1 /* 2 Bullet Continuous Collision Detection and Physics Library 3 Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/ 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 ///btSparseSdf implementation by Nathanael Presson 16 17 #ifndef BT_SPARSE_SDF_H 18 #define BT_SPARSE_SDF_H 19 20 #include "BulletCollision/CollisionDispatch/btCollisionObject.h" 21 #include "BulletCollision/NarrowPhaseCollision/btGjkEpa2.h" 22 23 // Modified Paul Hsieh hash 24 template <const int DWORDLEN> 25 unsigned int HsiehHash(const void* pdata) 26 { 27 const unsigned short* data=(const unsigned short*)pdata; 28 unsigned hash=DWORDLEN<<2,tmp; 29 for(int i=0;i<DWORDLEN;++i) 30 { 31 hash += data[0]; 32 tmp = (data[1]<<11)^hash; 33 hash = (hash<<16)^tmp; 34 data += 2; 35 hash += hash>>11; 36 } 37 hash^=hash<<3;hash+=hash>>5; 38 hash^=hash<<4;hash+=hash>>17; 39 hash^=hash<<25;hash+=hash>>6; 40 return(hash); 41 } 42 43 template <const int CELLSIZE> 44 struct btSparseSdf 45 { 46 // 47 // Inner types 48 // 49 struct IntFrac 50 { 51 int b; 52 int i; 53 btScalar f; 54 }; 55 struct Cell 56 { 57 btScalar d[CELLSIZE+1][CELLSIZE+1][CELLSIZE+1]; 58 int c[3]; 59 int puid; 60 unsigned hash; 61 const btCollisionShape* pclient; 62 Cell* next; 63 }; 64 // 65 // Fields 66 // 67 68 btAlignedObjectArray<Cell*> cells; 69 btScalar voxelsz; 70 int puid; 71 int ncells; 72 int m_clampCells; 73 int nprobes; 74 int nqueries; 75 76 // 77 // Methods 78 // 79 80 // 81 void Initialize(int hashsize=2383, int clampCells = 256*1024) 82 { 83 //avoid a crash due to running out of memory, so clamp the maximum number of cells allocated 84 //if this limit is reached, the SDF is reset (at the cost of some performance during the reset) 85 m_clampCells = clampCells; 86 cells.resize(hashsize,0); 87 Reset(); 88 } 89 // 90 void Reset() 91 { 92 for(int i=0,ni=cells.size();i<ni;++i) 93 { 94 Cell* pc=cells[i]; 95 cells[i]=0; 96 while(pc) 97 { 98 Cell* pn=pc->next; 99 delete pc; 100 pc=pn; 101 } 102 } 103 voxelsz =0.25; 104 puid =0; 105 ncells =0; 106 nprobes =1; 107 nqueries =1; 108 } 109 // 110 void GarbageCollect(int lifetime=256) 111 { 112 const int life=puid-lifetime; 113 for(int i=0;i<cells.size();++i) 114 { 115 Cell*& root=cells[i]; 116 Cell* pp=0; 117 Cell* pc=root; 118 while(pc) 119 { 120 Cell* pn=pc->next; 121 if(pc->puid<life) 122 { 123 if(pp) pp->next=pn; else root=pn; 124 delete pc;pc=pp;--ncells; 125 } 126 pp=pc;pc=pn; 127 } 128 } 129 //printf("GC[%d]: %d cells, PpQ: %f\r\n",puid,ncells,nprobes/(btScalar)nqueries); 130 nqueries=1; 131 nprobes=1; 132 ++puid; ///@todo: Reset puid's when int range limit is reached */ 133 /* else setup a priority list... */ 134 } 135 // 136 int RemoveReferences(btCollisionShape* pcs) 137 { 138 int refcount=0; 139 for(int i=0;i<cells.size();++i) 140 { 141 Cell*& root=cells[i]; 142 Cell* pp=0; 143 Cell* pc=root; 144 while(pc) 145 { 146 Cell* pn=pc->next; 147 if(pc->pclient==pcs) 148 { 149 if(pp) pp->next=pn; else root=pn; 150 delete pc;pc=pp;++refcount; 151 } 152 pp=pc;pc=pn; 153 } 154 } 155 return(refcount); 156 } 157 // 158 btScalar Evaluate( const btVector3& x, 159 const btCollisionShape* shape, 160 btVector3& normal, 161 btScalar margin) 162 { 163 /* Lookup cell */ 164 const btVector3 scx=x/voxelsz; 165 const IntFrac ix=Decompose(scx.x()); 166 const IntFrac iy=Decompose(scx.y()); 167 const IntFrac iz=Decompose(scx.z()); 168 const unsigned h=Hash(ix.b,iy.b,iz.b,shape); 169 Cell*& root=cells[static_cast<int>(h%cells.size())]; 170 Cell* c=root; 171 ++nqueries; 172 