152 lines
5.5 KiB
C++
152 lines
5.5 KiB
C++
/*************************************************************************/
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/* pin_joint_sw.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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/*
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Adapted to Godot from the Bullet library.
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See corresponding header file for licensing info.
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*/
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#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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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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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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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)
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: 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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