1 2 #if 0 3 /* 4 Bullet Continuous Collision Detection and Physics Library 5 Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/ 6 7 This software is provided 'as-is', without any express or implied warranty. 8 In no event will the authors be held liable for any damages arising from the use of this software. 9 Permission is granted to anyone to use this software for any purpose, 10 including commercial applications, and to alter it and redistribute it freely, 11 subject to the following restrictions: 12 13 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. 14 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 15 3. This notice may not be removed or altered from any source distribution. 16 */ 17 18 #include "b3ContactCache.h" 19 #include "Bullet3Common/b3Transform.h" 20 21 #include "Bullet3Collision/NarrowPhaseCollision/shared/b3Contact4Data.h" 22 23 b3Scalar gContactBreakingThreshold = b3Scalar(0.02); 24 25 ///gContactCalcArea3Points will approximate the convex hull area using 3 points 26 ///when setting it to false, it will use 4 points to compute the area: it is more accurate but slower 27 bool gContactCalcArea3Points = true; 28 29 30 31 32 static inline b3Scalar calcArea4Points(const b3Vector3 &p0,const b3Vector3 &p1,const b3Vector3 &p2,const b3Vector3 &p3) 33 { 34 // It calculates possible 3 area constructed from random 4 points and returns the biggest one. 35 36 b3Vector3 a[3],b[3]; 37 a[0] = p0 - p1; 38 a[1] = p0 - p2; 39 a[2] = p0 - p3; 40 b[0] = p2 - p3; 41 b[1] = p1 - p3; 42 b[2] = p1 - p2; 43 44 //todo: Following 3 cross production can be easily optimized by SIMD. 45 b3Vector3 tmp0 = a[0].cross(b[0]); 46 b3Vector3 tmp1 = a[1].cross(b[1]); 47 b3Vector3 tmp2 = a[2].cross(b[2]); 48 49 return b3Max(b3Max(tmp0.length2(),tmp1.length2()),tmp2.length2()); 50 } 51 #if 0 52 53 //using localPointA for all points 54 int b3ContactCache::sortCachedPoints(const b3Vector3& pt) 55 { 56 //calculate 4 possible cases areas, and take biggest area 57 //also need to keep 'deepest' 58 59 int maxPenetrationIndex = -1; 60 #define KEEP_DEEPEST_POINT 1 61 #ifdef KEEP_DEEPEST_POINT 62 b3Scalar maxPenetration = pt.getDistance(); 63 for (int i=0;i<4;i++) 64 { 65 if (m_pointCache[i].getDistance() < maxPenetration) 66 { 67 maxPenetrationIndex = i; 68 maxPenetration = m_pointCache[i].getDistance(); 69 } 70 } 71 #endif //KEEP_DEEPEST_POINT 72 73 b3Scalar res0(b3Scalar(0.)),res1(b3Scalar(0.)),res2(b3Scalar(0.)),res3(b3Scalar(0.)); 74 75 if (gContactCalcArea3Points) 76 { 77 if (maxPenetrationIndex != 0) 78 { 79 b3Vector3 a0 = pt.m_localPointA-m_pointCache[1].m_localPointA; 80 b3Vector3 b0 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA; 81 b3Vector3 cross = a0.cross(b0); 82 res0 = cross.length2(); 83 } 84 if (maxPenetrationIndex != 1) 85 { 86 b3Vector3 a1 = pt.m_localPointA-m_pointCache[0].m_localPointA; 87 b3Vector3 b1 = m_pointCache[3].m_localPointA-m_pointCache[2].m_localPointA; 88 b3Vector3 cross = a1.cross(b1); 89 res1 = cross.length2(); 90 } 91 92 if (maxPenetrationIndex != 2) 93 { 94 b3Vector3 a2 = pt.m_localPointA-m_pointCache[0].m_localPointA; 95 b3Vector3 b2 = m_pointCache[3].m_localPointA-m_pointCache[1].m_localPointA; 96 b3Vector3 cross = a2.cross(b2); 97 res2 = cross.length2(); 98 } 99 100 if (maxPenetrationIndex != 3) 101 { 102 b3Vector3 a3 = pt.m_localPointA-m_pointCache[0].m_localPointA; 103 b3Vector3 b3 = m_pointCache[2].m_localPointA-m_pointCache[1].m_localPointA; 104 b3Vector3 cross = a3.cross(b3); 105 res3 = cross.length2(); 106 } 107 } 108 else 109 { 110 if(maxPenetrationIndex != 0) { 111 res0 = calcArea4Points(pt.m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA); 112 } 113 114 if(maxPenetrationIndex != 1) { 115 res1 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA); 116 } 117 118 if(maxPenetrationIndex != 2) { 119 res2 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[3].m_localPointA); 120 } 121 122 if(maxPenetrationIndex != 3) { 123 res3 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA); 124 } 125 } 126 b3Vector4 maxvec(res0,res1,res2,res3); 127 int biggestarea = maxvec.closestAxis4(); 128 return biggestarea; 129 130 } 131 132 133 int b3ContactCache::getCacheEntry(const b3Vector3& newPoint) const 134 { 135 b3Scalar shortestDist = getContactBreakingThreshold() * getContactBreakingThreshold(); 136 int size = getNumContacts(); 137 int nearestPoint = -1; 138 for( int i = 0; i < size; i++ ) 139 { 140 const b3Vector3 &mp = m_pointCache[i]; 141 142 b3Vector3 diffA = mp.m_localPointA- newPoint.m_localPointA; 143 const b3Scalar distToManiPoint = diffA.dot(diffA); 144 if( distToManiPoint < shortestDist ) 145 { 146 shortestDist = distToManiPoint; 147 nearestPoint = i; 148 } 149 } 150 return nearestPoint; 151 } 152 153 int b3ContactCache::addManifoldPoint(const b3Vector3& newPoint) 154 { 155 b3Assert(validContactDistance(newPoint)); 156 157 int insertIndex = getNumContacts(); 158 if (insertIndex == MANIFOLD_CACHE_SIZE) 159 { 160 #if MANIFOLD_CACHE_SIZE >= 4 161 //sort cache so best points come first, based on area 162 insertIndex = sortCachedPoints(newPoint); 163 #else 164 insertIndex = 0; 165 #endif 166 clearUserCache(m_pointCache[insertIndex]); 167 168 } else 169 { 170 m_cachedPoints++; 171 172 173 } 174 if (insertIndex<0) 175 insertIndex=0; 176 177 //b3Assert(m_pointCache[insertIndex].m_userPersistentData==0); 178 m_pointCache[insertIndex] = newPoint; 179 return insertIndex; 180 } 181 182 #endif 183 184 bool b3ContactCache::validContactDistance(const b3Vector3& pt) 185 { 186 return pt.w <= gContactBreakingThreshold; 187 } 188 189 void b3ContactCache::removeContactPoint(struct b3Contact4Data& newContactCache,int i) 190 { 191 int numContacts = b3Contact4Data_getNumPoints(&newContactCache); 192 if (i!=(numContacts-1)) 193 { 194 b3Swap(newContactCache.m_localPosA[i],newContactCache.m_localPosA[numContacts-1]); 195 b3Swap(newContactCache.m_localPosB[i],newContactCache.m_localPosB[numContacts-1]); 196 b3Swap(newContactCache.m_worldPosB[i],newContactCache.m_worldPosB[numContacts-1]); 197 } 198 b3Contact4Data_setNumPoints(&newContactCache,numContacts-1); 199 200 } 201 202 203 void b3ContactCache::refreshContactPoints(const b3Transform& trA,const b3Transform& trB, struct b3Contact4Data& contacts) 204 { 205 206 int numContacts = b3Contact4Data_getNumPoints(&contacts); 207 208 209 int i; 210 /// first refresh worldspace positions and distance 211 for (i=numContacts-1;i>=0;i--) 212 { 213 b3Vector3 worldPosA = trA( contacts.m_localPosA[i]); 214 b3Vector3 worldPosB = trB( contacts.m_localPosB[i]); 215 contacts.m_worldPosB[i] = worldPosB; 216 float distance = (worldPosA - worldPosB).dot(contacts.m_worldNormalOnB); 217 contacts.m_worldPosB[i].w = distance; 218 } 219 220 /// then 221 b3Scalar distance2d; 222 b3Vector3 projectedDifference,projectedPoint; 223 for (i=numContacts-1;i>=0;i--) 224 { 225 b3Vector3 worldPosA = trA( contacts.m_localPosA[i]); 226 b3Vector3 worldPosB = trB( contacts.m_localPosB[i]); 227 b3Vector3&pt = contacts.m_worldPosB[i]; 228 //contact becomes invalid when signed distance exceeds margin (projected on contactnormal direction) 229 if (!validContactDistance(pt)) 230 { 231 removeContactPoint(contacts,i); 232 } else 233 { 234 //contact also becomes invalid when relative movement orthogonal to normal exceeds margin 235 projectedPoint = worldPosA - contacts.m_worldNormalOnB * contacts.m_worldPosB[i].w; 236 projectedDifference = contacts.m_worldPosB[i] - projectedPoint; 237 distance2d = projectedDifference.dot(projectedDifference); 238 if (distance2d > gContactBreakingThreshold*gContactBreakingThreshold ) 239 { 240 removeContactPoint(contacts,i); 241 } else 242 { 243 ////contact point processed callback 244 //if (gContactProcessedCallback) 245 // (*gContactProcessedCallback)(manifoldPoint,(void*)m_body0,(void*)m_body1); 246 } 247 } 248 } 249 250 251 } 252 253 #endif 254