Added support for separating axis test for polyhedral shapes
Added initial support for polyhedral contact clipping. This clipping takes a separating normal, that can be computed using either SAT or GJK/EPA. To enable clipping, use btPolyhedralConvexShape::initializePolyhedralFeatures(); (needs to be enabled for both convex shapes) No concave trimesh support for SAT/clipping yet. To enable SAT, see the toggle in btConvexConvexAlgorithm. Fixes in contact normal in btGjkPairDetector. Hopefully this doesn't cause any regression (we need unit tests!)
This commit is contained in:
erwin.coumans
@@ -145,7 +145,7 @@ public:
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virtual void getVertex(int i,btVector3& vtx) const
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{
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btVector3 halfExtents = getHalfExtentsWithoutMargin();
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btVector3 halfExtents = getHalfExtentsWithMargin();
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vtx = btVector3(
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halfExtents.x() * (1-(i&1)) - halfExtents.x() * (i&1),
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185
src/BulletCollision/CollisionShapes/btConvexPolyhedron.cpp
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185
src/BulletCollision/CollisionShapes/btConvexPolyhedron.cpp
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@@ -0,0 +1,185 @@
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/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2011 Advanced Micro Devices, Inc. http://bulletphysics.org
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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///This file was written by Erwin Coumans
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///Separating axis rest based on work from Pierre Terdiman, see
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///And contact clipping based on work from Simon Hobbs
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#include "btConvexPolyhedron.h"
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#include "LinearMath/btHashMap.h"
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btConvexPolyhedron::btConvexPolyhedron()
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{
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}
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btConvexPolyhedron::~btConvexPolyhedron()
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{
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}
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inline bool IsAlmostZero(const btVector3& v)
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{
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if(fabsf(v.x())>1e-6 || fabsf(v.y())>1e-6 || fabsf(v.z())>1e-6) return false;
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return true;
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}
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struct btInternalVertexPair
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{
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btInternalVertexPair(short int v0,short int v1)
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:m_v0(v0),
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m_v1(v1)
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{
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if (m_v1>m_v0)
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btSwap(m_v0,m_v1);
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}
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short int m_v0;
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short int m_v1;
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int getHash() const
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{
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return m_v0+(m_v1<<16);
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}
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bool equals(const btInternalVertexPair& other) const
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{
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return m_v0==other.m_v0 && m_v1==other.m_v1;
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}
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};
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struct btInternalEdge
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{
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btInternalEdge()
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:m_face0(-1),
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m_face1(-1)
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{
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}
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short int m_face0;
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short int m_face1;
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};
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//
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void btConvexPolyhedron::initialize()
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{
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btHashMap<btInternalVertexPair,btInternalEdge> edges;
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float TotalArea = 0.0f;
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m_localCenter.setValue(0, 0, 0);
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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int NbTris = numVertices;
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for(int j=0;j<NbTris;j++)
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{
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int k = (j+1)%numVertices;
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btInternalVertexPair vp(m_faces[i].m_indices[j],m_faces[i].m_indices[k]);
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btInternalEdge* edptr = edges.find(vp);
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btVector3 edge = m_vertices[vp.m_v1]-m_vertices[vp.m_v0];
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edge.normalize();
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bool found = false;
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for (int p=0;p<m_uniqueEdges.size();p++)
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{
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if (IsAlmostZero(m_uniqueEdges[p]-edge) ||
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IsAlmostZero(m_uniqueEdges[p]+edge))
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{
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found = true;
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break;
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}
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}
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if (!found)
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{
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m_uniqueEdges.push_back(edge);
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}
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if (edptr)
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{
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btAssert(edptr->m_face0>=0);
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btAssert(edptr->m_face1<0);
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edptr->m_face1 = i;
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} else
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{
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btInternalEdge ed;
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ed.m_face0 = i;
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edges.insert(vp,ed);
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}
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}
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}
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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m_faces[i].m_connectedFaces.resize(numVertices);
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for(int j=0;j<numVertices;j++)
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{
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int k = (j+1)%numVertices;
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btInternalVertexPair vp(m_faces[i].m_indices[j],m_faces[i].m_indices[k]);
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btInternalEdge* edptr = edges.find(vp);
