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Merge pull request #3979 from johbrust/deformableForces

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Add deformable contact forces info
This commit is contained in:
erwincoumans
2021-11-13 22:32:43 -08:00
committed by GitHub
parent 691ad46baa 61d5bdb783
commit ccafe333d1
3 changed files with 97 additions and 39 deletions
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121
examples/SharedMemory/PhysicsServerCommandProcessor.cpp
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@@ -8073,21 +8073,26 @@ bool PhysicsServerCommandProcessor::processRequestDeformableContactpointHelper(c
{
return false;
}
int numSoftbodyContact = 0;
for (int i = deformWorld->getSoftBodyArray().size() - 1; i >= 0; i--)
{
numSoftbodyContact += deformWorld->getSoftBodyArray()[i]->m_faceRigidContacts.size();
}
int num_contact_points = m_data->m_cachedContactPoints.size();
m_data->m_cachedContactPoints.reserve(num_contact_points + numSoftbodyContact);
for (int i = deformWorld->getSoftBodyArray().size() - 1; i >= 0; i--)
{
btSoftBody* psb = deformWorld->getSoftBodyArray()[i];
btAlignedObjectArray<b3ContactPointData> distinctContactPoints;
btAlignedObjectArray<btSoftBody::Node*> nodesInContact;
for (int c = 0; c < psb->m_faceRigidContacts.size(); c++)
{
const btSoftBody::DeformableFaceRigidContact* contact = &psb->m_faceRigidContacts[i];
//convert rigidbody contact
const btSoftBody::DeformableFaceRigidContact* contact = &psb->m_faceRigidContacts[c];
// calculate normal and tangent impulse
btVector3 impulse = contact->m_cti.m_impulse;
btVector3 impulseNormal = impulse.dot(contact->m_cti.m_normal) * contact->m_cti.m_normal;
btVector3 impulseTangent = impulse - impulseNormal;
// get node in contact
int contactNodeIdx = contact->m_bary.maxAxis();
btSoftBody::Node* node = contact->m_face->m_n[contactNodeIdx];
// check if node is already in the list
int idx = nodesInContact.findLinearSearch2(node);
//apply the filter, if the user provides it
int linkIndexA = -1;
int linkIndexB = -1;
int objectIndexA = psb->getUserIndex2();
@@ -8104,8 +8109,6 @@ bool PhysicsServerCommandProcessor::processRequestDeformableContactpointHelper(c
linkIndexB = mblB->m_link;
objectIndexB = mblB->m_multiBody->getUserIndex2();
}
//apply the filter, if the user provides it
bool swap = false;
if (clientCmd.m_requestContactPointArguments.m_objectAIndexFilter >= 0)
{
@@ -8151,37 +8154,87 @@ bool PhysicsServerCommandProcessor::processRequestDeformableContactpointHelper(c
{
continue;
}
b3ContactPointData pt;
pt.m_bodyUniqueIdA = objectIndexA;
pt.m_bodyUniqueIdB = objectIndexB;
pt.m_contactDistance = contact->m_cti.m_offset;
pt.m_contactFlags = 0;
pt.m_linkIndexA = linkIndexA;
pt.m_linkIndexB = linkIndexB;
for (int j = 0; j < 3; j++)
if (idx < 0)
{
if (swap)
// add new node and contact point
nodesInContact.push_back(node);
b3ContactPointData pt;
pt.m_bodyUniqueIdA = objectIndexA;
pt.m_bodyUniqueIdB = objectIndexB;
pt.m_contactDistance = -contact->m_cti.m_offset;
pt.m_contactFlags = 0;
pt.m_linkIndexA = linkIndexA;
pt.m_linkIndexB = linkIndexB;
for (int j = 0; j < 3; j++)
{
pt.m_contactNormalOnBInWS[j] = -contact->m_cti.m_normal[j];
pt.m_positionOnAInWS[j] = contact->m_cti.m_normal[j];
pt.m_positionOnBInWS[j] = -contact->m_cti.m_normal[j];
if (swap)
{
pt.m_contactNormalOnBInWS[j] = -contact->m_cti.m_normal[j];
