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const btScalar r = m_radius / sqrtf(3.0f);
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const int LargestExtent = mE.maxAxis();
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const btScalar Step = (mE[LargestExtent]*0.5f - r)/1024.0f;
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m_extents[0] = m_extents[1] = m_extents[2] = r;
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m_extents[LargestExtent] = mE[LargestExtent]*0.5f;
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bool FoundBox = false;
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for(int j=0;j<1024;j++)
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{
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if(testContainment())
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{
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FoundBox = true;
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break;
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}
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m_extents[LargestExtent] -= Step;
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}
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if(!FoundBox)
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{
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m_extents[0] = m_extents[1] = m_extents[2] = r;
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}
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else
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{
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// Refine the box
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const btScalar Step = (m_radius - r)/1024.0f;
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const int e0 = (1<<LargestExtent) & 3;
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const int e1 = (1<<e0) & 3;
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for(int j=0;j<1024;j++)
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{
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const btScalar Saved0 = m_extents[e0];
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const btScalar Saved1 = m_extents[e1];
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m_extents[e0] += Step;
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m_extents[e1] += Step;
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if(!testContainment())
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{
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m_extents[e0] = Saved0;
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m_extents[e1] = Saved1;
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break;
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}
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}
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}
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}
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#endif
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}
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void btConvexPolyhedron::project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const
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{
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minProj = FLT_MAX;
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maxProj = -FLT_MAX;
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int numVerts = m_vertices.size();
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for(int i=0;i<numVerts;i++)
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{
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btVector3 pt = trans * m_vertices[i];
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btScalar dp = pt.dot(dir);
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if(dp < minProj)
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{
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minProj = dp;
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witnesPtMin = pt;
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}
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if(dp > maxProj)
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{
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maxProj = dp;
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witnesPtMax = pt;
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}
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}
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if(minProj>maxProj)
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{
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btSwap(minProj,maxProj);
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btSwap(witnesPtMin,witnesPtMax);
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}
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}
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