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btAssert(edptr);
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btAssert(edptr->m_face0>=0);
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btAssert(edptr->m_face1>=0);
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int connectedFace = (edptr->m_face0==i)?edptr->m_face1:edptr->m_face0;
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m_faces[i].m_connectedFaces[j] = connectedFace;
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}
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}
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for(int i=0;i<m_faces.size();i++)
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{
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int numVertices = m_faces[i].m_indices.size();
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int NbTris = numVertices-2;
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const btVector3& p0 = m_vertices[m_faces[i].m_indices[0]];
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for(int j=1;j<=NbTris;j++)
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{
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int k = (j+1)%numVertices;
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const btVector3& p1 = m_vertices[m_faces[i].m_indices[j]];
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const btVector3& p2 = m_vertices[m_faces[i].m_indices[k]];
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float Area = ((p0 - p1).cross(p0 - p2)).length() * 0.5f;
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btVector3 Center = (p0+p1+p2)/3.0f;
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m_localCenter += Area * Center;
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TotalArea += Area;
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}
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}
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m_localCenter /= TotalArea;
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}
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void btConvexPolyhedron::project(const btTransform& trans, const btVector3& dir, float& min, float& max) const
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{
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min = FLT_MAX;
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max = -FLT_MAX;
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int numVerts = m_vertices.size();
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for(int i=0;i<numVerts;i++)
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{
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btVector3 pt = trans * m_vertices[i];
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float dp = pt.dot(dir);
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if(dp < min) min = dp;
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if(dp > max) max = dp;
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}
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if(min>max)
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{
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float tmp = min;
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min = max;
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max = tmp;
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}
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}
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54
src/BulletCollision/CollisionShapes/btConvexPolyhedron.h
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54
src/BulletCollision/CollisionShapes/btConvexPolyhedron.h
Normal file
@@ -0,0 +1,54 @@
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/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2011 Advanced Micro Devices, Inc. http://bulletphysics.org
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
|
||||
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
|
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3. This notice may not be removed or altered from any source distribution.
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*/
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///This file was written by Erwin Coumans
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#ifndef _BT_POLYHEDRAL_FEATURES_H
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#define _BT_POLYHEDRAL_FEATURES_H
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#include "LinearMath/btTransform.h"
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#include "LinearMath/btAlignedObjectArray.h"
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struct btFace
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{
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btAlignedObjectArray<int> m_indices;
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btAlignedObjectArray<int> m_connectedFaces;
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float m_plane[4];
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};
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class btConvexPolyhedron
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{
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public:
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btConvexPolyhedron();
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virtual ~btConvexPolyhedron();
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btAlignedObjectArray<btVector3> m_vertices;
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btAlignedObjectArray<btFace> m_faces;
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btAlignedObjectArray<btVector3> m_uniqueEdges;
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btVector3 m_localCenter;
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void initialize();
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void project(const btTransform& trans, const btVector3& dir, float& min, float& max) const;
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};
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#endif //_BT_POLYHEDRAL_FEATURES_H
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@@ -14,12 +14,140 @@ subject to the following restrictions:
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*/
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#include "BulletCollision/CollisionShapes/btPolyhedralConvexShape.h"
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#include "btConvexPolyhedron.h"
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#include "LinearMath/btConvexHullComputer.h"
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#include <new.h>
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btPolyhedralConvexShape::btPolyhedralConvexShape() :btConvexInternalShape()
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btPolyhedralConvexShape::btPolyhedralConvexShape() :btConvexInternalShape(),
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m_polyhedron(0)
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{
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}
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btPolyhedralConvexShape::~btPolyhedralConvexShape()
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{
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if (m_polyhedron)
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{
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btAlignedFree(m_polyhedron);
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}
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}
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bool btPolyhedralConvexShape::initializePolyhedralFeatures()
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{
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if (m_polyhedron)
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btAlignedFree(m_polyhedron);
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void* mem = btAlignedAlloc(sizeof(btConvexPolyhedron),16);
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m_polyhedron = new (mem) btConvexPolyhedron;
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btAlignedObjectArray<btVector3> tmpVertices;
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for (int i=0;i<getNumVertices();i++)
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{
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btVector3& newVertex = tmpVertices.expand();
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getVertex(i,newVertex);
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}
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btConvexHullComputer conv;
