Blender  V3.3
btContactConstraint.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 "btContactConstraint.h"
18 #include "LinearMath/btVector3.h"
19 #include "btJacobianEntry.h"
20 #include "btContactSolverInfo.h"
21 #include "LinearMath/btMinMax.h"
23 
26  m_contactManifold(*contactManifold)
27 {
28 }
29 
31 {
32 }
33 
35 {
36  m_contactManifold = *contactManifold;
37 }
38 
40 {
41 }
42 
44 {
45 }
46 
48 {
49 }
50 
51 #include "btContactConstraint.h"
53 #include "LinearMath/btVector3.h"
54 #include "btJacobianEntry.h"
55 #include "btContactSolverInfo.h"
56 #include "LinearMath/btMinMax.h"
58 
59 //response between two dynamic objects without friction and no restitution, assuming 0 penetration depth
61  btRigidBody* body1,
62  btCollisionObject* colObj2,
63  const btVector3& contactPositionWorld,
64  const btVector3& contactNormalOnB,
65  const btContactSolverInfo& solverInfo,
67 {
68  btRigidBody* body2 = btRigidBody::upcast(colObj2);
69 
70  const btVector3& normal = contactNormalOnB;
71 
72  btVector3 rel_pos1 = contactPositionWorld - body1->getWorldTransform().getOrigin();
73  btVector3 rel_pos2 = contactPositionWorld - colObj2->getWorldTransform().getOrigin();
74 
75  btVector3 vel1 = body1->getVelocityInLocalPoint(rel_pos1);
76  btVector3 vel2 = body2 ? body2->getVelocityInLocalPoint(rel_pos2) : btVector3(0, 0, 0);
77  btVector3 vel = vel1 - vel2;
78  btScalar rel_vel;
79  rel_vel = normal.dot(vel);
80 
81  btScalar combinedRestitution = 0.f;
82  btScalar restitution = combinedRestitution * -rel_vel;
83 
84  btScalar positionalError = solverInfo.m_erp * -distance / solverInfo.m_timeStep;
85  btScalar velocityError = -(1.0f + restitution) * rel_vel; // * damping;
86  btScalar denom0 = body1->computeImpulseDenominator(contactPositionWorld, normal);
87  btScalar denom1 = body2 ? body2->computeImpulseDenominator(contactPositionWorld, normal) : 0.f;
88  btScalar relaxation = 1.f;
89  btScalar jacDiagABInv = relaxation / (denom0 + denom1);
90 
91  btScalar penetrationImpulse = positionalError * jacDiagABInv;
92  btScalar velocityImpulse = velocityError * jacDiagABInv;
93 
94  btScalar normalImpulse = penetrationImpulse + velocityImpulse;
95  normalImpulse = 0.f > normalImpulse ? 0.f : normalImpulse;
96 
97  body1->applyImpulse(normal * (normalImpulse), rel_pos1);
98  if (body2)
99  body2->applyImpulse(-normal * (normalImpulse), rel_pos2);
100 
101  return normalImpulse;
102 }
103 
104 //bilateral constraint between two dynamic objects
106  btRigidBody& body2, const btVector3& pos2,
107  btScalar distance, const btVector3& normal, btScalar& impulse, btScalar timeStep)
108 {
109  (void)timeStep;
110  (void)distance;
111 
112  btScalar normalLenSqr = normal.length2();
113  btAssert(btFabs(normalLenSqr) < btScalar(1.1));
114  if (normalLenSqr > btScalar(1.1))
115  {
116  impulse = btScalar(0.);
117  return;
118  }
119  btVector3 rel_pos1 = pos1 - body1.getCenterOfMassPosition();
120  btVector3 rel_pos2 = pos2 - body2.getCenterOfMassPosition();
121  //this jacobian entry could be re-used for all iterations
122 
123  btVector3 vel1 = body1.getVelocityInLocalPoint(rel_pos1);
124  btVector3 vel2 = body2.getVelocityInLocalPoint(rel_pos2);
125  btVector3 vel = vel1 - vel2;
126 
127  btJacobianEntry jac(body1.getCenterOfMassTransform().getBasis().transpose(),
128  body2.getCenterOfMassTransform().getBasis().transpose(),
