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/*
* Copyright (c) 2005 Erwin Coumans http://www.erwincoumans.com
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies.
* Erwin Coumans makes no representations about the suitability
* of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*/
#include "Point2PointConstraint.h"
#include "Dynamics/RigidBody.h"
#include "Dynamics/MassProps.h"
static RigidBody s_fixed(MassProps(0,SimdVector3(0.f,0.f,0.f)),0.f,0.f,1.f,1.f);
Point2PointConstraint::Point2PointConstraint():
m_rbA(s_fixed),m_rbB(s_fixed)
{
s_fixed.setMassProps(0.f,SimdVector3(0.f,0.f,0.f));
}
Point2PointConstraint::Point2PointConstraint(RigidBody& rbA,RigidBody& rbB, const SimdVector3& pivotInA,const SimdVector3& pivotInB)
:m_rbA(rbA),m_rbB(rbB),m_pivotInA(pivotInA),m_pivotInB(pivotInB)
{
}
Point2PointConstraint::Point2PointConstraint(RigidBody& rbA,const SimdVector3& pivotInA)
:m_rbA(rbA),m_rbB(s_fixed),m_pivotInA(pivotInA),m_pivotInB(rbA.getCenterOfMassTransform()(pivotInA))
{
s_fixed.setMassProps(0.f,SimdVector3(1e10f,1e10f,1e10f));
}
void Point2PointConstraint::BuildJacobian()
{
SimdVector3 normal(0,0,0);
for (int i=0;i<3;i++)
{
normal[i] = 1;
new (&m_jac[i]) JacobianEntry(
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
m_rbA.getCenterOfMassTransform()*m_pivotInA - m_rbA.getCenterOfMassPosition(),
m_rbB.getCenterOfMassTransform()*m_pivotInB - m_rbB.getCenterOfMassPosition(),
normal,
m_rbA.getInvInertiaDiagLocal(),
m_rbA.getInvMass(),
m_rbB.getInvInertiaDiagLocal(),
m_rbB.getInvMass());
normal[i] = 0;
}
}
void Point2PointConstraint::SolveConstraint(SimdScalar timeStep)
{
SimdVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_pivotInA;
SimdVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_pivotInB;
SimdVector3 normal(0,0,0);
SimdScalar tau = 0.3f;
SimdScalar damping = 1.f;
// SimdVector3 angvelA = m_rbA.getCenterOfMassTransform().getBasis().transpose() * m_rbA.getAngularVelocity();
// SimdVector3 angvelB = m_rbB.getCenterOfMassTransform().getBasis().transpose() * m_rbB.getAngularVelocity();
for (int i=0;i<3;i++)
{
normal[i] = 1;
SimdScalar jacDiagABInv = 1.f / m_jac[i].getDiagonal();
SimdVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
SimdVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
//this jacobian entry could be re-used for all iterations
SimdVector3 vel1 = m_rbA.getVelocityInLocalPoint(rel_pos1);
SimdVector3 vel2 = m_rbB.getVelocityInLocalPoint(rel_pos2);
SimdVector3 vel = vel1 - vel2;
SimdScalar rel_vel;
rel_vel = normal.dot(vel);
/*
//velocity error (first order error)
SimdScalar rel_vel = m_jac[i].getRelativeVelocity(m_rbA.getLinearVelocity(),angvelA,
m_rbB.getLinearVelocity(),angvelB);
*/
//positional error (zeroth order error)
SimdScalar depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
SimdScalar impulse = depth*tau/timeStep * jacDiagABInv - damping * rel_vel * jacDiagABInv * damping;
SimdVector3 impulse_vector = normal * impulse;
m_rbA.applyImpulse(impulse_vector, pivotAInW - m_rbA.getCenterOfMassPosition());
m_rbB.applyImpulse(-impulse_vector, pivotBInW - m_rbB.getCenterOfMassPosition());
normal[i] = 0;
}
}
void Point2PointConstraint::UpdateRHS(SimdScalar timeStep)
{
}
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