dali-physics/third-party/bullet3/src/LinearMath/btGeometryUtil.cpp

   1 /*
   2 Copyright (c) 2003-2006 Gino van den Bergen / Erwin Coumans  https://bulletphysics.org
   3
   4 This software is provided 'as-is', without any express or implied warranty.
   5 In no event will the authors be held liable for any damages arising from the use of this software.
   6 Permission is granted to anyone to use this software for any purpose,
   7 including commercial applications, and to alter it and redistribute it freely,
   8 subject to the following restrictions:
   9
  10 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.
  11 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
  12 3. This notice may not be removed or altered from any source distribution.
  13 */
  14
  15 #include "btGeometryUtil.h"
  16
  17 /*
  18   Make sure this dummy function never changes so that it
  19   can be used by probes that are checking whether the
  20   library is actually installed.
  21 */
  22 extern "C"
  23 {
  24         void btBulletMathProbe();
  25
  26         void btBulletMathProbe() {}
  27 }
  28
  29 bool btGeometryUtil::isPointInsidePlanes(const btAlignedObjectArray<btVector3>& planeEquations, const btVector3& point, btScalar margin)
  30 {
  31         int numbrushes = planeEquations.size();
  32         for (int i = 0; i < numbrushes; i++)
  33         {
  34                 const btVector3& N1 = planeEquations[i];
  35                 btScalar dist = btScalar(N1.dot(point)) + btScalar(N1[3]) - margin;
  36                 if (dist > btScalar(0.))
  37                 {
  38                         return false;
  39                 }
  40         }
  41         return true;
  42 }
  43
  44 bool btGeometryUtil::areVerticesBehindPlane(const btVector3& planeNormal, const btAlignedObjectArray<btVector3>& vertices, btScalar margin)
  45 {
  46         int numvertices = vertices.size();
  47         for (int i = 0; i < numvertices; i++)
  48         {
  49                 const btVector3& N1 = vertices[i];
  50                 btScalar dist = btScalar(planeNormal.dot(N1)) + btScalar(planeNormal[3]) - margin;
  51                 if (dist > btScalar(0.))
  52                 {
  53                         return false;
  54                 }
  55         }
  56         return true;
  57 }
  58
  59 bool notExist(const btVector3& planeEquation, const btAlignedObjectArray<btVector3>& planeEquations);
  60
  61 bool notExist(const btVector3& planeEquation, const btAlignedObjectArray<btVector3>& planeEquations)
  62 {
  63         int numbrushes = planeEquations.size();
  64         for (int i = 0; i < numbrushes; i++)
  65         {
  66                 const btVector3& N1 = planeEquations[i];
  67                 if (planeEquation.dot(N1) > btScalar(0.999))
  68                 {
  69                         return false;
  70                 }
  71         }
  72         return true;
  73 }
  74
  75 void btGeometryUtil::getPlaneEquationsFromVertices(btAlignedObjectArray<btVector3>& vertices, btAlignedObjectArray<btVector3>& planeEquationsOut)
  76 {
  77         const int numvertices = vertices.size();
  78         // brute force:
  79         for (int i = 0; i < numvertices; i++)
  80         {
  81                 const btVector3& N1 = vertices[i];
  82
  83                 for (int j = i + 1; j < numvertices; j++)
  84                 {
  85                         const btVector3& N2 = vertices[j];
  86
  87                         for (int k = j + 1; k < numvertices; k++)
  88                         {
  89                                 const btVector3& N3 = vertices[k];
  90
  91                                 btVector3 planeEquation, edge0, edge1;
  92                                 edge0 = N2 - N1;
  93                                 edge1 = N3 - N1;
  94                                 btScalar normalSign = btScalar(1.);
  95                                 for (int ww = 0; ww < 2; ww++)
  96                                 {
  97                                         planeEquation = normalSign * edge0.cross(edge1);
  98                                         if (planeEquation.length2() > btScalar(0.0001))
  99                                         {
 100                                                 planeEquation.normalize();
 101                                                 if (notExist(planeEquation, planeEquationsOut))
 102                                                 {
 103                                                         planeEquation[3] = -planeEquation.dot(N1);
 104
 105                                                         //check if inside, and replace supportingVertexOut if needed
 106                                                         if (areVerticesBehindPlane(planeEquation, vertices, btScalar(0.01)))
 107                                                         {
 108                                                                 planeEquationsOut.push_back(planeEquation);
 109                                                         }
 110                                                 }
 111                                         }
 112                                         normalSign = btScalar(-1.);
 113                                 }
 114                         }
 115                 }
 116         }
 117 }
 118
 119 void btGeometryUtil::getVerticesFromPlaneEquations(const btAlignedObjectArray<btVector3>& planeEquations, btAlignedObjectArray<btVector3>& verticesOut)
 120 {
 121         const int numbrushes = planeEquations.size();
 122         // brute force:
 123         for (int i = 0; i < numbrushes; i++)
 124         {
 125                 const btVector3& N1 = planeEquations[i];
 126
 127                 for (int j = i + 1; j < numbrushes; j++)
 128                 {
 129                         const btVector3& N2 = planeEquations[j];
 130
 131                         for (int k = j + 1; k < numbrushes; k++)
 132                         {
 133                                 const btVector3& N3 = planeEquations[k];
 134
 135                                 btVector3 n2n3;
 136                                 n2n3 = N2.cross(N3);
 137                                 btVector3 n3n1;
 138                                 n3n1 = N3.cross(N1);
 139                                 btVector3 n1n2;
 140                                 n1n2 = N1.cross(N2);
 141
 142                                 if ((n2n3.length2() > btScalar(0.0001)) &&
 143                                         (n3n1.length2() > btScalar(0.0001)) &&
 144                                         (n1n2.length2() > btScalar(0.0001)))
 145                                 {
 146                                         //point P out of 3 plane equations:
 147
 148                                         //      d1 ( N2 * N3 ) + d2 ( N3 * N1 ) + d3 ( N1 * N2 )
 149                                         //P =  -------------------------------------------------------------------------
 150                                         //   N1 . ( N2 * N3 )
 151
 152                                         btScalar quotient = (N1.dot(n2n3));
 153                                         if (btFabs(quotient) > btScalar(0.000001))
 154                                         {
 155                                                 quotient = btScalar(-1.) / quotient;
 156                                                 n2n3 *= N1[3];
 157                                                 n3n1 *= N2[3];
 158                                                 n1n2 *= N3[3];
 159                                                 btVector3 potentialVertex = n2n3;
 160                                                 potentialVertex += n3n1;
 161                                                 potentialVertex += n1n2;
 162                                                 potentialVertex *= quotient;
 163
 164                                                 //check if inside, and replace supportingVertexOut if needed
 165                                                 if (isPointInsidePlanes(planeEquations, potentialVertex, btScalar(0.01)))
 166                                                 {
 167                                                         verticesOut.push_back(potentialVertex);
 168                                                 }
 169                                         }
 170                                 }
 171                         }
 172                 }
 173         }
 174 }