1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2006 Erwin Coumans https://bulletphysics.org
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
~btConvexPlaneCollisionAlgorithm()44 btConvexPlaneCollisionAlgorithm::~btConvexPlaneCollisionAlgorithm()
45 {
46 if (m_ownManifold)
47 {
48 if (m_manifoldPtr)
49 m_dispatcher->releaseManifold(m_manifoldPtr);
50 }
51 }
52
collideSingleContact(const btQuaternion & perturbeRot,const btCollisionObjectWrapper * body0Wrap,const btCollisionObjectWrapper * body1Wrap,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)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();
82 resultOut->setPersistentManifold(m_manifoldPtr);
83 if (hasCollision)
84 {
85 /// report a contact. internally this will be kept persistent, and contact reduction is done
86 btVector3 normalOnSurfaceB = planeObjWrap->getWorldTransform().getBasis() * planeNormal;
87 btVector3 pOnB = vtxInPlaneWorld;
88 resultOut->addContactPoint(normalOnSurfaceB, pOnB, distance);
89 }
90 }
91
processCollision(const btCollisionObjectWrapper * body0Wrap,const btCollisionObjectWrapper * body1Wrap,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)92 void btConvexPlaneCollisionAlgorithm::processCollision(const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
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;
120 resultOut->setPersistentManifold(m_manifoldPtr);
121 if (hasCollision)
122 {
123 /// report a contact. internally this will be kept persistent, and contact reduction is done
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)
132 if (convexShape->isPolyhedral() && resultOut->getPersistentManifold()->getNumContacts() < m_minimumPointsPerturbationThreshold)
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 {
156 if (m_manifoldPtr->getNumContacts())
157 {
158 resultOut->refreshContactPoints();
159 }
160 }
161 }
162
calculateTimeOfImpact(btCollisionObject * col0,btCollisionObject * col1,const btDispatcherInfo & dispatchInfo,btManifoldResult * resultOut)163 btScalar btConvexPlaneCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* col0, btCollisionObject* col1, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
164 {
165 (void)resultOut;
166 (void)dispatchInfo;
167 (void)col0;
168 (void)col1;
169
170 //not yet
171 return btScalar(1.);
172 }
173