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contact solve for newton

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This commit is contained in:
Xuchen Han
2019-08-28 10:01:14 -07:00
parent 5826492020
commit 7d1b93cc17
9 changed files with 63 additions and 38 deletions
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29
src/BulletSoftBody/btDeformableMultiBodyDynamicsWorld.cpp
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@@ -168,6 +168,7 @@ void btDeformableMultiBodyDynamicsWorld::integrateTransforms(btScalar timeStep)
}
node.m_x = node.m_x + timeStep * node.m_v;
node.m_q = node.m_x;
node.m_vn = node.m_v;
}
}
m_deformableBodySolver->revertVelocity();
@@ -175,11 +176,8 @@ void btDeformableMultiBodyDynamicsWorld::integrateTransforms(btScalar timeStep)
void btDeformableMultiBodyDynamicsWorld::solveConstraints(btScalar timeStep)
{
if (!m_implicit)
{
// save v_{n+1}^* velocity after explicit forces
m_deformableBodySolver->backupVelocity();
}
// save v_{n+1}^* velocity after explicit forces
m_deformableBodySolver->backupVelocity();
// set up constraints among multibodies and between multibodies and deformable bodies
setupConstraints();
@@ -187,11 +185,13 @@ void btDeformableMultiBodyDynamicsWorld::solveConstraints(btScalar timeStep)
if (m_implicit)
{
// revert to v_n after collisions are registered
m_deformableBodySolver->revertVelocity();
// todo @xuchenhan : think about whether contact solve should be done with v_n velocity or v_{n+1}^* velocity. It's using v_n for implicit and v_{n+1}^* for non-implicit now.
// at this point dv = v_{n+1} - v_{n+1}^*
// modify dv such that dv = v_{n+1} - v_n
// modify m_backupVelocity so that it stores v_n instead of v_{n+1}^* as needed by Newton
m_deformableBodySolver->backupVn();
}
// At this point, dv is golden for nodes in contact
// At this point, dv should be golden for nodes in contact
m_deformableBodySolver->solveDeformableConstraints(timeStep);
}
@@ -211,7 +211,6 @@ void btDeformableMultiBodyDynamicsWorld::setupConstraints()
// build islands
m_islandManager->buildIslands(getCollisionWorld()->getDispatcher(), getCollisionWorld());
// write the constraint information of each island to the callback, and also setup the constraints in solver
}
}
@@ -317,11 +316,11 @@ void btDeformableMultiBodyDynamicsWorld::reinitialize(btScalar timeStep)
m_internalTime += timeStep;
m_deformableBodySolver->setImplicit(m_implicit);
m_deformableBodySolver->reinitialize(m_softBodies, timeStep);
if (m_implicit)
{
// backup v_n velocity
m_deformableBodySolver->backupVelocity();
}
// if (m_implicit)
// {
// // todo: backup v_n velocity somewhere else
// m_deformableBodySolver->backupVelocity();
// }
btDispatcherInfo& dispatchInfo = btMultiBodyDynamicsWorld::getDispatchInfo();
dispatchInfo.m_timeStep = timeStep;
dispatchInfo.m_stepCount = 0;