Bullet Collision Detection & Physics Library
btConvexHullShape.cpp
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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"
22 
25 #include "btConvexPolyhedron.h"
27 
29 {
31  m_unscaledPoints.resize(numPoints);
32 
33  unsigned char* pointsAddress = (unsigned char*)points;
34 
35  for (int i=0;i<numPoints;i++)
36  {
37  btScalar* point = (btScalar*)pointsAddress;
38  m_unscaledPoints[i] = btVector3(point[0], point[1], point[2]);
39  pointsAddress += stride;
40  }
41 
43 
44 }
45 
46 
47 
49 {
50  m_localScaling = scaling;
52 }
53 
54 void btConvexHullShape::addPoint(const btVector3& point, bool recalculateLocalAabb)
55 {
57  if (recalculateLocalAabb)
59 
60 }
61 
63 {
64  btVector3 supVec(btScalar(0.),btScalar(0.),btScalar(0.));
65  btScalar maxDot = btScalar(-BT_LARGE_FLOAT);
66 
67  // Here we take advantage of dot(a, b*c) = dot(a*b, c). Note: This is true mathematically, but not numerically.
68  if( 0 < m_unscaledPoints.size() )
69  {
70  btVector3 scaled = vec * m_localScaling;
71  int index = (int) scaled.maxDot( &m_unscaledPoints[0], m_unscaledPoints.size(), maxDot); // FIXME: may violate encapsulation of m_unscaledPoints
72  return m_unscaledPoints[index] * m_localScaling;
73  }
74 
75  return supVec;
76 }
77 
78 void btConvexHullShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const
79 {
80  btScalar newDot;
81  //use 'w' component of supportVerticesOut?
82  {
83  for (int i=0;i<numVectors;i++)
84  {
85  supportVerticesOut[i][3] = btScalar(-BT_LARGE_FLOAT);
86  }
87  }
88 
89  for (int j=0;j<numVectors;j++)
90  {
91  btVector3 vec = vectors[j] * m_localScaling; // dot(a*b,c) = dot(a,b*c)
92  if( 0 < m_unscaledPoints.size() )
93  {
94  int i = (int) vec.maxDot( &m_unscaledPoints[0], m_unscaledPoints.size(), newDot);
95  supportVerticesOut[j] = getScaledPoint(i);
96  supportVerticesOut[j][3] = newDot;
97  }
98  else
99  supportVerticesOut[j][3] = -BT_LARGE_FLOAT;
100  }
101 
102 
103 
104 }
105 
106 
107 
109 {
111 
112  if ( getMargin()!=btScalar(0.) )
113  {
114  btVector3 vecnorm = vec;
115  if (vecnorm .length2() < (SIMD_EPSILON*SIMD_EPSILON))
116  {
117  vecnorm.setValue(btScalar(-1.),btScalar(-1.),btScalar(-1.));
118  }
119  vecnorm.normalize();
120  supVertex+= getMargin() * vecnorm;
121  }
122  return supVertex;
123 }
124 
125 
127 {
129  conv.compute(&m_unscaledPoints[0].getX(), sizeof(btVector3),m_unscaledPoints.size(),0.f,0.f);
130  int numVerts = conv.vertices.size();
132  for (int i=0;i<numVerts;i++)
133  {
135  }
136 }
137 
138 
139 
140 //currently just for debugging (drawing), perhaps future support for algebraic continuous collision detection
141 //Please note that you can debug-draw btConvexHullShape with the Raytracer Demo
143 {
144  return m_unscaledPoints.size();
145 }
146 
148 {
149  return m_unscaledPoints.size();
150 }
151 
153 {
154 
155  int index0 = i%m_unscaledPoints.size();
156  int index1 = (i+1)%m_unscaledPoints.size();
157  pa = getScaledPoint(index0);
158  pb = getScaledPoint(index1);
159 }
160 
162 {
163  vtx = getScaledPoint(i);
164 }
165 
167 {
168  return 0;
169 }
170 
172 {
173 
174  btAssert(0);
175 }
176 
177 //not yet
179 {
180  btAssert(0);
181  return false;
182 }
183 
185 const char* btConvexHullShape::serialize(void* dataBuffer, btSerializer* serializer) const
186 {
187  //int szc = sizeof(btConvexHullShapeData);
188  btConvexHullShapeData* shapeData = (btConvexHullShapeData*) dataBuffer;
190 
191  int numElem = m_unscaledPoints.size();
192  shapeData->m_numUnscaledPoints = numElem;
193 #ifdef BT_USE_DOUBLE_PRECISION
194  shapeData->m_unscaledPointsFloatPtr = 0;
195  shapeData->m_unscaledPointsDoublePtr = numElem ? (btVector3Data*)serializer->getUniquePointer((void*)&m_unscaledPoints[0]): 0;
196 #else
197  shapeData->m_unscaledPointsFloatPtr = numElem ? (btVector3Data*)serializer->getUniquePointer((void*)&m_unscaledPoints[0]): 0;
198  shapeData->m_unscaledPointsDoublePtr = 0;
199 #endif
200 
201  if (numElem)
202  {
203  int sz = sizeof(btVector3Data);
204  // int sz2 = sizeof(btVector3DoubleData);
205  // int sz3 = sizeof(btVector3FloatData);
206  btChunk* chunk = serializer->allocate(sz,numElem);
207  btVector3Data* memPtr = (btVector3Data*)chunk->m_oldPtr;
208  for (int i=0;i<numElem;i++,memPtr++)
209  {
210  m_unscaledPoints[i].serialize(*memPtr);
211  }
212  serializer->finalizeChunk(chunk,btVector3DataName,BT_ARRAY_CODE,(void*)&m_unscaledPoints[0]);
