b2Distance.h
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00001 
00002 /*
00003 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
00004 *
00005 * This software is provided 'as-is', without any express or implied
00006 * warranty.  In no event will the authors be held liable for any damages
00007 * arising from the use of this software.
00008 * Permission is granted to anyone to use this software for any purpose,
00009 * including commercial applications, and to alter it and redistribute it
00010 * freely, subject to the following restrictions:
00011 * 1. The origin of this software must not be misrepresented; you must not
00012 * claim that you wrote the original software. If you use this software
00013 * in a product, an acknowledgment in the product documentation would be
00014 * appreciated but is not required.
00015 * 2. Altered source versions must be plainly marked as such, and must not be
00016 * misrepresented as being the original software.
00017 * 3. This notice may not be removed or altered from any source distribution.
00018 */
00019 
00020 #ifndef B2_DISTANCE_H
00021 #define B2_DISTANCE_H
00022 
00023 #include <Box2D/Common/b2Math.h>
00024 
00025 class b2Shape;
00026 
00029 struct b2DistanceProxy
00030 {
00031         b2DistanceProxy() : m_vertices(NULL), m_count(0), m_radius(0.0f) {}
00032 
00035         void Set(const b2Shape* shape, int32 index);
00036 
00038         int32 GetSupport(const b2Vec2& d) const;
00039 
00041         const b2Vec2& GetSupportVertex(const b2Vec2& d) const;
00042 
00044         int32 GetVertexCount() const;
00045 
00047         const b2Vec2& GetVertex(int32 index) const;
00048 
00049         b2Vec2 m_buffer[2];
00050         const b2Vec2* m_vertices;
00051         int32 m_count;
00052         float32 m_radius;
00053 };
00054 
00057 struct b2SimplexCache
00058 {
00059         float32 metric;         
00060         uint16 count;
00061         uint8 indexA[3];        
00062         uint8 indexB[3];        
00063 };
00064 
00068 struct b2DistanceInput
00069 {
00070         b2DistanceProxy proxyA;
00071         b2DistanceProxy proxyB;
00072         b2Transform transformA;
00073         b2Transform transformB;
00074         bool useRadii;
00075 };
00076 
00078 struct b2DistanceOutput
00079 {
00080         b2Vec2 pointA;          
00081         b2Vec2 pointB;          
00082         float32 distance;
00083         int32 iterations;       
00084 };
00085 
00089 void b2Distance(b2DistanceOutput* output,
00090                                 b2SimplexCache* cache, 
00091                                 const b2DistanceInput* input);
00092 
00093 
00095 
00096 inline int32 b2DistanceProxy::GetVertexCount() const
00097 {
00098         return m_count;
00099 }
00100 
00101 inline const b2Vec2& b2DistanceProxy::GetVertex(int32 index) const
00102 {
00103         b2Assert(0 <= index && index < m_count);
00104         return m_vertices[index];
00105 }
00106 
00107 inline int32 b2DistanceProxy::GetSupport(const b2Vec2& d) const
00108 {
00109         int32 bestIndex = 0;
00110         float32 bestValue = b2Dot(m_vertices[0], d);
00111         for (int32 i = 1; i < m_count; ++i)
00112         {
00113                 float32 value = b2Dot(m_vertices[i], d);
00114                 if (value > bestValue)
00115                 {
00116                         bestIndex = i;
00117                         bestValue = value;
00118                 }
00119         }
00120 
00121         return bestIndex;
00122 }
00123 
00124 inline const b2Vec2& b2DistanceProxy::GetSupportVertex(const b2Vec2& d) const
00125 {
00126         int32 bestIndex = 0;
00127         float32 bestValue = b2Dot(m_vertices[0], d);
00128         for (int32 i = 1; i < m_count; ++i)
00129         {
00130                 float32 value = b2Dot(m_vertices[i], d);
00131                 if (value > bestValue)
00132                 {
00133                         bestIndex = i;
00134                         bestValue = value;
00135                 }
00136         }
00137 
00138         return m_vertices[bestIndex];
00139 }
00140 
00141 #endif


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autogenerated on Thu Jun 6 2019 22:08:34