Scarfski/bullet3
1
0
Fork 0
mirror of https://github.com/bulletphysics/bullet3.git synced 2026-09-26 20:16:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

add support for initial rotation

Browse Source
This commit is contained in:
jingyuc
2021-09-02 21:32:16 -04:00
parent 93e00054e3
commit e70fc6453b
4 changed files with 51 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
examples/ReducedDeformableDemo/BasicTest.cpp
View File

@@ -198,7 +198,7 @@ void BasicTest::initPhysics()
m_broadphase = new btDbvtBroadphase();
btReducedSoftBodySolver* reducedSoftBodySolver = new btReducedSoftBodySolver();
btVector3 gravity = btVector3(0, -10, 0);
btVector3 gravity = btVector3(0, 0, 0);
reducedSoftBodySolver->setGravity(gravity);
btDeformableMultiBodyConstraintSolver* sol = new btDeformableMultiBodyConstraintSolver();
@@ -220,17 +220,22 @@ void BasicTest::initPhysics()
getDeformableDynamicsWorld()->addSoftBody(rsb);
rsb->getCollisionShape()->setMargin(0.1);
// rsb->scale(btVector3(1, 1, 1)); //TODO: add back scale
rsb->translate(btVector3(0, 4, 0));
btTransform init_transform;
init_transform.setIdentity();
init_transform.setOrigin(btVector3(0, 4, 0));
init_transform.setRotation(btQuaternion(btVector3(0, 1, 0), SIMD_PI / 2.0));
rsb->transform(init_transform);
// rsb->setTotalMass(0.5);
rsb->setStiffnessScale(100);
rsb->setDamping(damping_alpha, damping_beta);
// set fixed nodes
rsb->setFixedNodes(0);
rsb->setFixedNodes(1);
rsb->setFixedNodes(2);
rsb->setFixedNodes(3);
// rsb->setFixedNodes(0);
// rsb->setFixedNodes(1);
// rsb->setFixedNodes(2);
// rsb->setFixedNodes(3);
rsb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
rsb->m_cfg.kCHR = 1; // collision hardness with rigid body