213  }
214 
215  return "btConvexHullShapeData";
216 }
217 
218 void btConvexHullShape::project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const
219 {
220 #if 1
221  minProj = FLT_MAX;
222  maxProj = -FLT_MAX;
223 
224  int numVerts = m_unscaledPoints.size();
225  for(int i=0;i<numVerts;i++)
226  {
228  btVector3 pt = trans * vtx;
229  btScalar dp = pt.dot(dir);
230  if(dp < minProj)
231  {
232  minProj = dp;
233  witnesPtMin = pt;
234  }
235  if(dp > maxProj)
236  {
237  maxProj = dp;
238  witnesPtMax=pt;
239  }
240  }
241 #else
242  btVector3 localAxis = dir*trans.getBasis();
243  witnesPtMin = trans(localGetSupportingVertex(localAxis));
244  witnesPtMax = trans(localGetSupportingVertex(-localAxis));
245 
246  minProj = witnesPtMin.dot(dir);
247  maxProj = witnesPtMax.dot(dir);
248 #endif
249 
250  if(minProj>maxProj)
251  {
252  btSwap(minProj,maxProj);
253  btSwap(witnesPtMin,witnesPtMax);
254  }
255 
256 
257 }
258 
259 
virtual bool isInside(const btVector3 &pt, btScalar tolerance) const
#define SIMD_EPSILON
Definition: btScalar.h:495
virtual int getNumEdges() const
void push_back(const T &_Val)
#define BT_LARGE_FLOAT
Definition: btScalar.h:281
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:650
virtual void getPlane(btVector3 &planeNormal, btVector3 &planeSupport, int i) const
virtual void * getUniquePointer(void *oldPtr)=0
btConvexInternalShapeData m_convexInternalShapeData
virtual void project(const btTransform &trans, const btVector3 &dir, btScalar &minProj, btScalar &maxProj, btVector3 &witnesPtMin, btVector3 &witnesPtMax) const
btVector3DoubleData * m_unscaledPointsDoublePtr
virtual void getEdge(int i, btVector3 &pa, btVector3 &pb) const
#define btAssert(x)
Definition: btScalar.h:114
btAlignedObjectArray< btVector3 > m_unscaledPoints
#define btVector3Data
Definition: btVector3.h:29
Convex hull implementation based on Preparata and Hong See http://code.google.com/p/bullet/issues/det...
btVector3 & normalize()
Normalize this vector x^2 + y^2 + z^2 = 1.
Definition: btVector3.h:307
btConvexHullShape(const btScalar *points=0, int numPoints=0, int stride=sizeof(btVector3))
this constructor optionally takes in a pointer to points.
#define btVector3DataName
Definition: btVector3.h:30
long maxDot(const btVector3 *array, long array_count, btScalar &dotOut) const
returns index of maximum dot product between this and vectors in array[]
Definition: btVector3.h:1011
virtual const char * serialize(void *dataBuffer, btSerializer *serializer) const
fills the dataBuffer and returns the struct name (and 0 on failure)
do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64 ...
void btSwap(T &a, T &b)
Definition: btScalar.h:586
virtual int getNumVertices() const
virtual btScalar getMargin() const
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:235
btMatrix3x3 & getBasis()
Return the basis matrix for the rotation.
Definition: btTransform.h:112
btVector3 getScaledPoint(int i) const
btVector3FloatData * m_unscaledPointsFloatPtr
#define BT_ARRAY_CODE
Definition: btSerializer.h:126
virtual int getNumPlanes() const
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:83
int size() const
return the number of elements in the array
btAlignedObjectArray< btVector3 > vertices
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:34
The btPolyhedralConvexAabbCachingShape adds aabb caching to the btPolyhedralConvexShape.
virtual void finalizeChunk(btChunk *chunk, const char *structType, int chunkCode, void *oldPtr)=0
virtual void setLocalScaling(const btVector3 &scaling)
in case we receive negative scaling
virtual btVector3 localGetSupportingVertex(const btVector3 &vec) const
void resize(int newsize, const T &fillData=T())
virtual const char * serialize(void *dataBuffer, btSerializer *serializer) const
fills the dataBuffer and returns the struct name (and 0 on failure)
void addPoint(const btVector3 &point, bool recalculateLocalAabb=true)
btScalar compute(const void *coords, bool doubleCoords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
virtual void getVertex(int i, btVector3 &vtx) const
void * m_oldPtr
Definition: btSerializer.h:56
virtual btChunk * allocate(size_t size, int numElements)=0
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3 *vectors, btVector3 *supportVerticesOut, int numVectors) const
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:279
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const