Bullet Collision Detection & Physics Library
btManifoldResult.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 
16 
17 #include "btManifoldResult.h"
21 
24 
25 
26 
28 {
29  btScalar friction = body0->getRollingFriction() * body1->getFriction() + body1->getRollingFriction() * body0->getFriction();
30 
31  const btScalar MAX_FRICTION = btScalar(10.);
32  if (friction < -MAX_FRICTION)
33  friction = -MAX_FRICTION;
34  if (friction > MAX_FRICTION)
35  friction = MAX_FRICTION;
36  return friction;
37 
38 }
39 
41 {
42  btScalar friction = body0->getSpinningFriction() * body1->getFriction() + body1->getSpinningFriction() * body0->getFriction();
43 
44  const btScalar MAX_FRICTION = btScalar(10.);
45  if (friction < -MAX_FRICTION)
46  friction = -MAX_FRICTION;
47  if (friction > MAX_FRICTION)
48  friction = MAX_FRICTION;
49  return friction;
50 }
51 
54 {
55  btScalar friction = body0->getFriction() * body1->getFriction();
56 
57  const btScalar MAX_FRICTION = btScalar(10.);
58  if (friction < -MAX_FRICTION)
59  friction = -MAX_FRICTION;
60  if (friction > MAX_FRICTION)
61  friction = MAX_FRICTION;
62  return friction;
63 
64 }
65 
67 {
68  return body0->getRestitution() * body1->getRestitution();
69 }
70 
72 {
73  return body0->getContactDamping() + body1->getContactDamping();
74 }
75 
77 {
78 
79  btScalar s0 = body0->getContactStiffness();
80  btScalar s1 = body1->getContactStiffness();
81 
82  btScalar tmp0 = btScalar(1)/s0;
83  btScalar tmp1 = btScalar(1)/s1;
84  btScalar combinedStiffness = btScalar(1) / (tmp0+tmp1);
85  return combinedStiffness;
86 }
87 
88 
90  :m_manifoldPtr(0),
91  m_body0Wrap(body0Wrap),
92  m_body1Wrap(body1Wrap)
93 #ifdef DEBUG_PART_INDEX
94  ,m_partId0(-1),
95  m_partId1(-1),
96  m_index0(-1),
97  m_index1(-1)
98 #endif //DEBUG_PART_INDEX
99  , m_closestPointDistanceThreshold(0)
100 {
101 }
102 
103 
104 void btManifoldResult::addContactPoint(const btVector3& normalOnBInWorld,const btVector3& pointInWorld,btScalar depth)
105 {
107  //order in manifold needs to match
108 
110 // if (depth > m_manifoldPtr->getContactProcessingThreshold())
111  return;
112 
113  bool isSwapped = m_manifoldPtr->getBody0() != m_body0Wrap->getCollisionObject();
114  bool isNewCollision = m_manifoldPtr->getNumContacts() == 0;
115 
116  btVector3 pointA = pointInWorld + normalOnBInWorld * depth;
117 
118  btVector3 localA;
119  btVector3 localB;
120 
121  if (isSwapped)
122  {
124  localB = m_body0Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
125  } else
126  {
128  localB = m_body1Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
129  }
130 
131  btManifoldPoint newPt(localA,localB,normalOnBInWorld,depth);
132  newPt.m_positionWorldOnA = pointA;
133  newPt.m_positionWorldOnB = pointInWorld;
134 
135  int insertIndex = m_manifoldPtr->getCacheEntry(newPt);
136 
141 
144  {
148  }
149 
152  {
154  }
155 
157 
158 
159 
160  //BP mod, store contact triangles.
161  if (isSwapped)
162  {
163  newPt.m_partId0 = m_partId1;
164  newPt.m_partId1 = m_partId0;
165  newPt.m_index0 = m_index1;
166  newPt.m_index1 = m_index0;
167  } else
168  {
169  newPt.m_partId0 = m_partId0;
170  newPt.m_partId1 = m_partId1;
171  newPt.m_index0 = m_index0;
172  newPt.m_index1 = m_index1;
173  }
174  //printf("depth=%f\n",depth);
176  if (insertIndex >= 0)
177  {
178  //const btManifoldPoint& oldPoint = m_manifoldPtr->getContactPoint(insertIndex);
179  m_manifoldPtr->replaceContactPoint(newPt,insertIndex);
180  } else
181  {
182  insertIndex = m_manifoldPtr->addManifoldPoint(newPt);
183  }
184 
185  //User can override friction and/or restitution
186  if (gContactAddedCallback &&
187  //and if either of the two bodies requires custom material
190  {
191  //experimental feature info, for per-triangle material etc.
