303 lines
7.8 KiB
C++
303 lines
7.8 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)
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LocalPt = m_localCenter + btVector3(m_extents[0], m_extents[1], m_extents[2]);
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else if (p == 1)
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LocalPt = m_localCenter + btVector3(m_extents[0], m_extents[1], -m_extents[2]);
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else if (p == 2)
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LocalPt = m_localCenter + btVector3(m_extents[0], -m_extents[1], m_extents[2]);
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else if (p == 3)
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LocalPt = m_localCenter + btVector3(m_extents[0], -m_extents[1], -m_extents[2]);
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else if (p == 4)
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LocalPt = m_localCenter + btVector3(-m_extents[0], m_extents[1], m_extents[2]);
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else if (p == 5)
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LocalPt = m_localCenter + btVector3(-m_extents[0], m_extents[1], -m_extents[2]);
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else if (p == 6)
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LocalPt = m_localCenter + btVector3(-m_extents[0], -m_extents[1], m_extents[2]);
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else if (p == 7)
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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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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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}
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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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initialize2();
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}
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void btConvexPolyhedron::initialize2()
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{
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m_localCenter.setValue(0, 0, 0);
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btScalar TotalArea = 0.0f;
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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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