128 lines
3.2 KiB
C++
128 lines
3.2 KiB
C++
#include "pin_joint_sw.h"
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bool PinJointSW::setup(float p_step) {
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m_appliedImpulse = real_t(0.);
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Vector3 normal(0,0,0);
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for (int i=0;i<3;i++)
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{
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normal[i] = 1;
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memnew_placement(&m_jac[i],JacobianEntrySW(
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A->get_transform().basis.transposed(),
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B->get_transform().basis.transposed(),
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A->get_transform().xform(m_pivotInA) - A->get_transform().origin,
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B->get_transform().xform(m_pivotInB) - B->get_transform().origin,
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normal,
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A->get_inv_inertia(),
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A->get_inv_mass(),
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B->get_inv_inertia(),
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B->get_inv_mass()));
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normal[i] = 0;
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}
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return true;
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}
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void PinJointSW::solve(float p_step){
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Vector3 pivotAInW = A->get_transform().xform(m_pivotInA);
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Vector3 pivotBInW = B->get_transform().xform(m_pivotInB);
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Vector3 normal(0,0,0);
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// Vector3 angvelA = A->get_transform().origin.getBasis().transpose() * A->getAngularVelocity();
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// Vector3 angvelB = B->get_transform().origin.getBasis().transpose() * B->getAngularVelocity();
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for (int i=0;i<3;i++)
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{
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normal[i] = 1;
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real_t jacDiagABInv = real_t(1.) / m_jac[i].getDiagonal();
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Vector3 rel_pos1 = pivotAInW - A->get_transform().origin;
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Vector3 rel_pos2 = pivotBInW - B->get_transform().origin;
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//this jacobian entry could be re-used for all iterations
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Vector3 vel1 = A->get_velocity_in_local_point(rel_pos1);
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Vector3 vel2 = B->get_velocity_in_local_point(rel_pos2);
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Vector3 vel = vel1 - vel2;
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real_t rel_vel;
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rel_vel = normal.dot(vel);
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/*
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//velocity error (first order error)
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real_t rel_vel = m_jac[i].getRelativeVelocity(A->getLinearVelocity(),angvelA,
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B->getLinearVelocity(),angvelB);
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*/
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//positional error (zeroth order error)
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real_t depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
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real_t impulse = depth*m_tau/p_step * jacDiagABInv - m_damping * rel_vel * jacDiagABInv;
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real_t impulseClamp = m_impulseClamp;
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if (impulseClamp > 0)
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{
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if (impulse < -impulseClamp)
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impulse = -impulseClamp;
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if (impulse > impulseClamp)
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impulse = impulseClamp;
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}
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m_appliedImpulse+=impulse;
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Vector3 impulse_vector = normal * impulse;
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A->apply_impulse(pivotAInW - A->get_transform().origin,impulse_vector);
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B->apply_impulse(pivotBInW - B->get_transform().origin,-impulse_vector);
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normal[i] = 0;
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}
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}
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void PinJointSW::set_param(PhysicsServer::PinJointParam p_param,float p_value) {
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switch(p_param) {
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case PhysicsServer::PIN_JOINT_BIAS: m_tau=p_value; break;
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case PhysicsServer::PIN_JOINT_DAMPING: m_damping=p_value; break;
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case PhysicsServer::PIN_JOINT_IMPULSE_CLAMP: m_impulseClamp=p_value; break;
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}
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}
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float PinJointSW::get_param(PhysicsServer::PinJointParam p_param) const{
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switch(p_param) {
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case PhysicsServer::PIN_JOINT_BIAS: return m_tau;
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case PhysicsServer::PIN_JOINT_DAMPING: return m_damping;
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case PhysicsServer::PIN_JOINT_IMPULSE_CLAMP: return m_impulseClamp;
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}
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return 0;
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}
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PinJointSW::PinJointSW(BodySW* p_body_a,const Vector3& p_pos_a,BodySW* p_body_b,const Vector3& p_pos_b) : JointSW(_arr,2) {
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A=p_body_a;
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B=p_body_b;
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m_pivotInA=p_pos_a;
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m_pivotInB=p_pos_b;
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m_tau=0.3;
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m_damping=1;
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m_impulseClamp=0;
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m_appliedImpulse=0;
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A->add_constraint(this,0);
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B->add_constraint(this,1);
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}
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PinJointSW::~PinJointSW() {
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}
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