59
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.cpp
View File

@@ -82,31 +82,12 @@ void btReducedSoftBody::setInertiaProps(const btVector3& inertia)
inertia.y() != btScalar(0.0) ? btScalar(1.0) / inertia.y() : btScalar(0.0),
inertia.z() != btScalar(0.0) ? btScalar(1.0) / inertia.z() : btScalar(0.0));
// // CoM
// btVector3 x_com(0,0,0);
// for (int i = 0; i < m_nFull; ++i)
// {
// x_com += m_nodalMass[i] * m_nodes[i].m_x;
// }
// x_com /= m_mass;
// btMatrix3x3 inertia_temp;
// inertia_temp.setZero();
// for (int i = 0; i < m_nFull; ++i)
// {
// btVector3 ri = m_nodes[i].m_x - x_com;
// for (int a = 0; a < 3; ++a)
// {
// for (int b = 0; b < 3; ++b)
// {
// inertia_temp[a][b] += m_nodalMass[i] * ri[a] * ri[b];
// }
// }
// }
// m_invInertiaLocal = inertia_temp.inverse();
// update world inertia tensor
btMatrix3x3 rotation;
rotation.setIdentity();
updateInitialInertiaTensor(rotation);
updateInertiaTensor();
m_interpolateInvInertiaTensorWorld = m_invInertiaTensorWorld;
}
@@ -363,28 +344,21 @@ void btReducedSoftBody::proceedToTransform(btScalar dt, bool end_of_time_step)
m_invInertiaTensorWorld = m_interpolateInvInertiaTensorWorld;
}
void btReducedSoftBody::translate(const btVector3& trs)
void btReducedSoftBody::transform(const btTransform& trs)
{
// translate mesh
btSoftBody::translate(trs);
btSoftBody::transform(trs);
updateRestNodalPositions();
// update rigid frame
m_rigidTransformWorld.setOrigin(trs);
// update rigid frame (No need to update the rotation. Nodes have already been updated.)
m_rigidTransformWorld.setOrigin(trs.getOrigin());
m_interpolationWorldTransform = m_rigidTransformWorld;
m_initialOrigin = m_rigidTransformWorld.getOrigin();
updateInertiaTensor();
}
void btReducedSoftBody::rotate(const btQuaternion& rot)
{
// translate mesh
btSoftBody::rotate(rot);
updateRestNodalPositions();
// update rigid frame
m_rigidTransformWorld.setRotation(rot);
m_interpolationWorldTransform = m_rigidTransformWorld;
updateLocalMomentArm();
// update inertia tensor
updateInitialInertiaTensor(trs.getBasis());
updateInertiaTensor();
}
@@ -393,12 +367,19 @@ void btReducedSoftBody::updateRestNodalPositions()
// update reset nodal position
m_x0.resize(m_nFull);
for (int i = 0; i < m_nFull; ++i)
m_x0[i] = m_nodes[i].m_x;
{
m_x0[i] = m_nodes[i].m_x;
}
}
void btReducedSoftBody::updateInitialInertiaTensor(const btMatrix3x3& rotation)
{
m_invInertiaTensorWorldInitial = rotation.scaled(m_invInertiaLocal) * rotation.transpose();
}
void btReducedSoftBody::updateInertiaTensor()
{
m_invInertiaTensorWorld = m_rigidTransformWorld.getBasis().scaled(m_invInertiaLocal) * m_rigidTransformWorld.getBasis().transpose();
m_invInertiaTensorWorld = m_rigidTransformWorld.getBasis() * m_invInertiaTensorWorldInitial * m_rigidTransformWorld.getBasis().transpose();
}
void btReducedSoftBody::applyDamping(btScalar timeStep)

19
src/BulletSoftBody/BulletReducedSoftBody/btReducedSoftBody.h
View File

@@ -48,6 +48,7 @@ class btReducedSoftBody : public btSoftBody
btVector3 m_angularFactor;
btVector3 m_invInertiaLocal;
btTransform m_rigidTransformWorld;
btMatrix3x3 m_invInertiaTensorWorldInitial;
btMatrix3x3 m_invInertiaTensorWorld;
btMatrix3x3 m_interpolateInvInertiaTensorWorld;
btVector3 m_initialOrigin; // initial center of mass (original of the m_rigidTransformWorld)
@@ -121,12 +122,24 @@ class btReducedSoftBody : public btSoftBody
//
// various internal updates
//
virtual void translate(const btVector3& trs);
virtual void rotate(const btQuaternion& rot);
virtual void transform(const btTransform& trs);
virtual void translate(const btVector3& trs)
{
btAssert(false); // use transform().
}
virtual void rotate(const btQuaternion& rot)
{
btAssert(false); // use transform().
}
virtual void scale(const btVector3& scl)
{
btAssert(false); // scale is NOT supported in the reduced deformable body
}
void updateRestNodalPositions();
void updateInitialInertiaTensor(const btMatrix3x3& rotation);
void updateInertiaTensor();
void updateLocalMomentArm();

6
src/BulletSoftBody/btSoftBody.h
View File

@@ -1006,13 +1006,13 @@ public:
/* Transform to given pose */
void transformTo(const btTransform& trs);
/* Transform */
void transform(const btTransform& trs);
virtual void transform(const btTransform& trs);
/* Translate */
virtual void translate(const btVector3& trs);
/* Rotate */
void rotate(const btQuaternion& rot);
virtual void rotate(const btQuaternion& rot);
/* Scale */
void scale(const btVector3& scl);
virtual void scale(const btVector3& scl);
/* Get link resting lengths scale */
btScalar getRestLengthScale();
/* Scale resting length of all springs */