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 {
100 }
101 
102 
103 void btManifoldResult::addContactPoint(const btVector3& normalOnBInWorld,const btVector3& pointInWorld,btScalar depth)
104 {
106  //order in manifold needs to match
107 
109 // if (depth > m_manifoldPtr->getContactProcessingThreshold())
110  return;
111 
112  bool isSwapped = m_manifoldPtr->getBody0() != m_body0Wrap->getCollisionObject();
113 
114  btVector3 pointA = pointInWorld + normalOnBInWorld * depth;
115 
116  btVector3 localA;
117  btVector3 localB;
118 
119  if (isSwapped)
120  {
122  localB = m_body0Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
123  } else
124  {
126  localB = m_body1Wrap->getCollisionObject()->getWorldTransform().invXform(pointInWorld);
127  }
128 
129  btManifoldPoint newPt(localA,localB,normalOnBInWorld,depth);
130  newPt.m_positionWorldOnA = pointA;
131  newPt.m_positionWorldOnB = pointInWorld;
132 
133  int insertIndex = m_manifoldPtr->getCacheEntry(newPt);
134 
139 
142  {
146  }
147 
149 
150 
151 
152  //BP mod, store contact triangles.
153  if (isSwapped)
154  {
155  newPt.m_partId0 = m_partId1;
156  newPt.m_partId1 = m_partId0;
157  newPt.m_index0 = m_index1;
158  newPt.m_index1 = m_index0;
159  } else
160  {
161  newPt.m_partId0 = m_partId0;
162  newPt.m_partId1 = m_partId1;
163  newPt.m_index0 = m_index0;
164  newPt.m_index1 = m_index1;
165  }
166  //printf("depth=%f\n",depth);
168  if (insertIndex >= 0)
169  {
170  //const btManifoldPoint& oldPoint = m_manifoldPtr->getContactPoint(insertIndex);
171  m_manifoldPtr->replaceContactPoint(newPt,insertIndex);
172  } else
173  {
174  insertIndex = m_manifoldPtr->addManifoldPoint(newPt);
175  }
176 
177  //User can override friction and/or restitution
178  if (gContactAddedCallback &&
179  //and if either of the two bodies requires custom material
182  {
183  //experimental feature info, for per-triangle material etc.
184  const btCollisionObjectWrapper* obj0Wrap = isSwapped? m_body1Wrap : m_body0Wrap;
185  const btCollisionObjectWrapper* obj1Wrap = isSwapped? m_body0Wrap : m_body1Wrap;
186  (*gContactAddedCallback)(m_manifoldPtr->getContactPoint(insertIndex),obj0Wrap,newPt.m_partId0,newPt.m_index0,obj1Wrap,newPt.m_partId1,newPt.m_index1);
187  }
188 
189 }
190 
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:1282
#define btAssert(x)
Definition: btScalar.h:114
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:279
btScalar m_combinedSpinningFriction
int getCacheEntry(const btManifoldPoint &newPoint) const