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"
18 #include "BulletCollision/NarrowPhaseCollision/btPersistentManifold.h"
19 #include "BulletCollision/CollisionDispatch/btCollisionObject.h"
20
21
22 ///This is to allow MaterialCombiner/Custom Friction/Restitution values
23 ContactAddedCallback gContactAddedCallback=0;
24
25 ///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= btCollisionObject::customMaterialCallback;
calculateCombinedFriction(const btCollisionObject * body0,const btCollisionObject * body1)26 inline btScalar calculateCombinedFriction(const btCollisionObject* body0,const btCollisionObject* body1)
27 {
28 btScalar friction = body0->getFriction() * body1->getFriction();
29
30 const btScalar MAX_FRICTION = btScalar(10.);
31 if (friction < -MAX_FRICTION)
32 friction = -MAX_FRICTION;
33 if (friction > MAX_FRICTION)
34 friction = MAX_FRICTION;
35 return friction;
36
37 }
38
calculateCombinedRestitution(const btCollisionObject * body0,const btCollisionObject * body1)39 inline btScalar calculateCombinedRestitution(const btCollisionObject* body0,const btCollisionObject* body1)
40 {
41 return body0->getRestitution() * body1->getRestitution();
42 }
43
44
45
btManifoldResult(btCollisionObject * body0,btCollisionObject * body1)46 btManifoldResult::btManifoldResult(btCollisionObject* body0,btCollisionObject* body1)
47 :m_manifoldPtr(0),
48 m_body0(body0),
49 m_body1(body1)
50 #ifdef DEBUG_PART_INDEX
51 ,m_partId0(-1),
52 m_partId1(-1),
53 m_index0(-1),
54 m_index1(-1)
55 #endif //DEBUG_PART_INDEX
56 {
57 m_rootTransA = body0->getWorldTransform();
58 m_rootTransB = body1->getWorldTransform();
59 }
60
61
addContactPoint(const btVector3 & normalOnBInWorld,const btVector3 & pointInWorld,btScalar depth)62 void btManifoldResult::addContactPoint(const btVector3& normalOnBInWorld,const btVector3& pointInWorld,btScalar depth)
63 {
64 btAssert(m_manifoldPtr);
65 //order in manifold needs to match
66
67 if (depth > m_manifoldPtr->getContactBreakingThreshold())
68 return;
69
70 bool isSwapped = m_manifoldPtr->getBody0() != m_body0;
71
72 btVector3 pointA = pointInWorld + normalOnBInWorld * depth;
73
74 btVector3 localA;
75 btVector3 localB;
76
77 if (isSwapped)
78 {
79 localA = m_rootTransB.invXform(pointA );
80 localB = m_rootTransA.invXform(pointInWorld);
81 } else
82 {
83 localA = m_rootTransA.invXform(pointA );
84 localB = m_rootTransB.invXform(pointInWorld);
85 }
86
87 btManifoldPoint newPt(localA,localB,normalOnBInWorld,depth);
88 newPt.m_positionWorldOnA = pointA;
89 newPt.m_positionWorldOnB = pointInWorld;
90
91 int insertIndex = m_manifoldPtr->getCacheEntry(newPt);
92
93 newPt.m_combinedFriction = calculateCombinedFriction(m_body0,m_body1);
94 newPt.m_combinedRestitution = calculateCombinedRestitution(m_body0,m_body1);
95
96 //BP mod, store contact triangles.
97 if (isSwapped)
98 {
99 newPt.m_partId0 = m_partId1;
100 newPt.m_partId1 = m_partId0;
101 newPt.m_index0 = m_index1;
102 newPt.m_index1 = m_index0;
103 } else
104 {
105 newPt.m_partId0 = m_partId0;
106 newPt.m_partId1 = m_partId1;
107 newPt.m_index0 = m_index0;
108 newPt.m_index1 = m_index1;
109 }
110 //printf("depth=%f\n",depth);
111 ///@todo, check this for any side effects
112 if (insertIndex >= 0)
113 {
114 //const btManifoldPoint& oldPoint = m_manifoldPtr->getContactPoint(insertIndex);
115 m_manifoldPtr->replaceContactPoint(newPt,insertIndex);
116 } else
117 {
118 insertIndex = m_manifoldPtr->addManifoldPoint(newPt);
119 }
120
121 //User can override friction and/or restitution
122 if (gContactAddedCallback &&
123 //and if either of the two bodies requires custom material
124 ((m_body0->getCollisionFlags() & btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK) ||
125 (m_body1->getCollisionFlags() & btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK)))
126 {
127 //experimental feature info, for per-triangle material etc.
128 btCollisionObject* obj0 = isSwapped? m_body1 : m_body0;
129 btCollisionObject* obj1 = isSwapped? m_body0 : m_body1;
130 (*gContactAddedCallback)(m_manifoldPtr->getContactPoint(insertIndex),obj0,newPt.m_partId0,newPt.m_index0,obj1,newPt.m_partId1,newPt.m_index1);
131 }
132
133 }
134
135