Bullet Collision Detection & Physics Library
btConvexPlaneCollisionAlgorithm.cpp
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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 
17 
23 
24 //#include <stdio.h>
25 
26 btConvexPlaneCollisionAlgorithm::btConvexPlaneCollisionAlgorithm(btPersistentManifold* mf, const btCollisionAlgorithmConstructionInfo& ci, const btCollisionObjectWrapper* col0Wrap, const btCollisionObjectWrapper* col1Wrap, bool isSwapped, int numPerturbationIterations, int minimumPointsPerturbationThreshold)
28  m_ownManifold(false),
29  m_manifoldPtr(mf),
30  m_isSwapped(isSwapped),
31  m_numPerturbationIterations(numPerturbationIterations),
32  m_minimumPointsPerturbationThreshold(minimumPointsPerturbationThreshold)
33 {
34  const btCollisionObjectWrapper* convexObjWrap = m_isSwapped ? col1Wrap : col0Wrap;
35  const btCollisionObjectWrapper* planeObjWrap = m_isSwapped ? col0Wrap : col1Wrap;
36 
37  if (!m_manifoldPtr && m_dispatcher->needsCollision(convexObjWrap->getCollisionObject(), planeObjWrap->getCollisionObject()))
38  {
40  m_ownManifold = true;
41  }
42 }
43 
45 {
46  if (m_ownManifold)
47  {
48  if (m_manifoldPtr)
50  }
51 }
52 
53 void btConvexPlaneCollisionAlgorithm::collideSingleContact(const btQuaternion& perturbeRot, const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
54 {
55  const btCollisionObjectWrapper* convexObjWrap = m_isSwapped ? body1Wrap : body0Wrap;
56  const btCollisionObjectWrapper* planeObjWrap = m_isSwapped ? body0Wrap : body1Wrap;
57 
58  btConvexShape* convexShape = (btConvexShape*)convexObjWrap->getCollisionShape();
59  btStaticPlaneShape* planeShape = (btStaticPlaneShape*)planeObjWrap->getCollisionShape();
60 
61  bool hasCollision = false;
62  const btVector3& planeNormal = planeShape->getPlaneNormal();
63  const btScalar& planeConstant = planeShape->getPlaneConstant();
64 
65  btTransform convexWorldTransform = convexObjWrap->getWorldTransform();
66  btTransform convexInPlaneTrans;
67  convexInPlaneTrans = planeObjWrap->getWorldTransform().inverse() * convexWorldTransform;
68  //now perturbe the convex-world transform
69  convexWorldTransform.getBasis() *= btMatrix3x3(perturbeRot);
70  btTransform planeInConvex;
71  planeInConvex = convexWorldTransform.inverse() * planeObjWrap->getWorldTransform();
72 
73  btVector3 vtx = convexShape->localGetSupportingVertex(planeInConvex.getBasis() * -planeNormal);
74 
75  btVector3 vtxInPlane = convexInPlaneTrans(vtx);
76  btScalar distance = (planeNormal.dot(vtxInPlane) - planeConstant);
77 
78  btVector3 vtxInPlaneProjected = vtxInPlane - distance * planeNormal;
79  btVector3 vtxInPlaneWorld = planeObjWrap->getWorldTransform() * vtxInPlaneProjected;
80 
81  hasCollision = distance < m_manifoldPtr->getContactBreakingThreshold();
83  if (hasCollision)
84  {
86  btVector3 normalOnSurfaceB = planeObjWrap->getWorldTransform().getBasis() * planeNormal;
87  btVector3 pOnB = vtxInPlaneWorld;
88  resultOut->addContactPoint(normalOnSurfaceB, pOnB, distance);
89  }
90 }
91 
93 {
94  (void)dispatchInfo;
95  if (!m_manifoldPtr)
96  return;
97 
98  const btCollisionObjectWrapper* convexObjWrap = m_isSwapped ? body1Wrap : body0Wrap;
99  const btCollisionObjectWrapper* planeObjWrap = m_isSwapped ? body0Wrap : body1Wrap;
100 
101  btConvexShape* convexShape = (btConvexShape*)convexObjWrap->getCollisionShape();
102  btStaticPlaneShape* planeShape = (btStaticPlaneShape*)planeObjWrap->getCollisionShape();
103 
104  bool hasCollision = false;
105  const btVector3& planeNormal = planeShape->getPlaneNormal();
106  const btScalar& planeConstant = planeShape->getPlaneConstant();
107  btTransform planeInConvex;
108  planeInConvex = convexObjWrap->getWorldTransform().inverse() * planeObjWrap->getWorldTransform();
109  btTransform convexInPlaneTrans;
110  convexInPlaneTrans = planeObjWrap->getWorldTransform().inverse() * convexObjWrap->getWorldTransform();
111 
112  btVector3 vtx = convexShape->localGetSupportingVertex(planeInConvex.getBasis() * -planeNormal);
113  btVector3 vtxInPlane = convexInPlaneTrans(vtx);
114  btScalar distance = (planeNormal.dot(vtxInPlane) - planeConstant);
115 
116  btVector3 vtxInPlaneProjected = vtxInPlane - distance * planeNormal;
117  btVector3 vtxInPlaneWorld = planeObjWrap->getWorldTransform() * vtxInPlaneProjected;
118 
119  hasCollision = distance < m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
121  if (hasCollision)
122  {
124  btVector3 normalOnSurfaceB = planeObjWrap->getWorldTransform().getBasis() * planeNormal;
125  btVector3 pOnB = vtxInPlaneWorld;
126  resultOut->addContactPoint(normalOnSurfaceB, pOnB, distance);
127  }
128 
