1 /*
2 Written by Xuchen Han <xuchenhan2015@u.northwestern.edu>
3
4 Bullet Continuous Collision Detection and Physics Library
5 Copyright (c) 2019 Google Inc. http://bulletphysics.org
6 This software is provided 'as-is', without any express or implied warranty.
7 In no event will the authors be held liable for any damages arising from the use of this software.
8 Permission is granted to anyone to use this software for any purpose,
9 including commercial applications, and to alter it and redistribute it freely,
10 subject to the following restrictions:
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 "btDeformableMultiBodyConstraintSolver.h"
17 #include <iostream>
18 // override the iterations method to include deformable/multibody contact
solveDeformableGroupIterations(btCollisionObject ** bodies,int numBodies,btCollisionObject ** deformableBodies,int numDeformableBodies,btPersistentManifold ** manifoldPtr,int numManifolds,btTypedConstraint ** constraints,int numConstraints,const btContactSolverInfo & infoGlobal,btIDebugDraw * debugDrawer)19 btScalar btDeformableMultiBodyConstraintSolver::solveDeformableGroupIterations(btCollisionObject** bodies, int numBodies, btCollisionObject** deformableBodies, int numDeformableBodies, btPersistentManifold** manifoldPtr, int numManifolds, btTypedConstraint** constraints, int numConstraints, const btContactSolverInfo& infoGlobal, btIDebugDraw* debugDrawer)
20 {
21 {
22 ///this is a special step to resolve penetrations (just for contacts)
23 solveGroupCacheFriendlySplitImpulseIterations(bodies, numBodies, deformableBodies, numDeformableBodies, manifoldPtr, numManifolds, constraints, numConstraints, infoGlobal, debugDrawer);
24
25 int maxIterations = m_maxOverrideNumSolverIterations > infoGlobal.m_numIterations ? m_maxOverrideNumSolverIterations : infoGlobal.m_numIterations;
26 for (int iteration = 0; iteration < maxIterations; iteration++)
27 {
28 // rigid bodies are solved using solver body velocity, but rigid/deformable contact directly uses the velocity of the actual rigid body. So we have to do the following: Solve one iteration of the rigid/rigid contact, get the updated velocity in the solver body and update the velocity of the underlying rigid body. Then solve the rigid/deformable contact. Finally, grab the (once again) updated rigid velocity and update the velocity of the wrapping solver body
29
30 // solve rigid/rigid in solver body
31 m_leastSquaresResidual = solveSingleIteration(iteration, bodies, numBodies, manifoldPtr, numManifolds, constraints, numConstraints, infoGlobal, debugDrawer);
32 // solver body velocity -> rigid body velocity
33 solverBodyWriteBack(infoGlobal);
34 btScalar deformableResidual = m_deformableSolver->solveContactConstraints(deformableBodies, numDeformableBodies, infoGlobal);
35 // update rigid body velocity in rigid/deformable contact
36 m_leastSquaresResidual = btMax(m_leastSquaresResidual, deformableResidual);
37 // solver body velocity <- rigid body velocity
38 writeToSolverBody(bodies, numBodies, infoGlobal);
39
40 if (m_leastSquaresResidual <= infoGlobal.m_leastSquaresResidualThreshold || (iteration >= (maxIterations - 1)))
41 {
42 #ifdef VERBOSE_RESIDUAL_PRINTF
43 if (iteration >= (maxIterations - 1))
44 printf("residual = %f at iteration #%d\n", m_leastSquaresResidual, iteration);
45 #endif
46 m_analyticsData.m_numSolverCalls++;
47 m_analyticsData.m_numIterationsUsed = iteration + 1;
48 m_analyticsData.m_islandId = -2;
49 if (numBodies > 0)
50 m_analyticsData.m_islandId = bodies[0]->getCompanionId();
51 m_analyticsData.m_numBodies = numBodies;
52 m_analyticsData.m_numContactManifolds = numManifolds;
53 m_analyticsData.m_remainingLeastSquaresResidual = m_leastSquaresResidual;
54 break;
55 }
56 }
57 }
58 return 0.f;
59 }
60
solveDeformableBodyGroup(btCollisionObject ** bodies,int numBodies,btCollisionObject ** deformableBodies,int numDeformableBodies,btPersistentManifold ** manifold,int numManifolds,btTypedConstraint ** constraints,int numConstraints,btMultiBodyConstraint ** multiBodyConstraints,int numMultiBodyConstraints,const btContactSolverInfo & info,btIDebugDraw * debugDrawer,btDispatcher * dispatcher)61 void btDeformableMultiBodyConstraintSolver::solveDeformableBodyGroup(btCollisionObject** bodies, int numBodies, btCollisionObject** deformableBodies, int numDeformableBodies, btPersistentManifold** manifold, int numManifolds, btTypedConstraint** constraints, int numConstraints, btMultiBodyConstraint** multiBodyConstraints, int numMultiBodyConstraints, const btContactSolverInfo& info, btIDebugDraw* debugDrawer, btDispatcher* dispatcher)
