src/BulletCollision/CollisionDispatch/btConvexPlaneCollisionAlgorithm.cpp

   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
  23 //#include <stdio.h>
  24
  25 btConvexPlaneCollisionAlgorithm::btConvexPlaneCollisionAlgorithm(btPersistentManifold* mf,const btCollisionAlgorithmConstructionInfo& ci,btCollisionObject* col0,btCollisionObject* col1, bool isSwapped, int numPerturbationIterations,int minimumPointsPerturbationThreshold)
  26 : btCollisionAlgorithm(ci),
  27 m_ownManifold(false),
  28 m_manifoldPtr(mf),
  29 m_isSwapped(isSwapped),
  30 m_numPerturbationIterations(numPerturbationIterations),
  31 m_minimumPointsPerturbationThreshold(minimumPointsPerturbationThreshold)
  32 {
  33         btCollisionObject* convexObj = m_isSwapped? col1 : col0;
  34         btCollisionObject* planeObj = m_isSwapped? col0 : col1;
  35
  36         if (!m_manifoldPtr && m_dispatcher->needsCollision(convexObj,planeObj))
  37         {
  38                 m_manifoldPtr = m_dispatcher->getNewManifold(convexObj,planeObj);
  39                 m_ownManifold = true;
  40         }
  41 }
  42
  43
  44 btConvexPlaneCollisionAlgorithm::~btConvexPlaneCollisionAlgorithm()
  45 {
  46         if (m_ownManifold)
  47         {
  48                 if (m_manifoldPtr)
  49                         m_dispatcher->releaseManifold(m_manifoldPtr);
  50         }
  51 }
  52
  53 void btConvexPlaneCollisionAlgorithm::collideSingleContact (const btQuaternion& perturbeRot, btCollisionObject* body0,btCollisionObject* body1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
  54 {
  55     btCollisionObject* convexObj = m_isSwapped? body1 : body0;
  56         btCollisionObject* planeObj = m_isSwapped? body0: body1;
  57
  58         btConvexShape* convexShape = (btConvexShape*) convexObj->getCollisionShape();
  59         btStaticPlaneShape* planeShape = (btStaticPlaneShape*) planeObj->getCollisionShape();
  60
  61     bool hasCollision = false;
  62         const btVector3& planeNormal = planeShape->getPlaneNormal();
  63         const btScalar& planeConstant = planeShape->getPlaneConstant();
  64
  65         btTransform convexWorldTransform = convexObj->getWorldTransform();
  66         btTransform convexInPlaneTrans;
  67         convexInPlaneTrans= planeObj->getWorldTransform().inverse() * convexWorldTransform;
  68         //now perturbe the convex-world transform
  69         convexWorldTransform.getBasis()*=btMatrix3x3(perturbeRot);
  70         btTransform planeInConvex;
  71         planeInConvex= convexWorldTransform.inverse() * planeObj->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 = planeObj->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 = planeObj->getWorldTransform().getBasis() * planeNormal;
  87                 btVector3 pOnB = vtxInPlaneWorld;
  88                 resultOut->addContactPoint(normalOnSurfaceB,pOnB,distance);
  89         }
  90 }
  91
  92
  93 void btConvexPlaneCollisionAlgorithm::processCollision (btCollisionObject* body0,btCollisionObject* body1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
  94 {
  95         (void)dispatchInfo;
  96         if (!m_manifoldPtr)
  97                 return;
  98
  99         btCollisionObject* convexObj = m_isSwapped? body1 : body0;
 100         btCollisionObject* planeObj = m_isSwapped? body0: body1;
 101
 102         btConvexShape* convexShape = (btConvexShape*) convexObj->getCollisionShape();
 103         btStaticPlaneShape* planeShape = (btStaticPlaneShape*) planeObj->getCollisionShape();
 104
 105         bool hasCollision = false;
 106         const btVector3& planeNormal = planeShape->getPlaneNormal();
 107         const btScalar& planeConstant = planeShape->getPlaneConstant();
 108         btTransform planeInConvex;
 109         planeInConvex= convexObj->getWorldTransform().inverse() * planeObj->getWorldTransform();
 110         btTransform convexInPlaneTrans;
 111         convexInPlaneTrans= planeObj->getWorldTransform().inverse() * convexObj->getWorldTransform();
 112
 113         btVector3 vtx = convexShape->localGetSupportingVertex(planeInConvex.getBasis()*-planeNormal);
 114         btVector3 vtxInPlane = convexInPlaneTrans(vtx);
 115         btScalar distance = (planeNormal.dot(vtxInPlane) - planeConstant);
 116
 117         btVector3 vtxInPlaneProjected = vtxInPlane - distance*planeNormal;
 118         btVector3 vtxInPlaneWorld = planeObj->getWorldTransform() * vtxInPlaneProjected;
 119
 120         hasCollision = distance < m_manifoldPtr->getContactBreakingThreshold();
 121         resultOut->setPersistentManifold(m_manifoldPtr);
 122         if (hasCollision)
 123         {
 124                 /// report a contact. internally this will be kept persistent, and contact reduction is done
 125                 btVector3 normalOnSurfaceB = planeObj->getWorldTransform().getBasis() * planeNormal;
 126                 btVector3 pOnB = vtxInPlaneWorld;
 127                 resultOut->addContactPoint(normalOnSurfaceB,pOnB,distance);
 128         }
 129
 130         //the perturbation algorithm doesn't work well with implicit surfaces such as spheres, cylinder and cones:
 131         //they keep on rolling forever because of the additional off-center contact points
 132         //so only enable the feature for polyhedral shapes (btBoxShape, btConvexHullShape etc)
 133         if (convexShape->isPolyhedral() && resultOut->getPersistentManifold()->getNumContacts()<m_minimumPointsPerturbationThreshold)
 134         {
 135                 btVector3 v0,v1;
 136                 btPlaneSpace1(planeNormal,v0,v1);
 137                 //now perform 'm_numPerturbationIterations' collision queries with the perturbated collision objects
 138
 139                 const btScalar angleLimit = 0.125f * SIMD_PI;
 140                 btScalar perturbeAngle;
 141                 btScalar radius = convexShape->getAngularMotionDisc();
 142                 perturbeAngle = gContactBreakingThreshold / radius;
 143                 if ( perturbeAngle > angleLimit )
 144                                 perturbeAngle = angleLimit;
 145
 146                 btQuaternion perturbeRot(v0,perturbeAngle);
 147                 for (int i=0;i<m_numPerturbationIterations;i++)
 148                 {
 149                         btScalar iterationAngle = i*(SIMD_2_PI/btScalar(m_numPerturbationIterations));
 150                         btQuaternion rotq(planeNormal,iterationAngle);
 151                         collideSingleContact(rotq.inverse()*perturbeRot*rotq,body0,body1,dispatchInfo,resultOut);
 152                 }
 153         }
 154
 155         if (m_ownManifold)
 156         {
 157                 if (m_manifoldPtr->getNumContacts())
 158                 {
 159                         resultOut->refreshContactPoints();
 160                 }
 161         }
 162 }
 163
 164 btScalar btConvexPlaneCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* col0,btCollisionObject* col1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
 165 {
 166         (void)resultOut;
 167         (void)dispatchInfo;
 168         (void)col0;
 169         (void)col1;
 170
 171         //not yet
 172         return btScalar(1.);
 173 }