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conv.compute(&tmpVertices[0].getX(), sizeof(btVector3),tmpVertices.size(),0.f,0.f);
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btAlignedObjectArray<btVector3> faceNormals;
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int numFaces = conv.faces.size();
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faceNormals.resize(numFaces);
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btConvexHullComputer* convexUtil = &conv;
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m_polyhedron->m_faces.resize(numFaces);
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int numVertices = convexUtil->vertices.size();
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m_polyhedron->m_vertices.resize(numVertices);
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for (int p=0;p<numVertices;p++)
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{
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m_polyhedron->m_vertices[p] = convexUtil->vertices[p];
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}
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for (int i=0;i<numFaces;i++)
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{
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int face = convexUtil->faces[i];
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//printf("face=%d\n",face);
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const btConvexHullComputer::Edge* firstEdge = &convexUtil->edges[face];
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const btConvexHullComputer::Edge* edge = firstEdge;
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btVector3 edges[3];
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int numEdges = 0;
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//compute face normals
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btScalar maxCross2 = 0.f;
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int chosenEdge = -1;
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do
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{
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int src = edge->getSourceVertex();
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m_polyhedron->m_faces[i].m_indices.push_back(src);
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int targ = edge->getTargetVertex();
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btVector3 wa = convexUtil->vertices[src];
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btVector3 wb = convexUtil->vertices[targ];
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btVector3 newEdge = wb-wa;
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if (!newEdge.fuzzyZero())
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{
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newEdge.normalize();
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if (!numEdges)
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{
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edges[numEdges++] = newEdge;
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} else
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{
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btVector3 cr = (edges[0].cross(newEdge));
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btScalar cr2 = cr.length2();
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if (cr2 > maxCross2)
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{
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chosenEdge = m_polyhedron->m_faces[i].m_indices.size();
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numEdges=1;//replace current edge
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edges[numEdges++] = newEdge;
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maxCross2=cr2;
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}
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}
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}
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edge = edge->getNextEdgeOfFace();
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} while (edge!=firstEdge);
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btScalar planeEq = 1e30f;
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if (numEdges==2)
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{
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faceNormals[i] = edges[0].cross(edges[1]);
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faceNormals[i].normalize();
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m_polyhedron->m_faces[i].m_plane[0] = -faceNormals[i].getX();
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m_polyhedron->m_faces[i].m_plane[1] = -faceNormals[i].getY();
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m_polyhedron->m_faces[i].m_plane[2] = -faceNormals[i].getZ();
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m_polyhedron->m_faces[i].m_plane[3] = planeEq;
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}
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else
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{
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btAssert(0);//degenerate?
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faceNormals[i].setZero();
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}
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for (int v=0;v<m_polyhedron->m_faces[i].m_indices.size();v++)
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{
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btScalar eq = m_polyhedron->m_vertices[m_polyhedron->m_faces[i].m_indices[v]].dot(faceNormals[i]);
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if (planeEq>eq)
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{
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planeEq=eq;
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}
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}
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m_polyhedron->m_faces[i].m_plane[3] = planeEq;
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}
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m_polyhedron->initialize();
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return true;
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}
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btVector3 btPolyhedralConvexShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0)const
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{
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@@ -191,3 +319,6 @@ void btPolyhedralConvexAabbCachingShape::recalcLocalAabb()
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#endif
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}
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@@ -18,18 +18,32 @@ subject to the following restrictions:
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#include "LinearMath/btMatrix3x3.h"
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#include "btConvexInternalShape.h"
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class btConvexPolyhedron;
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///The btPolyhedralConvexShape is an internal interface class for polyhedral convex shapes.
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class btPolyhedralConvexShape : public btConvexInternalShape
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{
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protected:
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btConvexPolyhedron* m_polyhedron;
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public:
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btPolyhedralConvexShape();
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virtual ~btPolyhedralConvexShape();
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///optional method mainly used to generate multiple contact points by clipping polyhedral features (faces/edges)
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virtual bool initializePolyhedralFeatures();
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const btConvexPolyhedron* getConvexPolyhedron() const
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{
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return m_polyhedron;
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}
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//brute force implementations
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virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3& vec)const;
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Reference in New Issue
Block a user