/*************************************************************************/ /* cone_twist_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 "cone_twist_joint_sw.h" static void plane_space(const Vector3& n, Vector3& p, Vector3& q) { if (Math::abs(n.z) > 0.707106781186547524400844362) { // choose p in y-z plane real_t a = n[1]*n[1] + n[2]*n[2]; real_t k = 1.0/Math::sqrt(a); p=Vector3(0,-n[2]*k,n[1]*k); // set q = n x p q=Vector3(a*k,-n[0]*p[2],n[0]*p[1]); } else { // choose p in x-y plane real_t a = n.x*n.x + n.y*n.y; real_t k = 1.0/Math::sqrt(a); p=Vector3(-n.y*k,n.x*k,0); // set q = n x p q=Vector3(-n.z*p.y,n.z*p.x,a*k); } } static _FORCE_INLINE_ real_t atan2fast(real_t y, real_t x) { real_t coeff_1 = Math_PI / 4.0f; real_t coeff_2 = 3.0f * coeff_1; real_t abs_y = Math::abs(y); real_t angle; if (x >= 0.0f) { real_t r = (x - abs_y) / (x + abs_y); angle = coeff_1 - coeff_1 * r; } else { real_t r = (x + abs_y) / (abs_y - x); angle = coeff_2 - coeff_1 * r; } return (y < 0.0f) ? -angle : angle; } ConeTwistJointSW::ConeTwistJointSW(BodySW* rbA,BodySW* rbB,const Transform& rbAFrame, const Transform& rbBFrame) : JointSW(_arr,2) { A=rbA; B=rbB; m_rbAFrame=rbAFrame; m_rbBFrame=rbBFrame; m_swingSpan1 = Math_PI/4.0; m_swingSpan2 = Math_PI/4.0; m_twistSpan = Math_PI*2; m_biasFactor = 0.3f; m_relaxationFactor = 1.0f; m_solveTwistLimit = false; m_solveSwingLimit = false; A->add_constraint(this,0); B->add_constraint(this,1); m_appliedImpulse=0; } bool ConeTwistJointSW::setup(real_t p_step) { m_appliedImpulse = real_t(0.); //set bias, sign, clear accumulator m_swingCorrection = real_t(0.); m_twistLimitSign = real_t(0.); m_solveTwistLimit = false; m_solveSwingLimit = false; m_accTwistLimitImpulse = real_t(0.); m_accSwingLimitImpulse = real_t(0.); if (!m_angularOnly) { Vector3 pivotAInW = A->get_transform().xform(m_rbAFrame.origin); Vector3 pivotBInW = B->get_transform().xform(m_rbBFrame.origin); Vector3 relPos = pivotBInW - pivotAInW; Vector3 normal[3]; if (relPos.length_squared() > CMP_EPSILON) { normal[0] = relPos.normalized(); } else { normal[0]=Vector3(real_t(1.0),0,0); } plane_space(normal[0], normal[1], normal[2]); for (int i=0;i<3;i++) { memnew_placement(&m_jac[i], JacobianEntrySW( A->get_principal_inertia_axes().transposed(), B->get_principal_inertia_axes().transposed(), pivotAInW - A->get_transform().origin - A->get_center_of_mass(), pivotBInW - B->get_transform().origin - B->get_center_of_mass(), normal[i], A->get_inv_inertia(), A->get_inv_mass(), B->get_inv_inertia(), B->get_inv_mass())); } } Vector3 b1Axis1,b1Axis2,b1Axis3; Vector3 b2Axis1,b2Axis2; b1Axis1 = A->get_transform().basis.xform( this->m_rbAFrame.basis.get_axis(0) ); b2Axis1 = B->get_transform().basis.xform( this->m_rbBFrame.basis.get_axis(0) ); real_t swing1=real_t(0.),swing2 = real_t(0.); real_t swx=real_t(0.),swy = real_t(0.); real_t thresh = real_t(10.); real_t fact; // Get