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fixed constraints wip

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This commit is contained in:
jingyuc
2021-07-28 16:36:15 -04:00
parent 549b57df77
commit c6c7533167
4 changed files with 60 additions and 24 deletions
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3
examples/ReducedDeformableDemo/BasicTest.cpp
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@@ -133,7 +133,7 @@ void BasicTest::initPhysics()
m_broadphase = new btDbvtBroadphase();
btReducedSoftBodySolver* reducedSoftBodySolver = new btReducedSoftBodySolver();
reducedSoftBodySolver->setDamping(damping_alpha, damping_beta);
btVector3 gravity = btVector3(0, 0, 0);
btVector3 gravity = btVector3(0, -9.8, 0);
reducedSoftBodySolver->setGravity(gravity);
btDeformableMultiBodyConstraintSolver* sol = new btDeformableMultiBodyConstraintSolver();
@@ -159,6 +159,7 @@ void BasicTest::initPhysics()
// rsb->translate(btVector3(0, 2, 0)); //TODO: add back translate and scale
// rsb->setTotalMass(0.5);
rsb->setStiffnessScale(1);
rsb->setFixedNodes();
rsb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
rsb->m_cfg.kCHR = 1; // collision hardness with rigid body
rsb->m_cfg.kDF = 0;

26
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.cpp
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@@ -83,6 +83,15 @@ void btReducedSoftBody::setMassScale(const btScalar rho)
m_rhoScale = rho;
}
void btReducedSoftBody::setFixedNodes()
{
for (int i = 0; i < m_nFull; ++i)
{
if (abs(m_nodes[i].m_x[2] - (-2)) < 1e-3)
m_fixedNodes.push_back(i);
}
}
void btReducedSoftBody::predictIntegratedTransform(btScalar timeStep, btTransform& predictedTransform)
{
btTransformUtil::integrateTransform(m_worldTransform, m_linearVelocity, m_angularVelocity, timeStep, predictedTransform);
@@ -221,7 +230,14 @@ void btReducedSoftBody::applyFullSpaceImpulse(const btVector3& target_vel, int n
void btReducedSoftBody::applyRigidGravity(const btVector3& gravity, btScalar dt)
{
// update rigid frame velocity
m_linearVelocity += dt * gravity;
// update nodal velocity
for (int i = 0; i < m_nFull; ++i)
{
m_nodes[i].m_v = m_nodes[i].m_v + dt * gravity;
}
}
void btReducedSoftBody::applyReducedInternalForce(tDenseArray& reduced_force, const btScalar damping_alpha, const btScalar damping_beta)
@@ -230,4 +246,14 @@ void btReducedSoftBody::applyReducedInternalForce(tDenseArray& reduced_force, co
{
reduced_force[r] += m_ksScale * m_Kr[r] * (m_reducedDofs[r] + damping_beta * m_reducedVelocity[r]);
}
}
void btReducedSoftBody::applyFixedContraints(btScalar dt, tDenseArray& reduced_force)
{
for (int n = 0; n < m_fixedNodes.size(); ++n)
{
// std::cout << reduced_force[0] << "\t" << reduced_force[1] << "\n";
applyFullSpaceImpulse(btVector3(0, 0, 0), m_fixedNodes[n], dt, reduced_force);
// std::cout << reduced_force[0] << "\t" << reduced_force[1] << "\n";
}
}

6
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.h
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@@ -54,6 +54,7 @@ class btReducedSoftBody : public btSoftBody
// full space
TVStack m_x0; // Rest position
tDenseArray m_nodalMass; // Mass on each node
btAlignedObjectArray<int> m_fixedNodes; // index of the fixed nodes
//
// Api
@@ -76,6 +77,8 @@ class btReducedSoftBody : public btSoftBody
void setMassScale(const btScalar rho);
void setFixedNodes();
virtual void translate(const btVector3& trs);
void updateRestNodalPositions();
@@ -107,6 +110,9 @@ class btReducedSoftBody : public btSoftBody
// apply impulse to nodes in the full space
void applyFullSpaceImpulse(const btVector3& target_vel, int n_node, btScalar dt, tDenseArray& reduced_force);
// apply fixed contraints to the nodes
void applyFixedContraints(btScalar dt, tDenseArray& reduced_force);
// apply gravity to the rigid frame
void applyRigidGravity(const btVector3& gravity, btScalar dt);

49
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBodySolver.cpp
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@@ -40,29 +40,32 @@ void btReducedSoftBodySolver::applyForce()
// apply impulses to reduced deformable objects
static btScalar sim_time = 0;
static int apply_impulse = 0;
if (rsb->m_reducedModel && apply_impulse < 4)
{
if (sim_time > 1 && apply_impulse == 0)
{
rsb->applyFullSpaceImpulse(btVector3(0, 1, 0), 0, 2.0 * m_dt, reduced_force);
apply_impulse++;
}
if (sim_time > 2 && apply_impulse == 1)
{
rsb->applyFullSpaceImpulse(btVector3(0, -1.2, 0), 0, m_dt, reduced_force);
apply_impulse++;
}
if (sim_time > 3 && apply_impulse == 2)
{
rsb->applyFullSpaceImpulse(btVector3(1.1, 0, 0), 0, m_dt, reduced_force);
apply_impulse++;
}
if (sim_time > 4 && apply_impulse == 3)
{
rsb->applyFullSpaceImpulse(btVector3(-1, 0, 0), 0, 2.0 * m_dt, reduced_force);
apply_impulse++;
}
}
// if (rsb->m_reducedModel && apply_impulse < 4)
// {
// if (sim_time > 1 && apply_impulse == 0)
// {
// rsb->applyFullSpaceImpulse(btVector3(0, 1, 0), 0, 2.0 * m_dt, reduced_force);
// apply_impulse++;
// }
// if (sim_time > 2 && apply_impulse == 1)
// {
// rsb->applyFullSpaceImpulse(btVector3(0, -1.2, 0), 0, m_dt, reduced_force);
// apply_impulse++;
// }
// if (sim_time > 3 && apply_impulse == 2)
// {
// rsb->applyFullSpaceImpulse(btVector3(1.1, 0, 0), 0, m_dt, reduced_force);
// apply_impulse++;
// }
// if (sim_time > 4 && apply_impulse == 3)
// {
// rsb->applyFullSpaceImpulse(btVector3(-1, 0, 0), 0, 2.0 * m_dt, reduced_force);
// apply_impulse++;
// }
// }
// apply fixed contraints
rsb->applyFixedContraints(m_dt, reduced_force);
// update reduced velocity
for (int r = 0; r < rsb->m_reducedDofs.size(); ++r)