62 {
63 m_tmpMultiBodyConstraints = multiBodyConstraints;
64 m_tmpNumMultiBodyConstraints = numMultiBodyConstraints;
65
66 // inherited from MultiBodyConstraintSolver
67 solveGroupCacheFriendlySetup(bodies, numBodies, manifold, numManifolds, constraints, numConstraints, info, debugDrawer);
68
69 // overriden
70 solveDeformableGroupIterations(bodies, numBodies, deformableBodies, numDeformableBodies, manifold, numManifolds, constraints, numConstraints, info, debugDrawer);
71
72 // inherited from MultiBodyConstraintSolver
73 solveGroupCacheFriendlyFinish(bodies, numBodies, info);
74
75 m_tmpMultiBodyConstraints = 0;
76 m_tmpNumMultiBodyConstraints = 0;
77 }
78
writeToSolverBody(btCollisionObject ** bodies,int numBodies,const btContactSolverInfo & infoGlobal)79 void btDeformableMultiBodyConstraintSolver::writeToSolverBody(btCollisionObject** bodies, int numBodies, const btContactSolverInfo& infoGlobal)
80 {
81 for (int i = 0; i < numBodies; i++)
82 {
83 int bodyId = getOrInitSolverBody(*bodies[i], infoGlobal.m_timeStep);
84
85 btRigidBody* body = btRigidBody::upcast(bodies[i]);
86 if (body && body->getInvMass())
87 {
88 btSolverBody& solverBody = m_tmpSolverBodyPool[bodyId];
89 solverBody.m_linearVelocity = body->getLinearVelocity() - solverBody.m_deltaLinearVelocity;
90 solverBody.m_angularVelocity = body->getAngularVelocity() - solverBody.m_deltaAngularVelocity;
91 }
92 }
93 }
94
solverBodyWriteBack(const btContactSolverInfo & infoGlobal)95 void btDeformableMultiBodyConstraintSolver::solverBodyWriteBack(const btContactSolverInfo& infoGlobal)
96 {
97 for (int i = 0; i < m_tmpSolverBodyPool.size(); i++)
98 {
99 btRigidBody* body = m_tmpSolverBodyPool[i].m_originalBody;
100 if (body)
101 {
102 m_tmpSolverBodyPool[i].m_originalBody->setLinearVelocity(m_tmpSolverBodyPool[i].m_linearVelocity + m_tmpSolverBodyPool[i].m_deltaLinearVelocity);
103 m_tmpSolverBodyPool[i].m_originalBody->setAngularVelocity(m_tmpSolverBodyPool[i].m_angularVelocity + m_tmpSolverBodyPool[i].m_deltaAngularVelocity);
104 }
105 }
106 }
107
solveGroupCacheFriendlySplitImpulseIterations(btCollisionObject ** bodies,int numBodies,btCollisionObject ** deformableBodies,int numDeformableBodies,btPersistentManifold ** manifoldPtr,int numManifolds,btTypedConstraint ** constraints,int numConstraints,const btContactSolverInfo & infoGlobal,btIDebugDraw * debugDrawer)108 void btDeformableMultiBodyConstraintSolver::solveGroupCacheFriendlySplitImpulseIterations(btCollisionObject** bodies, int numBodies, btCollisionObject** deformableBodies, int numDeformableBodies, btPersistentManifold** manifoldPtr, int numManifolds, btTypedConstraint** constraints, int numConstraints, const btContactSolverInfo& infoGlobal, btIDebugDraw* debugDrawer)
109 {
110 BT_PROFILE("solveGroupCacheFriendlySplitImpulseIterations");
111 int iteration;
112 if (infoGlobal.m_splitImpulse)
113 {
114 {
115 for (iteration = 0; iteration < infoGlobal.m_numIterations; iteration++)
116 {
117 btScalar leastSquaresResidual = 0.f;
118 {
119 int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
120 int j;
121 for (j = 0; j < numPoolConstraints; j++)
122 {
123 const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[j]];
124
125 btScalar residual = resolveSplitPenetrationImpulse(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA], m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB], solveManifold);
126 leastSquaresResidual = btMax(leastSquaresResidual, residual * residual);
127 }
128 // solve the position correction between deformable and rigid/multibody
129 // btScalar residual = m_deformableSolver->solveSplitImpulse(infoGlobal);
130 btScalar residual = m_deformableSolver->m_objective->m_projection.solveSplitImpulse(deformableBodies, numDeformableBodies, infoGlobal);
131 leastSquaresResidual = btMax(leastSquaresResidual, residual * residual);
132 }
133 if (leastSquaresResidual <= infoGlobal.m_leastSquaresResidualThreshold || iteration >= (infoGlobal.m_numIterations - 1))
134 {
135 #ifdef VERBOSE_RESIDUAL_PRINTF
136 if (iteration >= (infoGlobal.m_numIterations - 1))
137 printf("split impulse residual = %f at iteration #%d\n", leastSquaresResidual, iteration);
138 #endif
139 break;
140 }
141 }
142 }
143 }
144 }
145