src/BulletCollision/CollisionShapes/btShapeHull.cpp

   1 /*
   2 Bullet Continuous Collision Detection and Physics Library
   3 Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org
   4
   5 This software is provided 'as-is', without any express or implied warranty.
   6 In no event will the authors be held liable for any damages arising from the use of this software.
   7 Permission is granted to anyone to use this software for any purpose,
   8 including commercial applications, and to alter it and redistribute it freely,
   9 subject to the following restrictions:
  10
  11 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.
  12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
  13 3. This notice may not be removed or altered from any source distribution.
  14 */
  15
  16 //btShapeHull was implemented by John McCutchan.
  17
  18
  19 #include "btShapeHull.h"
  20 #include "LinearMath/btConvexHull.h"
  21
  22 #define NUM_UNITSPHERE_POINTS 42
  23
  24 btShapeHull::btShapeHull (const btConvexShape* shape)
  25 {
  26         m_shape = shape;
  27         m_vertices.clear ();
  28         m_indices.clear();
  29         m_numIndices = 0;
  30 }
  31
  32 btShapeHull::~btShapeHull ()
  33 {
  34         m_indices.clear();
  35         m_vertices.clear ();
  36 }
  37
  38 bool
  39 btShapeHull::buildHull (btScalar /*margin*/)
  40 {
  41         int numSampleDirections = NUM_UNITSPHERE_POINTS;
  42         {
  43                 int numPDA = m_shape->getNumPreferredPenetrationDirections();
  44                 if (numPDA)
  45                 {
  46                         for (int i=0;i<numPDA;i++)
  47                         {
  48                                 btVector3 norm;
  49                                 m_shape->getPreferredPenetrationDirection(i,norm);
  50                                 getUnitSpherePoints()[numSampleDirections] = norm;
  51                                 numSampleDirections++;
  52                         }
  53                 }
  54         }
  55
  56         btVector3 supportPoints[NUM_UNITSPHERE_POINTS+MAX_PREFERRED_PENETRATION_DIRECTIONS*2];
  57         int i;
  58         for (i = 0; i < numSampleDirections; i++)
  59         {
  60                 supportPoints[i] = m_shape->localGetSupportingVertex(getUnitSpherePoints()[i]);
  61         }
  62
  63         HullDesc hd;
  64         hd.mFlags = QF_TRIANGLES;
  65         hd.mVcount = static_cast<unsigned int>(numSampleDirections);
  66
  67 #ifdef BT_USE_DOUBLE_PRECISION
  68         hd.mVertices = &supportPoints[0];
  69         hd.mVertexStride = sizeof(btVector3);
  70 #else
  71         hd.mVertices = &supportPoints[0];
  72         hd.mVertexStride = sizeof (btVector3);
  73 #endif
  74
  75         HullLibrary hl;
  76         HullResult hr;
  77         if (hl.CreateConvexHull (hd, hr) == QE_FAIL)
  78         {
  79                 return false;
  80         }
  81
  82         m_vertices.resize (static_cast<int>(hr.mNumOutputVertices));
  83
  84
  85         for (i = 0; i < static_cast<int>(hr.mNumOutputVertices); i++)
  86         {
  87                 m_vertices[i] = hr.m_OutputVertices[i];
  88         }
  89         m_numIndices = hr.mNumIndices;
  90         m_indices.resize(static_cast<int>(m_numIndices));
  91         for (i = 0; i < static_cast<int>(m_numIndices); i++)
  92         {
  93                 m_indices[i] = hr.m_Indices[i];
  94         }
  95
  96         // free temporary hull result that we just copied
  97         hl.ReleaseResult (hr);
  98
  99         return true;
 100 }
 101
 102 int
 103 btShapeHull::numTriangles () const
 104 {
 105         return static_cast<int>(m_numIndices / 3);
 106 }
 107
 108 int
 109 btShapeHull::numVertices () const
 110 {
 111         return m_vertices.size ();
 112 }
 113
 114 int
 115 btShapeHull::numIndices () const
 116 {
 117         return static_cast<int>(m_numIndices);
 118 }
 119
 120
 121 btVector3* btShapeHull::getUnitSpherePoints()
 122 {
 123         static btVector3 sUnitSpherePoints[NUM_UNITSPHERE_POINTS+MAX_PREFERRED_PENETRATION_DIRECTIONS*2] =