129  //the perturbation algorithm doesn't work well with implicit surfaces such as spheres, cylinder and cones:
130  //they keep on rolling forever because of the additional off-center contact points
131  //so only enable the feature for polyhedral shapes (btBoxShape, btConvexHullShape etc)
133  {
134  btVector3 v0, v1;
135  btPlaneSpace1(planeNormal, v0, v1);
136  //now perform 'm_numPerturbationIterations' collision queries with the perturbated collision objects
137 
138  const btScalar angleLimit = 0.125f * SIMD_PI;
139  btScalar perturbeAngle;
140  btScalar radius = convexShape->getAngularMotionDisc();
141  perturbeAngle = gContactBreakingThreshold / radius;
142  if (perturbeAngle > angleLimit)
143  perturbeAngle = angleLimit;
144 
145  btQuaternion perturbeRot(v0, perturbeAngle);
146  for (int i = 0; i < m_numPerturbationIterations; i++)
147  {
148  btScalar iterationAngle = i * (SIMD_2_PI / btScalar(m_numPerturbationIterations));
149  btQuaternion rotq(planeNormal, iterationAngle);
150  collideSingleContact(rotq.inverse() * perturbeRot * rotq, body0Wrap, body1Wrap, dispatchInfo, resultOut);
151  }
152  }
153 
154  if (m_ownManifold)
155  {
157  {
158  resultOut->refreshContactPoints();
159  }
160  }
161 }
162 
164 {
165  (void)resultOut;
166  (void)dispatchInfo;
167  (void)col0;
168  (void)col1;
169 
170  //not yet
171  return btScalar(1.);
172 }
virtual void releaseManifold(btPersistentManifold *manifold)=0
btPersistentManifold is a contact point cache, it stays persistent as long as objects are overlapping...
btScalar getContactBreakingThreshold() const
virtual btVector3 localGetSupportingVertex(const btVector3 &vec) const =0
virtual void processCollision(const btCollisionObjectWrapper *body0Wrap, const btCollisionObjectWrapper *body1Wrap, const btDispatcherInfo &dispatchInfo, btManifoldResult *resultOut)
const btScalar & getPlaneConstant() const
void setPersistentManifold(btPersistentManifold *manifoldPtr)
void btPlaneSpace1(const T &n, T &p, T &q)
Definition: btVector3.h:1251
btManifoldResult is a helper class to manage contact results.
const btCollisionShape * getCollisionShape() const
virtual btScalar calculateTimeOfImpact(btCollisionObject *body0, btCollisionObject *body1, const btDispatcherInfo &dispatchInfo, btManifoldResult *resultOut)
The btConvexShape is an abstract shape interface, implemented by all convex shapes such as btBoxShape...
Definition: btConvexShape.h:31
virtual void addContactPoint(const btVector3 &normalOnBInWorld, const btVector3 &pointInWorld, btScalar depth)
#define SIMD_PI
Definition: btScalar.h:506
btScalar m_closestPointDistanceThreshold
#define SIMD_2_PI
Definition: btScalar.h:507
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:229
const btCollisionObject * getCollisionObject() const
btCollisionObject can be used to manage collision detection objects.
btMatrix3x3 & getBasis()
Return the basis matrix for the rotation.
Definition: btTransform.h:108
virtual btPersistentManifold * getNewManifold(const btCollisionObject *b0, const btCollisionObject *b1)=0
btConvexPlaneCollisionAlgorithm(btPersistentManifold *mf, const btCollisionAlgorithmConstructionInfo &ci, const btCollisionObjectWrapper *body0Wrap, const btCollisionObjectWrapper *body1Wrap, bool isSwapped, int numPerturbationIterations, int minimumPointsPerturbationThreshold)
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:80
void collideSingleContact(const btQuaternion &perturbeRot, const btCollisionObjectWrapper *body0Wrap, const btCollisionObjectWrapper *body1Wrap, const btDispatcherInfo &dispatchInfo, btManifoldResult *resultOut)
bool isPolyhedral() const
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:28
const btVector3 & getPlaneNormal() const
const btTransform & getWorldTransform() const
The btMatrix3x3 class implements a 3x3 rotation matrix, to perform linear algebra in combination with...
Definition: btMatrix3x3.h:46
virtual btScalar getAngularMotionDisc() const
getAngularMotionDisc returns the maximum radius needed for Conservative Advancement to handle time-of...
The btQuaternion implements quaternion to perform linear algebra rotations in combination with btMatr...
Definition: btQuaternion.h:49
The btStaticPlaneShape simulates an infinite non-moving (static) collision plane. ...
virtual bool needsCollision(const btCollisionObject *body0, const btCollisionObject *body1)=0
btCollisionAlgorithm is an collision interface that is compatible with the Broadphase and btDispatche...
const btPersistentManifold * getPersistentManifold() const
btScalar gContactBreakingThreshold
btTransform inverse() const
Return the inverse of this transform.
Definition: btTransform.h:182
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:294