godot/servers/physics/joints/cone_twist_joint_sw.cpp
Rémi Verschelde d8223ffa75 Welcome in 2017, dear changelog reader!
That year should bring the long-awaited OpenGL ES 3.0 compatible renderer
with state-of-the-art rendering techniques tuned to work as low as middle
end handheld devices - without compromising with the possibilities given
for higher end desktop games of course. Great times ahead for the Godot
community and the gamers that will play our games!

(cherry picked from commit c7bc44d5ad)
2017-01-12 19:15:30 +01:00

375 lines
11 KiB
C++

/*************************************************************************/
/* 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, */
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/* 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(float 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_transform().basis.transposed(),
B->get_transform().basis.transposed(),
pivotAInW - A->get_transform().origin,
pivotBInW - B->get_transform().origin,
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, float 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;
}
}
float 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;
}