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
16 #include "btConvexPlaneCollisionAlgorithm.h"
17
18 #include "BulletCollision/CollisionDispatch/btCollisionDispatcher.h"
19 #include "BulletCollision/CollisionDispatch/btCollisionObject.h"
20 #include "BulletCollision/CollisionShapes/btConvexShape.h"
21 #include "BulletCollision/CollisionShapes/btStaticPlaneShape.h"
22 #include "BulletCollision/CollisionDispatch/btCollisionObjectWrapper.h"
23
24 //#include <stdio.h>
25
btConvexPlaneCollisionAlgorithm(btPersistentManifold * mf,const btCollisionAlgorithmConstructionInfo & ci,const btCollisionObjectWrapper * col0Wrap,const btCollisionObjectWrapper * col1Wrap,bool isSwapped,int numPerturbationIterations,int minimumPointsPerturbationThreshold)26 btConvexPlaneCollisionAlgorithm::btConvexPlaneCollisionAlgorithm(btPersistentManifold* mf,const btCollisionAlgorithmConstructionInfo& ci,const btCollisionObjectWrapper* col0Wrap,const btCollisionObjectWrapper* col1Wrap, bool isSwapped, int numPerturbationIterations,int minimumPointsPerturbationThreshold)
27 : btCollisionAlgorithm(ci),
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 {
39 m_manifoldPtr = m_dispatcher->getNewManifold(convexObjWrap->getCollisionObject(),planeObjWrap->getCollisionObject());
40 m_ownManifold = true;
41 }
42 }
43
44
~btConvexPlaneCollisionAlgorithm()45 btConvexPlaneCollisionAlgorithm::~btConvexPlaneCollisionAlgorithm()
46 {
47 if (m_ownManifold)
48 {
49 if (m_manifoldPtr)
50 m_dispatcher->releaseManifold(m_manifoldPtr);
51 }
52 }
53
collideSingleContact(const btQuaternion & perturbeRot,const btCollisionObjectWrapper * body0Wrap,const btCollisionObjectWrapper * body1Wrap,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)54 void btConvexPlaneCollisionAlgorithm::collideSingleContact (const btQuaternion& perturbeRot, const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
55 {
56 const btCollisionObjectWrapper* convexObjWrap = m_isSwapped? body1Wrap : body0Wrap;
57 const btCollisionObjectWrapper* planeObjWrap = m_isSwapped? body0Wrap: body1Wrap;
58
59 btConvexShape* convexShape = (btConvexShape*) convexObjWrap->getCollisionShape();
60 btStaticPlaneShape* planeShape = (btStaticPlaneShape*) planeObjWrap->getCollisionShape();
61
62 bool hasCollision = false;
63 const btVector3& planeNormal = planeShape->getPlaneNormal();
64 const btScalar& planeConstant = planeShape->getPlaneConstant();
65
66 btTransform convexWorldTransform = convexObjWrap->getWorldTransform();
67 btTransform convexInPlaneTrans;
68 convexInPlaneTrans= planeObjWrap->getWorldTransform().inverse() * convexWorldTransform;
69 //now perturbe the convex-world transform
70 convexWorldTransform.getBasis()*=btMatrix3x3(perturbeRot);
71 btTransform planeInConvex;
72 planeInConvex= convexWorldTransform.inverse() * planeObjWrap->getWorldTransform();
73
74 btVector3 vtx = convexShape->localGetSupportingVertex(planeInConvex.getBasis()*-planeNormal);
75
76 btVector3 vtxInPlane = convexInPlaneTrans(vtx);
77 btScalar distance = (planeNormal.dot(vtxInPlane) - planeConstant);
78
79 btVector3 vtxInPlaneProjected = vtxInPlane - distance*planeNormal;
80 btVector3 vtxInPlaneWorld = planeObjWrap->getWorldTransform() * vtxInPlaneProjected;
81
82 hasCollision = distance < m_manifoldPtr->getContactBreakingThreshold();
83 resultOut->setPersistentManifold(m_manifoldPtr);
84 if (hasCollision)
85 {
86 /// report a contact. internally this will be kept persistent, and contact reduction is done
87 btVector3 normalOnSurfaceB = planeObjWrap->getWorldTransform().getBasis() * planeNormal;
88 btVector3 pOnB = vtxInPlaneWorld;
89 resultOut->addContactPoint(normalOnSurfaceB,pOnB,distance);
90 }
91 }
92
93
