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/*************************************************************************/
/* pin_joint_sw.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
/*
Adapted to Godot from the Bullet library.
See corresponding header file for licensing info.
*/
#include "pin_joint_sw.h"
bool PinJointSW::setup(float p_step) {
m_appliedImpulse = real_t(0.);
Vector3 normal(0,0,0);
for (int i=0;i<3;i++)
{
normal[i] = 1;
memnew_placement(&m_jac[i],JacobianEntrySW(
A->get_principal_inertia_axes().transposed(),
B->get_principal_inertia_axes().transposed(),
A->get_transform().xform(m_pivotInA) - A->get_transform().origin - A->get_center_of_mass(),
B->get_transform().xform(m_pivotInB) - B->get_transform().origin - B->get_center_of_mass(),
normal,
A->get_inv_inertia(),
A->get_inv_mass(),
B->get_inv_inertia(),
B->get_inv_mass()));
normal[i] = 0;
}
return true;
}
void PinJointSW::solve(float p_step){
Vector3 pivotAInW = A->get_transform().xform(m_pivotInA);
Vector3 pivotBInW = B->get_transform().xform(m_pivotInB);
Vector3 normal(0,0,0);
// Vector3 angvelA = A->get_transform().origin.getBasis().transpose() * A->getAngularVelocity();
// Vector3 angvelB = B->get_transform().origin.getBasis().transpose() * B->getAngularVelocity();
for (int i=0;i<3;i++)
{
normal[i] = 1;
real_t jacDiagABInv = real_t(1.) / m_jac[i].getDiagonal();
Vector3 rel_pos1 = pivotAInW - A->get_transform().origin;
Vector3 rel_pos2 = pivotBInW - B->get_transform().origin;
//this jacobian entry could be re-used for all iterations
Vector3 vel1 = A->get_velocity_in_local_point(rel_pos1);
Vector3 vel2 = B->get_velocity_in_local_point(rel_pos2);
Vector3 vel = vel1 - vel2;
real_t rel_vel;
rel_vel = normal.dot(vel);
/*
//velocity error (first order error)
real_t rel_vel = m_jac[i].getRelativeVelocity(A->getLinearVelocity(),angvelA,
B->getLinearVelocity(),angvelB);
*/
//positional error (zeroth order error)
real_t depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
real_t impulse = depth*m_tau/p_step * jacDiagABInv - m_damping * rel_vel * jacDiagABInv;
real_t impulseClamp = m_impulseClamp;
if (impulseClamp > 0)
{
if (impulse < -impulseClamp)
impulse = -impulseClamp;
if (impulse > impulseClamp)
impulse = impulseClamp;
}
m_appliedImpulse+=impulse;
Vector3 impulse_vector = normal * impulse;
A->apply_impulse(pivotAInW - A->get_transform().origin,impulse_vector);
B->apply_impulse(pivotBInW - B->get_transform().origin,-impulse_vector);
normal[i] = 0;
}
}
void PinJointSW::set_param(PhysicsServer::PinJointParam p_param,float p_value) {
switch(p_param) {
case PhysicsServer::PIN_JOINT_BIAS: m_tau=p_value; break;
case PhysicsServer::PIN_JOINT_DAMPING: m_damping=p_value; break;
case PhysicsServer::PIN_JOINT_IMPULSE_CLAMP: m_impulseClamp=p_value; break;
}
}
float PinJointSW::get_param(PhysicsServer::PinJointParam p_param) const{
switch(p_param) {
case PhysicsServer::PIN_JOINT_BIAS: return m_tau;
case PhysicsServer::PIN_JOINT_DAMPING: return m_damping;
case PhysicsServer::PIN_JOINT_IMPULSE_CLAMP: return m_impulseClamp;
}
return 0;
}
PinJointSW::PinJointSW(BodySW* p_body_a,const Vector3& p_pos_a,BodySW* p_body_b,const Vector3& p_pos_b) : JointSW(_arr,2) {
A=p_body_a;
B=p_body_b;
m_pivotInA=p_pos_a;
m_pivotInB=p_pos_b;
m_tau=0.3;
m_damping=1;
m_impulseClamp=0;
m_appliedImpulse=0;
A->add_constraint(this,0);
B->add_constraint(this,1);
}
PinJointSW::~PinJointSW() {
}
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