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 #if defined (_WIN32) || defined (__i386__) 17 #define BT_USE_SSE_IN_API 18 #endif 19 20 #include "btConvexHullShape.h" 21 #include "BulletCollision/CollisionShapes/btCollisionMargin.h" 22 23 #include "LinearMath/btQuaternion.h" 24 #include "LinearMath/btSerializer.h" 25 26 btConvexHullShape ::btConvexHullShape (const btScalar* points,int numPoints,int stride) : btPolyhedralConvexAabbCachingShape () 27 { 28 m_shapeType = CONVEX_HULL_SHAPE_PROXYTYPE; 29 m_unscaledPoints.resize(numPoints); 30 31 unsigned char* pointsAddress = (unsigned char*)points; 32 33 for (int i=0;i<numPoints;i++) 34 { 35 btScalar* point = (btScalar*)pointsAddress; 36 m_unscaledPoints[i] = btVector3(point[0], point[1], point[2]); 37 pointsAddress += stride; 38 } 39 40 recalcLocalAabb(); 41 42 } 43 44 45 46 void btConvexHullShape::setLocalScaling(const btVector3& scaling) 47 { 48 m_localScaling = scaling; 49 recalcLocalAabb(); 50 } 51 52 void btConvexHullShape::addPoint(const btVector3& point, bool recalculateLocalAabb) 53 { 54 m_unscaledPoints.push_back(point); 55 if (recalculateLocalAabb) 56 recalcLocalAabb(); 57 58 } 59 60 btVector3 btConvexHullShape::localGetSupportingVertexWithoutMargin(const btVector3& vec)const 61 { 62 btVector3 supVec(btScalar(0.),btScalar(0.),btScalar(0.)); 63 btScalar maxDot = btScalar(-BT_LARGE_FLOAT); 64 65 // Here we take advantage of dot(a, b*c) = dot(a*b, c). Note: This is true mathematically, but not numerically. 66 if( 0 < m_unscaledPoints.size() ) 67 { 68 btVector3 scaled = vec * m_localScaling; 69 int index = (int) scaled.maxDot( &m_unscaledPoints[0], m_unscaledPoints.size(), maxDot); // FIXME: may violate encapsulation of m_unscaledPoints 70 return m_unscaledPoints[index] * m_localScaling; 71 } 72 73 return supVec; 74 } 75 76 void btConvexHullShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const 77 { 78 btScalar newDot; 79 //use 'w' component of supportVerticesOut? 80 { 81 for (int i=0;i<numVectors;i++) 82 { 83 supportVerticesOut[i][3] = btScalar(-BT_LARGE_FLOAT); 84 } 85 } 86 87 for (int j=0;j<numVectors;j++) 88 { 89 btVector3 vec = vectors[j] * m_localScaling; // dot(a*b,c) = dot(a,b*c) 90 if( 0 < m_unscaledPoints.size() ) 91 { 92 int i = (int) vec.maxDot( &m_unscaledPoints[0], m_unscaledPoints.size(), newDot); 93 supportVerticesOut[j] = getScaledPoint(i); 94 supportVerticesOut[j][3] = newDot; 95 } 96 else 97 supportVerticesOut[j][3] = -BT_LARGE_FLOAT; 98 } 99 100 101 102 } 103 104 105 106 btVector3 btConvexHullShape::localGetSupportingVertex(const btVector3& vec)const 107 { 108 btVector3 supVertex = localGetSupportingVertexWithoutMargin(vec); 109 110 if ( getMargin()!=btScalar(0.) ) 111 { 112 btVector3 vecnorm = vec; 113 if (vecnorm .length2() < (SIMD_EPSILON*SIMD_EPSILON)) 114 { 115 vecnorm.setValue(btScalar(-1.),btScalar(-1.),btScalar(-1.)); 116 } 117 vecnorm.normalize(); 118 supVertex+= getMargin() * vecnorm; 119 } 120 return supVertex; 121 } 122 123 124 125 126 127 128 129 130 131 //currently just for debugging (drawing), perhaps future support for algebraic continuous collision detection 132 //Please note that you can debug-draw btConvexHullShape with the Raytracer Demo 133 int