Frame into world space if (m_swingSpan1 >= real_t(0.05f)) { b1Axis2 = A->get_transform().basis.xform( this->m_rbAFrame.basis.get_axis(1) ); //swing1 = btAtan2Fast( b2Axis1.dot(b1Axis2),b2Axis1.dot(b1Axis1) ); swx = b2Axis1.dot(b1Axis1); swy = b2Axis1.dot(b1Axis2); swing1 = atan2fast(swy, swx); fact = (swy*swy + swx*swx) * thresh * thresh; fact = fact / (fact + real_t(1.0)); swing1 *= fact; } if (m_swingSpan2 >= real_t(0.05f)) { b1Axis3 = A->get_transform().basis.xform( this->m_rbAFrame.basis.get_axis(2) ); //swing2 = btAtan2Fast( b2Axis1.dot(b1Axis3),b2Axis1.dot(b1Axis1) ); swx = b2Axis1.dot(b1Axis1); swy = b2Axis1.dot(b1Axis3); swing2 = atan2fast(swy, swx); fact = (swy*swy + swx*swx) * thresh * thresh; fact = fact / (fact + real_t(1.0)); swing2 *= fact; } real_t RMaxAngle1Sq = 1.0f / (m_swingSpan1*m_swingSpan1); real_t RMaxAngle2Sq = 1.0f / (m_swingSpan2*m_swingSpan2); real_t EllipseAngle = Math::abs(swing1*swing1)* RMaxAngle1Sq + Math::abs(swing2*swing2) * RMaxAngle2Sq; if (EllipseAngle > 1.0f) { m_swingCorrection = EllipseAngle-1.0f; m_solveSwingLimit = true; // Calculate necessary axis & factors m_swingAxis = b2Axis1.cross(b1Axis2* b2Axis1.dot(b1Axis2) + b1Axis3* b2Axis1.dot(b1Axis3)); m_swingAxis.normalize(); real_t swingAxisSign = (b2Axis1.dot(b1Axis1) >= 0.0f) ? 1.0f : -1.0f; m_swingAxis *= swingAxisSign; m_kSwing = real_t(1.) / (A->compute_angular_impulse_denominator(m_swingAxis) + B->compute_angular_impulse_denominator(m_swingAxis)); } // Twist limits if (m_twistSpan >= real_t(0.)) { Vector3 b2Axis2 = B->get_transform().basis.xform( this->m_rbBFrame.basis.get_axis(1) ); Quat rotationArc = Quat(b2Axis1,b1Axis1); Vector3 TwistRef = rotationArc.xform(b2Axis2); real_t twist = atan2fast( TwistRef.dot(b1Axis3), TwistRef.dot(b1Axis2) ); real_t lockedFreeFactor = (m_twistSpan > real_t(0.05f)) ? m_limitSoftness : real_t(0.); if (twist <= -m_twistSpan*lockedFreeFactor) { m_twistCorrection = -(twist + m_twistSpan); m_solveTwistLimit = true; m_twistAxis = (b2Axis1 + b1Axis1) * 0.5f; m_twistAxis.normalize(); m_twistAxis *= -1.0f; m_kTwist = real_t(1.) / (A->compute_angular_impulse_denominator(m_twistAxis) + B->compute_angular_impulse_denominator(m_twistAxis)); } else if (twist > m_twistSpan*lockedFreeFactor) { m_twistCorrection = (twist - m_twistSpan); m_solveTwistLimit = true; m_twistAxis = (b2Axis1 + b1Axis1) * 0.5f; m_twistAxis.normalize(); m_kTwist = real_t(1.) / (A->compute_angular_impulse_denominator(m_twistAxis) + B->compute_angular_impulse_denominator(m_twistAxis)); } } return true; } void ConeTwistJointSW::solve(real_t timeStep) { Vector3 pivotAInW = A->get_transform().xform(m_rbAFrame.origin); Vector3 pivotBInW = B->get_transform().xform(m_rbBFrame.origin); real_t tau = real_t(0.3); //linear part if (!m_angularOnly) { Vector3 rel_pos1 = pivotAInW - A->get_transform().origin; Vector3 rel_pos2 = pivotBInW - B->get_transform().origin; Vector3 vel1 = A->get_velocity_in_local_point(rel_pos1); Vector3 vel2 = B->get_velocity_in_local_point(rel_pos2); Vector3 vel = vel1 - vel2; for (int i=0;i<3;i++) { const Vector3& normal = m_jac[i].m_linearJointAxis; real_t jacDiagABInv = real_t(1.) / m_jac[i].getDiagonal(); real_t rel_vel; rel_vel = normal.dot(vel); //positional error (zeroth order error) real_t depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal real_t impulse = depth*tau/timeStep * jacDiagABInv - rel_vel * jacDiagABInv; 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); } } { ///solve angular part const Vector3& angVelA = A->get_angular_velocity(); const Vector3& angVelB = B->get_angular_velocity(); // solve swing limit if (m_solveSwingLimit) { real_t amplitude = ((angVelB - angVelA).dot( m_swingAxis )*m_relaxationFactor*m_relaxationFactor + m_swingCorrection*(real_t(1.)/timeStep)*m_biasFactor); real_t impulseMag = amplitude * m_kSwing; // Clamp the accumulated impulse real_t temp = m_accSwingLimitImpulse; m_accSwingLimitImpulse = MAX(m_accSwingLimitImpulse + impulseMag, real_t(0.0) ); impulseMag = m_accSwingLimitImpulse - temp; Vector3 impulse = m_swingAxis * impulseMag; A->apply_torque_impulse(impulse); B->apply_torque_impulse(-impulse); } // solve twist limit if (m_solveTwistLimit) { real_t amplitude = ((angVelB - angVelA).dot( m_twistAxis )*m_relaxationFactor*m_relaxationFactor + m_twistCorrection*(real_t(1.)/timeStep)*m_biasFactor ); real_t impulseMag = amplitude * m_kTwist; // Clamp the accumulated impulse real_t temp = m_accTwistLimitImpulse; m_accTwistLimitImpulse = MAX(m_accTwistLimitImpulse + impulseMag, real_t(0.0) ); impulseMag = m_accTwistLimitImpulse - temp; Vector3 impulse = m_twistAxis * impulseMag; A->apply_torque_impulse(impulse); B->apply_torque_impulse(-impulse); } } } void ConeTwistJointSW::set_param(PhysicsServer::ConeTwistJointParam p_param, real_t p_value) { switch(p_param) { case PhysicsServer::CONE_TWIST_JOINT_SWING_SPAN: { m_swingSpan1=p_value; m_swingSpan2=p_value; } break; case PhysicsServer::CONE_TWIST_JOINT_TWIST_SPAN: { m_twistSpan=p_value; } break; case PhysicsServer::CONE_TWIST_JOINT_BIAS: { m_biasFactor=p_value; } break; case PhysicsServer::CONE_TWIST_JOINT_SOFTNESS: { m_limitSoftness=p_value; } break; case PhysicsServer::CONE_TWIST_JOINT_RELAXATION: { m_relaxationFactor=p_value; } break; } } real_t ConeTwistJointSW::get_param(PhysicsServer::ConeTwistJointParam p_param) const{ switch(p_param) { case PhysicsServer::CONE_TWIST_JOINT_SWING_SPAN: { return m_swingSpan1; } break; case PhysicsServer::CONE_TWIST_JOINT_TWIST_SPAN: { return m_twistSpan; } break; case PhysicsServer::CONE_TWIST_JOINT_BIAS: { return m_biasFactor; } break; case PhysicsServer::CONE_TWIST_JOINT_SOFTNESS: { return m_limitSoftness; } break; case PhysicsServer::CONE_TWIST_JOINT_RELAXATION: { return m_relaxationFactor; } break; } return 0; }