129  rel_pos1, rel_pos2, normal, body1.getInvInertiaDiagLocal(), body1.getInvMass(),
130  body2.getInvInertiaDiagLocal(), body2.getInvMass());
131 
132  btScalar jacDiagAB = jac.getDiagonal();
133  btScalar jacDiagABInv = btScalar(1.) / jacDiagAB;
134 
135  btScalar rel_vel = jac.getRelativeVelocity(
136  body1.getLinearVelocity(),
137  body1.getCenterOfMassTransform().getBasis().transpose() * body1.getAngularVelocity(),
138  body2.getLinearVelocity(),
139  body2.getCenterOfMassTransform().getBasis().transpose() * body2.getAngularVelocity());
140 
141  rel_vel = normal.dot(vel);
142 
143  //todo: move this into proper structure
144  btScalar contactDamping = btScalar(0.2);
145 
146 #ifdef ONLY_USE_LINEAR_MASS
147  btScalar massTerm = btScalar(1.) / (body1.getInvMass() + body2.getInvMass());
148  impulse = -contactDamping * rel_vel * massTerm;
149 #else
150  btScalar velocityImpulse = -contactDamping * rel_vel * jacDiagABInv;
151  impulse = velocityImpulse;
152 #endif
153 }
btCollisionObject
virtual void getInfo2(btConstraintInfo2 *info)
virtual void buildJacobian()
internal method used by the constraint solver, don't use them directly
virtual void getInfo1(btConstraintInfo1 *info)
void resolveSingleBilateral(btRigidBody &body1, const btVector3 &pos1, btRigidBody &body2, const btVector3 &pos2, btScalar distance, const btVector3 &normal, btScalar &impulse, btScalar timeStep)
resolveSingleBilateral is an obsolete methods used for vehicle friction between two dynamic objects
btScalar resolveSingleCollision(btRigidBody *body1, btCollisionObject *colObj2, const btVector3 &contactPositionWorld, const btVector3 &contactNormalOnB, const btContactSolverInfo &solverInfo, btScalar distance)
virtual ~btContactConstraint()
btContactConstraint(btPersistentManifold *contactManifold, btRigidBody &rbA, btRigidBody &rbB)
void setContactManifold(btPersistentManifold *contactManifold)
btFixedConstraint btRigidBody & rbB
btJacobianEntry
btPersistentManifold()
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
SIMD_FORCE_INLINE btScalar btFabs(btScalar x)
Definition: btScalar.h:497
#define btAssert(x)
Definition: btScalar.h:295
btTypedConstraint(btTypedConstraintType type, btRigidBody &rbA)
@ CONTACT_CONSTRAINT_TYPE
btVector3
btVector3 can be used to represent 3D points and vectors. It has an un-used w component to suit 16-by...
Definition: btVector3.h:82
const btVector3 & getAngularVelocity() const
Definition: btRigidBody.h:437
btVector3 getVelocityInLocalPoint(const btVector3 &rel_pos) const
Definition: btRigidBody.h:460
btScalar getInvMass() const
Definition: btRigidBody.h:263
static const btRigidBody * upcast(const btCollisionObject *colObj)
Definition: btRigidBody.h:189
void applyImpulse(const btVector3 &impulse, const btVector3 &rel_pos)
Definition: btRigidBody.h:335
SIMD_FORCE_INLINE btScalar computeImpulseDenominator(const btVector3 &pos, const btVector3 &normal) const
Definition: btRigidBody.h:482
const btTransform & getCenterOfMassTransform() const
Definition: btRigidBody.h:429
const btVector3 & getLinearVelocity() const
Definition: btRigidBody.h:433
const btVector3 & getCenterOfMassPosition() const
Definition: btRigidBody.h:423
const btVector3 & getInvInertiaDiagLocal() const
Definition: btRigidBody.h:289
SyclQueue void void size_t num_bytes void
IconTextureDrawCall normal
T distance(const T &a, const T &b)