btConvexHullShape::getNumVertices() const 134 { 135 return m_unscaledPoints.size(); 136 } 137 138 int btConvexHullShape::getNumEdges() const 139 { 140 return m_unscaledPoints.size(); 141 } 142 143 void btConvexHullShape::getEdge(int i,btVector3& pa,btVector3& pb) const 144 { 145 146 int index0 = i%m_unscaledPoints.size(); 147 int index1 = (i+1)%m_unscaledPoints.size(); 148 pa = getScaledPoint(index0); 149 pb = getScaledPoint(index1); 150 } 151 152 void btConvexHullShape::getVertex(int i,btVector3& vtx) const 153 { 154 vtx = getScaledPoint(i); 155 } 156 157 int btConvexHullShape::getNumPlanes() const 158 { 159 return 0; 160 } 161 162 void btConvexHullShape::getPlane(btVector3& ,btVector3& ,int ) const 163 { 164 165 btAssert(0); 166 } 167 168 //not yet 169 bool btConvexHullShape::isInside(const btVector3& ,btScalar ) const 170 { 171 btAssert(0); 172 return false; 173 } 174 175 ///fills the dataBuffer and returns the struct name (and 0 on failure) 176 const char* btConvexHullShape::serialize(void* dataBuffer, btSerializer* serializer) const 177 { 178 //int szc = sizeof(btConvexHullShapeData); 179 btConvexHullShapeData* shapeData = (btConvexHullShapeData*) dataBuffer; 180 btConvexInternalShape::serialize(&shapeData->m_convexInternalShapeData, serializer); 181 182 int numElem = m_unscaledPoints.size(); 183 shapeData->m_numUnscaledPoints = numElem; 184 #ifdef BT_USE_DOUBLE_PRECISION 185 shapeData->m_unscaledPointsFloatPtr = 0; 186 shapeData->m_unscaledPointsDoublePtr = numElem ? (btVector3Data*)serializer->getUniquePointer((void*)&m_unscaledPoints[0]): 0; 187 #else 188 shapeData->m_unscaledPointsFloatPtr = numElem ? (btVector3Data*)serializer->getUniquePointer((void*)&m_unscaledPoints[0]): 0; 189 shapeData->m_unscaledPointsDoublePtr = 0; 190 #endif 191 192 if (numElem) 193 { 194 int sz = sizeof(btVector3Data); 195 // int sz2 = sizeof(btVector3DoubleData); 196 // int sz3 = sizeof(btVector3FloatData); 197 btChunk* chunk = serializer->allocate(sz,numElem); 198 btVector3Data* memPtr = (btVector3Data*)chunk->m_oldPtr; 199 for (int i=0;i<numElem;i++,memPtr++) 200 { 201 m_unscaledPoints[i].serialize(*memPtr); 202 } 203 serializer->finalizeChunk(chunk,btVector3DataName,BT_ARRAY_CODE,(void*)&m_unscaledPoints[0]); 204 } 205 206 return "btConvexHullShapeData"; 207 } 208 209 void btConvexHullShape::project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const 210 { 211 #if 1 212 minProj = FLT_MAX; 213 maxProj = -FLT_MAX; 214 215 int numVerts = m_unscaledPoints.size(); 216 for(int i=0;i<numVerts;i++) 217 { 218 btVector3 vtx = m_unscaledPoints[i] * m_localScaling; 219 btVector3 pt = trans * vtx; 220 btScalar dp = pt.dot(dir); 221 if(dp < minProj) 222 { 223 minProj = dp; 224 witnesPtMin = pt; 225 } 226 if(dp > maxProj) 227 { 228 maxProj = dp; 229 witnesPtMax=pt; 230 } 231 } 232 #else 233 btVector3 localAxis = dir*trans.getBasis(); 234 witnesPtMin = trans(localGetSupportingVertex(localAxis)); 235 witnesPtMax = trans(localGetSupportingVertex(-localAxis)); 236 237 minProj = witnesPtMin.dot(dir); 238 maxProj = witnesPtMax.dot(dir); 239 #endif 240 241 if(minProj>maxProj) 242 { 243 btSwap(minProj,maxProj); 244 btSwap(witnesPtMin,witnesPtMax); 245 } 246 247 248 } 249 250 251
