Bullet Collision Detection & Physics Library
btContactConstraint.cpp
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1/*
2Bullet Continuous Collision Detection and Physics Library
3Copyright (c) 2003-2006 Erwin Coumans https://bulletphysics.org
4
5This software is provided 'as-is', without any express or implied warranty.
6In no event will the authors be held liable for any damages arising from the use of this software.
7Permission is granted to anyone to use this software for any purpose,
8including commercial applications, and to alter it and redistribute it freely,
9subject to the following restrictions:
10
111. 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.
122. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
133. This notice may not be removed or altered from any source distribution.
14*/
15
16#include "btContactConstraint.h"
19#include "btJacobianEntry.h"
20#include "btContactSolverInfo.h"
21#include "LinearMath/btMinMax.h"
23
26 m_contactManifold(*contactManifold)
27{
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50
51#include "btContactConstraint.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
66 btScalar distance)
67{
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);
79 rel_vel = normal.dot(vel);
80
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;
90
93
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
107 btScalar distance, const btVector3& normal, btScalar& impulse, btScalar timeStep)
108{
109 (void)timeStep;
110 (void)distance;
111
112 btScalar normalLenSqr = normal.length2();
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);
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();
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
145
146#ifdef ONLY_USE_LINEAR_MASS
147 btScalar massTerm = btScalar(1.) / (body1.getInvMass() + body2.getInvMass());
149#else
152#endif
153}
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)
const T & btMax(const T &a, const T &b)
Definition btMinMax.h:27
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition btScalar.h:314
btScalar btFabs(btScalar x)
Definition btScalar.h:497
#define btAssert(x)
Definition btScalar.h:153
@ CONTACT_CONSTRAINT_TYPE
btCollisionObject can be used to manage collision detection objects.
virtual void getInfo2(btConstraintInfo2 *info)
internal method used by the constraint solver, don't use them directly
virtual void buildJacobian()
obsolete methods
btPersistentManifold m_contactManifold
virtual void getInfo1(btConstraintInfo1 *info)
internal method used by the constraint solver, don't use them directly
btContactConstraint(btPersistentManifold *contactManifold, btRigidBody &rbA, btRigidBody &rbB)
void setContactManifold(btPersistentManifold *contactManifold)
Jacobian entry is an abstraction that allows to describe constraints it can be used in combination wi...
btPersistentManifold is a contact point cache, it stays persistent as long as objects are overlapping...
The btRigidBody is the main class for rigid body objects.
Definition btRigidBody.h:60
static const btRigidBody * upcast(const btCollisionObject *colObj)
to keep collision detection and dynamics separate we don't store a rigidbody pointer but a rigidbody ...
TypedConstraint is the baseclass for Bullet constraints and vehicles.
btVector3 can be used to represent 3D points and vectors.
Definition btVector3.h:82
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition btVector3.h:229
btScalar length2() const
Return the length of the vector squared.
Definition btVector3.h:251