processCollision(const btCollisionObjectWrapper * body0Wrap,const btCollisionObjectWrapper * body1Wrap,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)94 void btConvexPlaneCollisionAlgorithm::processCollision (const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
95 {
96 (void)dispatchInfo;
97 if (!m_manifoldPtr)
98 return;
99
100 const btCollisionObjectWrapper* convexObjWrap = m_isSwapped? body1Wrap : body0Wrap;
101 const btCollisionObjectWrapper* planeObjWrap = m_isSwapped? body0Wrap: body1Wrap;
102
103 btConvexShape* convexShape = (btConvexShape*) convexObjWrap->getCollisionShape();
104 btStaticPlaneShape* planeShape = (btStaticPlaneShape*) planeObjWrap->getCollisionShape();
105
106 bool hasCollision = false;
107 const btVector3& planeNormal = planeShape->getPlaneNormal();
108 const btScalar& planeConstant = planeShape->getPlaneConstant();
109 btTransform planeInConvex;
110 planeInConvex= convexObjWrap->getWorldTransform().inverse() * planeObjWrap->getWorldTransform();
111 btTransform convexInPlaneTrans;
112 convexInPlaneTrans= planeObjWrap->getWorldTransform().inverse() * convexObjWrap->getWorldTransform();
113
114 btVector3 vtx = convexShape->localGetSupportingVertex(planeInConvex.getBasis()*-planeNormal);
115 btVector3 vtxInPlane = convexInPlaneTrans(vtx);
116 btScalar distance = (planeNormal.dot(vtxInPlane) - planeConstant);
117
118 btVector3 vtxInPlaneProjected = vtxInPlane - distance*planeNormal;
119 btVector3 vtxInPlaneWorld = planeObjWrap->getWorldTransform() * vtxInPlaneProjected;
120
121 hasCollision = distance < m_manifoldPtr->getContactBreakingThreshold();
122 resultOut->setPersistentManifold(m_manifoldPtr);
123 if (hasCollision)
124 {
125 /// report a contact. internally this will be kept persistent, and contact reduction is done
126 btVector3 normalOnSurfaceB = planeObjWrap->getWorldTransform().getBasis() * planeNormal;
127 btVector3 pOnB = vtxInPlaneWorld;
128 resultOut->addContactPoint(normalOnSurfaceB,pOnB,distance);
129 }
130
131 //the perturbation algorithm doesn't work well with implicit surfaces such as spheres, cylinder and cones:
132 //they keep on rolling forever because of the additional off-center contact points
133 //so only enable the feature for polyhedral shapes (btBoxShape, btConvexHullShape etc)
134 if (convexShape->isPolyhedral() && resultOut->getPersistentManifold()->getNumContacts()<m_minimumPointsPerturbationThreshold)
135 {
136 btVector3 v0,v1;
137 btPlaneSpace1(planeNormal,v0,v1);
138 //now perform 'm_numPerturbationIterations' collision queries with the perturbated collision objects
139
140 const btScalar angleLimit = 0.125f * SIMD_PI;
141 btScalar perturbeAngle;
142 btScalar radius = convexShape->getAngularMotionDisc();
143 perturbeAngle = gContactBreakingThreshold / radius;
144 if ( perturbeAngle > angleLimit )
145 perturbeAngle = angleLimit;
146
147 btQuaternion perturbeRot(v0,perturbeAngle);
148 for (int i=0;i<m_numPerturbationIterations;i++)
149 {
150 btScalar iterationAngle = i*(SIMD_2_PI/btScalar(m_numPerturbationIterations));
151 btQuaternion rotq(planeNormal,iterationAngle);
152 collideSingleContact(rotq.inverse()*perturbeRot*rotq,body0Wrap,body1Wrap,dispatchInfo,resultOut);
153 }
154 }
155
156 if (m_ownManifold)
157 {
158 if (m_manifoldPtr->getNumContacts())
159 {
160 resultOut->refreshContactPoints();
161 }
162 }
163 }
164
calculateTimeOfImpact(btCollisionObject * col0,btCollisionObject * col1,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)165 btScalar btConvexPlaneCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* col0,btCollisionObject* col1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
166 {
167 (void)resultOut;
168 (void)dispatchInfo;
169 (void)col0;
170 (void)col1;
171
172 //not yet
173 return btScalar(1.);
174 }
175