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 #include "btManifoldResult.h"
20 
23 
30 
32 {
33  btScalar friction = body0->getRollingFriction() * body1->getFriction() + body1->getRollingFriction() * body0->getFriction();
34 
35  const btScalar MAX_FRICTION = btScalar(10.);
36  if (friction < -MAX_FRICTION)
37  friction = -MAX_FRICTION;
38  if (friction > MAX_FRICTION)
39  friction = MAX_FRICTION;
40  return friction;
41 }
42 
44 {
45  btScalar friction = body0->getSpinningFriction() * body1->getFriction() + body1->getSpinningFriction() * body0->getFriction();
46 
47  const btScalar MAX_FRICTION = btScalar(10.);
48  if (friction < -MAX_FRICTION)
49  friction = -MAX_FRICTION;
50  if (friction > MAX_FRICTION)
51  friction = MAX_FRICTION;
52  return friction;
53 }
54 
57 {
58  btScalar friction = body0->getFriction() * body1->getFriction();
59 
60  const btScalar MAX_FRICTION = btScalar(10.);
61  if (friction < -MAX_FRICTION)
62  friction = -MAX_FRICTION;
63  if (friction > MAX_FRICTION)
64  friction = MAX_FRICTION;
65  return friction;
66 }
67 
69 {
70  return body0->getRestitution() * body1->getRestitution();
71 }
72 
74 {
75  return body0->getContactDamping() + body1->getContactDamping();
76 }
77 
79 {
80  btScalar s0 = body0->getContactStiffness();
81  btScalar s1 = body1->getContactStiffness();
82 
83  btScalar tmp0 = btScalar(1) / s0;
84  btScalar tmp1 = btScalar(1) / s1;
85  btScalar combinedStiffness = btScalar(1) / (tmp0 + tmp1);
86  return combinedStiffness;
87 }
88 
90  : m_manifoldPtr(0),
91  m_body0Wrap(body0Wrap),
92  m_body1Wrap(body1Wrap)
93 #ifdef DEBUG_PART_INDEX
94  ,
95  m_partId0(-1),
96  m_partId1(-1),
97  m_index0(-1),
98  m_index1(-1)
99 #endif //DEBUG_PART_INDEX
100  ,
101  m_closestPointDistanceThreshold(0)
102 {
103 }
104 
105 void btManifoldResult::addContactPoint(const btVector3& normalOnBInWorld, const btVector3& pointInWorld, btScalar depth)
106 {
108  //order in manifold needs to match
109 
111  // if (depth > m_manifoldPtr->getContactProcessingThreshold())
112  return;
113 
114  bool isSwapped = m_manifoldPtr->getBody0() != m_body0Wrap->getCollisionObject();
115  bool isNewCollision = m_manifoldPtr->getNumContacts() == 0;
116 
117  btVector3 pointA = pointInWorld + normalOnBInWorld * depth;
118 
119  btVector3 localA;
120  btVector3 localB;
121 
122  if (isSwapped)
123  {
125  localB = m_body0Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
126  }
127  else
128  {
130  localB = m_body1Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
131  }
132 
133  btManifoldPoint newPt(localA, localB, normalOnBInWorld, depth);
134  newPt.m_positionWorldOnA = pointA;
135  newPt.m_positionWorldOnB = pointInWorld;
136 
137  int insertIndex = m_manifoldPtr->getCacheEntry(newPt);
138 
143 
146  {
150  }
151 
154  {
156  }
157 
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  }
168  else
169  {
170  newPt.m_partId0 = m_partId0;
171  newPt.m_partId1 = m_partId1;
172  newPt.m_index0 = m_index0;
173  newPt.m_index1 = m_index1;
174  }
175  //printf("depth=%f\n",depth);
177  if (insertIndex >= 0)
178  {
179  //const btManifoldPoint& oldPoint = m_manifoldPtr->getContactPoint(insertIndex);
180  m_manifoldPtr->replaceContactPoint(newPt, insertIndex);
181  }
182  else
183  {
184  insertIndex = m_manifoldPtr->addManifoldPoint(newPt);
185  }
186 
187  //User can override friction and/or restitution
188  if (gContactAddedCallback &&
189  //and if either of the two bodies requires custom material
192  {
193  //experimental feature info, for per-triangle material etc.
194  const btCollisionObjectWrapper* obj0Wrap = isSwapped ? m_body1Wrap : m_body0Wrap;
195  const btCollisionObjectWrapper* obj1Wrap = isSwapped ? m_body0Wrap : m_body1Wrap;
196  (*gContactAddedCallback)(m_manifoldPtr->getContactPoint(insertIndex), obj0Wrap, newPt.m_partId0, newPt.m_index0, obj1Wrap, newPt.m_partId1, newPt.m_index1);
197  }
198 
199  if (gContactStartedCallback && isNewCollision)
200  {
202  }
203 }
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:1251
CalculateCombinedCallback gCalculateCombinedRestitutionCallback
#define btAssert(x)
Definition: btScalar.h:133
static btScalar calculateCombinedContactStiffness(const btCollisionObject *body0, const btCollisionObject *body1)
ManifoldContactPoint collects and maintains persistent contactpoints.
btScalar(* CalculateCombinedCallback)(const btCollisionObject *body0, const btCollisionObject *body1)
These callbacks are used to customize the algorith that combine restitution, friction, damping, Stiffness.
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
CalculateCombinedCallback gCalculateCombinedContactDampingCallback
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:215
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:80
bool(* ContactAddedCallback)(btManifoldPoint &cp, const btCollisionObjectWrapper *colObj0Wrap, int partId0, int index0, const btCollisionObjectWrapper *colObj1Wrap, int partId1, int index1)
btScalar m_combinedContactDamping1
btScalar getSpinningFriction() const
CalculateCombinedCallback gCalculateCombinedSpinningFrictionCallback
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
CalculateCombinedCallback gCalculateCombinedContactStiffnessCallback
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
CalculateCombinedCallback gCalculateCombinedFrictionCallback
CalculateCombinedCallback gCalculateCombinedRollingFrictionCallback
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:294
btScalar m_combinedSpinningFriction
int getCacheEntry(const btManifoldPoint &newPoint) const