00001 /* 00002 Copyright (c) 2011 Ole Kniemeyer, MAXON, www.maxon.net 00003 00004 This software is provided 'as-is', without any express or implied warranty. 00005 In no event will the authors be held liable for any damages arising from the use of this software. 00006 Permission is granted to anyone to use this software for any purpose, 00007 including commercial applications, and to alter it and redistribute it freely, 00008 subject to the following restrictions: 00009 00010 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. 00011 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 00012 3. This notice may not be removed or altered from any source distribution. 00013 */ 00014 00015 #ifndef BT_CONVEX_HULL_COMPUTER_H 00016 #define BT_CONVEX_HULL_COMPUTER_H 00017 00018 #include "btAlignedObjectArray.h" 00019 #include "btVector3.h" 00020 00024 class btConvexHullComputer { 00025 private: 00026 btScalar compute(const void* coords, bool doubleCoords, int32_t stride, int32_t count, btScalar shrink, btScalar shrinkClamp); 00027 00028 public: 00029 class Edge { 00030 private: 00031 int32_t next; 00032 int32_t reverse; 00033 int32_t targetVertex; 00034 00035 friend class btConvexHullComputer; 00036 00037 public: 00038 int32_t getSourceVertex() const 00039 { 00040 return (this + reverse)->targetVertex; 00041 } 00042 00043 int32_t getTargetVertex() const 00044 { 00045 return targetVertex; 00046 } 00047 00048 const Edge* getNextEdgeOfVertex() const // clockwise list of all edges of a vertex 00049 { 00050 return this + next; 00051 } 00052 00053 const Edge* getNextEdgeOfFace() const // counter-clockwise list of all edges of a face 00054 { 00055 return (this + reverse)->getNextEdgeOfVertex(); 00056 } 00057 00058 const Edge* getReverseEdge() const 00059 { 00060 return this + reverse; 00061 } 00062 }; 00063 00064 // Vertices of the output hull 00065 btAlignedObjectArray<btVector3> vertices; 00066 00067 // Edges of the output hull 00068 btAlignedObjectArray<Edge> edges; 00069 00070 // 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 00071 btAlignedObjectArray<int32_t> faces; 00072 00073 /* 00074 Compute convex hull of "count" vertices stored in "coords". "stride" is the difference in bytes 00075 between the addresses of consecutive vertices. If "shrink" is positive, the convex hull is shrunken 00076 by that amount (each face is moved by "shrink" length units towards the center along its normal). 00077 If "shrinkClamp" is positive, "shrink" is clamped to not exceed "shrinkClamp * innerRadius", where "innerRadius" 00078 is the minimum distance of a face to the center of the convex hull. 00079 00080 The returned value is the amount by which the hull has been shrunken. If it is negative, the amount was so large 00081 that the resulting convex hull is empty. 00082 00083 The output convex hull can be found in the member variables "vertices", "edges", "faces". 00084 */ 00085 btScalar compute(const float* coords, int32_t stride, int32_t count, btScalar shrink, btScalar shrinkClamp) 00086 { 00087 return compute(coords, false, stride, count, shrink, shrinkClamp); 00088 } 00089 00090 // same as above, but double precision 00091 btScalar compute(const double* coords, int32_t stride, int32_t count, btScalar shrink, btScalar shrinkClamp) 00092 { 00093 return compute(coords, true, stride, count, shrink, shrinkClamp); 00094 } 00095 }; 00096 00097 #endif //BT_CONVEX_HULL_COMPUTER_H