while(c) 173 { 174 ++nprobes; 175 if( (c->hash==h) && 176 (c->c[0]==ix.b) && 177 (c->c[1]==iy.b) && 178 (c->c[2]==iz.b) && 179 (c->pclient==shape)) 180 { break; } 181 else 182 { c=c->next; } 183 } 184 if(!c) 185 { 186 ++nprobes; 187 ++ncells; 188 int sz = sizeof(Cell); 189 if (ncells>m_clampCells) 190 { 191 static int numResets=0; 192 numResets++; 193 // printf("numResets=%d\n",numResets); 194 Reset(); 195 } 196 197 c=new Cell(); 198 c->next=root;root=c; 199 c->pclient=shape; 200 c->hash=h; 201 c->c[0]=ix.b;c->c[1]=iy.b;c->c[2]=iz.b; 202 BuildCell(*c); 203 } 204 c->puid=puid; 205 /* Extract infos */ 206 const int o[]={ ix.i,iy.i,iz.i}; 207 const btScalar d[]={ c->d[o[0]+0][o[1]+0][o[2]+0], 208 c->d[o[0]+1][o[1]+0][o[2]+0], 209 c->d[o[0]+1][o[1]+1][o[2]+0], 210 c->d[o[0]+0][o[1]+1][o[2]+0], 211 c->d[o[0]+0][o[1]+0][o[2]+1], 212 c->d[o[0]+1][o[1]+0][o[2]+1], 213 c->d[o[0]+1][o[1]+1][o[2]+1], 214 c->d[o[0]+0][o[1]+1][o[2]+1]}; 215 /* Normal */ 216 #if 1 217 const btScalar gx[]={ d[1]-d[0],d[2]-d[3], 218 d[5]-d[4],d[6]-d[7]}; 219 const btScalar gy[]={ d[3]-d[0],d[2]-d[1], 220 d[7]-d[4],d[6]-d[5]}; 221 const btScalar gz[]={ d[4]-d[0],d[5]-d[1], 222 d[7]-d[3],d[6]-d[2]}; 223 normal.setX(Lerp( Lerp(gx[0],gx[1],iy.f), 224 Lerp(gx[2],gx[3],iy.f),iz.f)); 225 normal.setY(Lerp( Lerp(gy[0],gy[1],ix.f), 226 Lerp(gy[2],gy[3],ix.f),iz.f)); 227 normal.setZ(Lerp( Lerp(gz[0],gz[1],ix.f), 228 Lerp(gz[2],gz[3],ix.f),iy.f)); 229 normal = normal.normalized(); 230 #else 231 normal = btVector3(d[1]-d[0],d[3]-d[0],d[4]-d[0]).normalized(); 232 #endif 233 /* Distance */ 234 const btScalar d0=Lerp(Lerp(d[0],d[1],ix.f), 235 Lerp(d[3],d[2],ix.f),iy.f); 236 const btScalar d1=Lerp(Lerp(d[4],d[5],ix.f), 237 Lerp(d[7],d[6],ix.f),iy.f); 238 return(Lerp(d0,d1,iz.f)-margin); 239 } 240 // 241 void BuildCell(Cell& c) 242 { 243 const btVector3 org=btVector3( (btScalar)c.c[0], 244 (btScalar)c.c[1], 245 (btScalar)c.c[2]) * 246 CELLSIZE*voxelsz; 247 for(int k=0;k<=CELLSIZE;++k) 248 { 249 const btScalar z=voxelsz*k+org.z(); 250 for(int j=0;j<=CELLSIZE;++j) 251 { 252 const btScalar y=voxelsz*j+org.y(); 253 for(int i=0;i<=CELLSIZE;++i) 254 { 255 const btScalar x=voxelsz*i+org.x(); 256 c.d[i][j][k]=DistanceToShape( btVector3(x,y,z), 257 c.pclient); 258 } 259 } 260 } 261 } 262 // 263 static inline btScalar DistanceToShape(const btVector3& x, 264 const btCollisionShape* shape) 265 { 266 btTransform unit; 267 unit.setIdentity(); 268 if(shape->isConvex()) 269 { 270 btGjkEpaSolver2::sResults res; 271 const btConvexShape* csh=static_cast<const btConvexShape*>(shape); 272 return(btGjkEpaSolver2::SignedDistance(x,0,csh,unit,res)); 273 } 274 return(0); 275 } 276 // 277 static inline IntFrac Decompose(btScalar x) 278 { 279 /* That one need a lot of improvements... */ 280 /* Remove test, faster floor... */ 281 IntFrac r; 282 x/=CELLSIZE; 283 const int o=x<0?(int)(-x+1):0; 284 x+=o;r.b=(int)x; 285 const btScalar k=(x-r.b)*CELLSIZE; 286 r.i=(int)k;r.f=k-r.i;r.b-=o; 287 return(r); 288 } 289 // 290 static inline btScalar Lerp(btScalar a,btScalar b,btScalar t) 291 { 292 return(a+(b-a)*t); 293 } 294 295 296 297 // 298 static inline unsigned int Hash(int x,int y,int z,const btCollisionShape* shape) 299 { 300 struct btS 301 { 302 int x,y,z; 303 void* p; 304 }; 305 306 btS myset; 307 308 myset.x=x;myset.y=y;myset.z=z;myset.p=(void*)shape; 309 const void* ptr = &myset; 310 311 unsigned int result = HsiehHash<sizeof(btS)/4> (ptr); 312 313 314 return result; 315 } 316 }; 317 318 319 #endif //BT_SPARSE_SDF_H 320