pt.m_positionOnAInWS[j] = node->m_x[j] - pt.m_contactDistance * pt.m_contactNormalOnBInWS[j]; // not really precise because of margins in btSoftBody.cpp:line 2912
// node is force application point, therefore node position is contact point (not contact->m_contactPoint, because not equal to node)
pt.m_positionOnBInWS[j] = node->m_x[j];
}
else
{
pt.m_contactNormalOnBInWS[j] = contact->m_cti.m_normal[j];
// node is force application point, therefore node position is contact point (not contact->m_contactPoint, because not equal to node)
pt.m_positionOnAInWS[j] = node->m_x[j];
pt.m_positionOnBInWS[j] = node->m_x[j] - pt.m_contactDistance * pt.m_contactNormalOnBInWS[j]; // not really precise because of margins in btSoftBody.cpp:line 2912
}
}
else
pt.m_normalForce = (impulseNormal / m_data->m_physicsDeltaTime).norm();
pt.m_linearFrictionForce1 = (impulseTangent.dot(contact->t1) * contact->t1 / m_data->m_physicsDeltaTime).norm();
pt.m_linearFrictionForce2 = (impulseTangent.dot(contact->t2) * contact->t2 / m_data->m_physicsDeltaTime).norm();
for (int j = 0; j < 3; j++)
{
pt.m_contactNormalOnBInWS[j] = contact->m_cti.m_normal[j];
pt.m_positionOnAInWS[j] = -contact->m_cti.m_normal[j];
pt.m_positionOnBInWS[j] = contact->m_cti.m_normal[j];
pt.m_linearFrictionDirection1[j] = contact->t1[j];
pt.m_linearFrictionDirection2[j] = contact->t2[j];
}
distinctContactPoints.push_back(pt);
}
pt.m_normalForce = 1;
pt.m_linearFrictionForce1 = 0;
pt.m_linearFrictionForce2 = 0;
for (int j = 0; j < 3; j++)
else
{
pt.m_linearFrictionDirection1[j] = 0;
pt.m_linearFrictionDirection2[j] = 0;
// add values to existing contact point
b3ContactPointData* pt = &distinctContactPoints[idx];
// current normal force of node
btVector3 normalForce = btVector3(btScalar(pt->m_contactNormalOnBInWS[0]),
btScalar(pt->m_contactNormalOnBInWS[1]),
btScalar(pt->m_contactNormalOnBInWS[2])) * pt->m_normalForce;
// add normal force of additional node contact
btScalar swapFactor = swap ? -1.0 : 1.0;
normalForce += swapFactor * contact->m_cti.m_normal * (impulseNormal / m_data->m_physicsDeltaTime).norm();
// get magnitude of normal force
pt->m_normalForce = normalForce.norm();
// get direction of normal force
if (!normalForce.fuzzyZero())
{
// normalize for unit vectors if above numerical threshold
normalForce.normalize();
for (int j = 0; j < 3; j++)
{
pt->m_contactNormalOnBInWS[j] = normalForce[j];
}
}
// add magnitudes of tangential forces in existing directions
btVector3 linearFrictionDirection1 = btVector3(btScalar(pt->m_linearFrictionDirection1[0]),
btScalar(pt->m_linearFrictionDirection1[1]),
btScalar(pt->m_linearFrictionDirection1[2]));
btVector3 linearFrictionDirection2 = btVector3(btScalar(pt->m_linearFrictionDirection2[0]),
btScalar(pt->m_linearFrictionDirection2[1]),
btScalar(pt->m_linearFrictionDirection2[2]));
pt->m_linearFrictionForce1 = (impulseTangent.dot(linearFrictionDirection1) * linearFrictionDirection1 / m_data->m_physicsDeltaTime).norm();
pt->m_linearFrictionForce2 = (impulseTangent.dot(linearFrictionDirection2) * linearFrictionDirection2 / m_data->m_physicsDeltaTime).norm();
}
m_data->m_cachedContactPoints.push_back(pt);
}
int num_contact_points = m_data->m_cachedContactPoints.size() + distinctContactPoints.size();
m_data->m_cachedContactPoints.reserve(num_contact_points);
// add points to contact points cache
for (int p = 0; p < distinctContactPoints.size(); p++)
{
m_data->m_cachedContactPoints.push_back(distinctContactPoints[p]);
}
}
#endif