192  const btCollisionObjectWrapper* obj0Wrap = isSwapped? m_body1Wrap : m_body0Wrap;
193  const btCollisionObjectWrapper* obj1Wrap = isSwapped? m_body0Wrap : m_body1Wrap;
194  (*gContactAddedCallback)(m_manifoldPtr->getContactPoint(insertIndex),obj0Wrap,newPt.m_partId0,newPt.m_index0,obj1Wrap,newPt.m_partId1,newPt.m_index1);
195  }
196 
197  if (gContactStartedCallback && isNewCollision)
198  {
200  }
201 }
202 
ContactStartedCallback gContactStartedCallback
btScalar getContactBreakingThreshold() const
btScalar m_combinedContactStiffness1
btVector3 m_lateralFrictionDir1
btScalar getContactDamping() const
static btScalar calculateCombinedContactDamping(const btCollisionObject *body0, const btCollisionObject *body1)
btPersistentManifold * m_manifoldPtr
btScalar m_combinedRestitution
static btScalar calculateCombinedRollingFriction(const btCollisionObject *body0, const btCollisionObject *body1)
btScalar getContactStiffness() const
void btPlaneSpace1(const T &n, T &p, T &q)
Definition: btVector3.h:1283
#define btAssert(x)
Definition: btScalar.h:131
static btScalar calculateCombinedContactStiffness(const btCollisionObject *body0, const btCollisionObject *body1)
ManifoldContactPoint collects and maintains persistent contactpoints.
const btCollisionObjectWrapper * m_body1Wrap
const btManifoldPoint & getContactPoint(int index) const
virtual void addContactPoint(const btVector3 &normalOnBInWorld, const btVector3 &pointInWorld, btScalar depth)
btScalar m_combinedRollingFriction
btTransform & getWorldTransform()
btVector3 m_normalWorldOnB
btVector3 m_positionWorldOnB
const btCollisionObject * getBody0() const
const btCollisionObject * getCollisionObject() const
btScalar getRestitution() const
btCollisionObject can be used to manage collision detection objects.
btVector3 m_positionWorldOnA
m_positionWorldOnA is redundant information, see getPositionWorldOnA(), but for clarity ...
btVector3 invXform(const btVector3 &inVec) const
Definition: btTransform.h:223
btScalar getRollingFriction() const
int getCollisionFlags() const
static btScalar calculateCombinedFriction(const btCollisionObject *body0, const btCollisionObject *body1)
User can override this material combiner by implementing gContactAddedCallback and setting body0->m_c...
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:83
bool(* ContactAddedCallback)(btManifoldPoint &cp, const btCollisionObjectWrapper *colObj0Wrap, int partId0, int index0, const btCollisionObjectWrapper *colObj1Wrap, int partId1, int index1)
btScalar m_combinedContactDamping1
btScalar getSpinningFriction() const
static btScalar calculateCombinedSpinningFriction(const btCollisionObject *body0, const btCollisionObject *body1)
ContactAddedCallback gContactAddedCallback
This is to allow MaterialCombiner/Custom Friction/Restitution values.
btScalar m_combinedFriction
const btCollisionObjectWrapper * m_body0Wrap
btVector3 m_lateralFrictionDir2
void replaceContactPoint(const btManifoldPoint &newPoint, int insertIndex)
static btScalar calculateCombinedRestitution(const btCollisionObject *body0, const btCollisionObject *body1)
in the future we can let the user override the methods to combine restitution and friction ...
btScalar getFriction() const
int addManifoldPoint(const btManifoldPoint &newPoint, bool isPredictive=false)
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:292
btScalar m_combinedSpinningFriction
int getCacheEntry(const btManifoldPoint &newPoint) const