 124         {
 125                 btVector3(btScalar(0.000000) , btScalar(-0.000000),btScalar(-1.000000)),
 126                 btVector3(btScalar(0.723608) , btScalar(-0.525725),btScalar(-0.447219)),
 127                 btVector3(btScalar(-0.276388) , btScalar(-0.850649),btScalar(-0.447219)),
 128                 btVector3(btScalar(-0.894426) , btScalar(-0.000000),btScalar(-0.447216)),
 129                 btVector3(btScalar(-0.276388) , btScalar(0.850649),btScalar(-0.447220)),
 130                 btVector3(btScalar(0.723608) , btScalar(0.525725),btScalar(-0.447219)),
 131                 btVector3(btScalar(0.276388) , btScalar(-0.850649),btScalar(0.447220)),
 132                 btVector3(btScalar(-0.723608) , btScalar(-0.525725),btScalar(0.447219)),
 133                 btVector3(btScalar(-0.723608) , btScalar(0.525725),btScalar(0.447219)),
 134                 btVector3(btScalar(0.276388) , btScalar(0.850649),btScalar(0.447219)),
 135                 btVector3(btScalar(0.894426) , btScalar(0.000000),btScalar(0.447216)),
 136                 btVector3(btScalar(-0.000000) , btScalar(0.000000),btScalar(1.000000)),
 137                 btVector3(btScalar(0.425323) , btScalar(-0.309011),btScalar(-0.850654)),
 138                 btVector3(btScalar(-0.162456) , btScalar(-0.499995),btScalar(-0.850654)),
 139                 btVector3(btScalar(0.262869) , btScalar(-0.809012),btScalar(-0.525738)),
 140                 btVector3(btScalar(0.425323) , btScalar(0.309011),btScalar(-0.850654)),
 141                 btVector3(btScalar(0.850648) , btScalar(-0.000000),btScalar(-0.525736)),
 142                 btVector3(btScalar(-0.525730) , btScalar(-0.000000),btScalar(-0.850652)),
 143                 btVector3(btScalar(-0.688190) , btScalar(-0.499997),btScalar(-0.525736)),
 144                 btVector3(btScalar(-0.162456) , btScalar(0.499995),btScalar(-0.850654)),
 145                 btVector3(btScalar(-0.688190) , btScalar(0.499997),btScalar(-0.525736)),
 146                 btVector3(btScalar(0.262869) , btScalar(0.809012),btScalar(-0.525738)),
 147                 btVector3(btScalar(0.951058) , btScalar(0.309013),btScalar(0.000000)),
 148                 btVector3(btScalar(0.951058) , btScalar(-0.309013),btScalar(0.000000)),
 149                 btVector3(btScalar(0.587786) , btScalar(-0.809017),btScalar(0.000000)),
 150                 btVector3(btScalar(0.000000) , btScalar(-1.000000),btScalar(0.000000)),
 151                 btVector3(btScalar(-0.587786) , btScalar(-0.809017),btScalar(0.000000)),
 152                 btVector3(btScalar(-0.951058) , btScalar(-0.309013),btScalar(-0.000000)),
 153                 btVector3(btScalar(-0.951058) , btScalar(0.309013),btScalar(-0.000000)),
 154                 btVector3(btScalar(-0.587786) , btScalar(0.809017),btScalar(-0.000000)),
 155                 btVector3(btScalar(-0.000000) , btScalar(1.000000),btScalar(-0.000000)),
 156                 btVector3(btScalar(0.587786) , btScalar(0.809017),btScalar(-0.000000)),
 157                 btVector3(btScalar(0.688190) , btScalar(-0.499997),btScalar(0.525736)),
 158                 btVector3(btScalar(-0.262869) , btScalar(-0.809012),btScalar(0.525738)),
 159                 btVector3(btScalar(-0.850648) , btScalar(0.000000),btScalar(0.525736)),
 160                 btVector3(btScalar(-0.262869) , btScalar(0.809012),btScalar(0.525738)),
 161                 btVector3(btScalar(0.688190) , btScalar(0.499997),btScalar(0.525736)),
 162                 btVector3(btScalar(0.525730) , btScalar(0.000000),btScalar(0.850652)),
 163                 btVector3(btScalar(0.162456) , btScalar(-0.499995),btScalar(0.850654)),
 164                 btVector3(btScalar(-0.425323) , btScalar(-0.309011),btScalar(0.850654)),
 165                 btVector3(btScalar(-0.425323) , btScalar(0.309011),btScalar(0.850654)),
 166                 btVector3(btScalar(0.162456) , btScalar(0.499995),btScalar(0.850654))
 167         };
 168         return sUnitSpherePoints;
 169 }
 170