Bullet Collision Detection & Physics Library
btConvexHullComputer.h
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1 /*
2 Copyright (c) 2011 Ole Kniemeyer, MAXON, www.maxon.net
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 #ifndef BT_CONVEX_HULL_COMPUTER_H
16 #define BT_CONVEX_HULL_COMPUTER_H
17 
18 #include "btVector3.h"
19 #include "btAlignedObjectArray.h"
20 
25 {
26 private:
27  btScalar compute(const void* coords, bool doubleCoords, int stride, int count, btScalar shrink, btScalar shrinkClamp);
28 
29 public:
30  class Edge
31  {
32  private:
33  int next;
34  int reverse;
36 
37  friend class btConvexHullComputer;
38 
39  public:
40  int getSourceVertex() const
41  {
42  return (this + reverse)->targetVertex;
43  }
44 
45  int getTargetVertex() const
46  {
47  return targetVertex;
48  }
49 
50  const Edge* getNextEdgeOfVertex() const // clockwise list of all edges of a vertex
51  {
52  return this + next;
53  }
54 
55  const Edge* getNextEdgeOfFace() const // counter-clockwise list of all edges of a face
56  {
57  return (this + reverse)->getNextEdgeOfVertex();
58  }
59 
60  const Edge* getReverseEdge() const
61  {
62  return this + reverse;
63  }
64  };
65 
66  // Vertices of the output hull
68 
69  // Edges of the output hull
71 
72  // Faces of the convex hull. Each entry is an index into the "edges" array pointing to an edge of the face. Faces are planar n-gons
74 
75  /*
76  Compute convex hull of "count" vertices stored in "coords". "stride" is the difference in bytes
77  between the addresses of consecutive vertices. If "shrink" is positive, the convex hull is shrunken
78  by that amount (each face is moved by "shrink" length units towards the center along its normal).
79  If "shrinkClamp" is positive, "shrink" is clamped to not exceed "shrinkClamp * innerRadius", where "innerRadius"
80  is the minimum distance of a face to the center of the convex hull.
81 
82  The returned value is the amount by which the hull has been shrunken. If it is negative, the amount was so large
83  that the resulting convex hull is empty.
84 
85  The output convex hull can be found in the member variables "vertices", "edges", "faces".
86  */
87  btScalar compute(const float* coords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
88  {
89  return compute(coords, false, stride, count, shrink, shrinkClamp);
90  }
91 
92  // same as above, but double precision
93  btScalar compute(const double* coords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
94  {
95  return compute(coords, true, stride, count, shrink, shrinkClamp);
96  }
97 };
98 
99 #endif //BT_CONVEX_HULL_COMPUTER_H
btConvexHullComputer::Edge::getNextEdgeOfFace
const Edge * getNextEdgeOfFace() const
Definition: btConvexHullComputer.h:55
btConvexHullComputer::vertices
btAlignedObjectArray< btVector3 > vertices
Definition: btConvexHullComputer.h:67
btConvexHullComputer::Edge::reverse
int reverse
Definition: btConvexHullComputer.h:34
btConvexHullComputer::compute
btScalar compute(const double *coords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
Definition: btConvexHullComputer.h:93
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:294
btConvexHullComputer::Edge::getTargetVertex
int getTargetVertex() const
Definition: btConvexHullComputer.h:45
btConvexHullComputer::Edge::getNextEdgeOfVertex
const Edge * getNextEdgeOfVertex() const
Definition: btConvexHullComputer.h:50
btConvexHullComputer::Edge::getSourceVertex
int getSourceVertex() const
Definition: btConvexHullComputer.h:40
btConvexHullComputer::faces
btAlignedObjectArray< int > faces
Definition: btConvexHullComputer.h:73
btConvexHullComputer::Edge::targetVertex
int targetVertex
Definition: btConvexHullComputer.h:35
btVector3.h
btConvexHullComputer::edges
btAlignedObjectArray< Edge > edges
Definition: btConvexHullComputer.h:70
btConvexHullComputer
Convex hull implementation based on Preparata and Hong See http://code.google.com/p/bullet/issues/det...
Definition: btConvexHullComputer.h:24
btConvexHullComputer::Edge::next
int next
Definition: btConvexHullComputer.h:33
btAlignedObjectArray< btVector3 >
btConvexHullComputer::Edge
Definition: btConvexHullComputer.h:30
btAlignedObjectArray.h
btConvexHullComputer::compute
btScalar compute(const void *coords, bool doubleCoords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
Definition: btConvexHullComputer.cpp:2653
btConvexHullComputer::Edge::getReverseEdge
const Edge * getReverseEdge() const
Definition: btConvexHullComputer.h:60
btConvexHullComputer::compute
btScalar compute(const float *coords, int stride, int count, btScalar shrink, btScalar shrinkClamp)
Definition: btConvexHullComputer.h:87