blender/extern/bullet/BulletDynamics/ConstraintSolver/Point2PointConstraint.cpp
Erwin Coumans 6f3e593105 more graphics patches from Snailrose,
remove constraint fixed,
Bullet timestep now subdivides Blender game engine timestep, so it runs 60 hertz,
SphereShape reverted to old style, so no support for non-uniform scaled spheres for now,
2006-01-15 11:34:55 +00:00

116 lines
3.8 KiB
C++

/*
* Copyright (c) 2005 Erwin Coumans http://continuousphysics.com/Bullet/
*
* 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);
static int gConstraintId = 1;
Point2PointConstraint::Point2PointConstraint():
m_rbA(s_fixed),m_rbB(s_fixed)
{
m_constraintId = gConstraintId++;//just create some unique ID for now
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)
{
m_constraintId = gConstraintId++;//just create some unique ID for now
}
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));
m_constraintId = gConstraintId++;//just create some unique ID for now
}
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)
{
}