godot/servers/physics_2d/joints_2d_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

587 lines
15 KiB
C++

/*************************************************************************/
/* joints_2d_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. */
/*************************************************************************/
#include "joints_2d_sw.h"
#include "space_2d_sw.h"
//based on chipmunk joint constraints
/* Copyright (c) 2007 Scott Lembcke
*
* 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.
*/
static inline real_t k_scalar(Body2DSW *a,Body2DSW *b,const Vector2& rA, const Vector2& rB, const Vector2& n) {
real_t value=0;
{
value+=a->get_inv_mass();
real_t rcn = rA.cross(n);
value+=a->get_inv_inertia() * rcn * rcn;
}
if (b) {
value+=b->get_inv_mass();
real_t rcn = rB.cross(n);
value+=b->get_inv_inertia() * rcn * rcn;
}
return value;
}
static inline Vector2
relative_velocity(Body2DSW *a, Body2DSW *b, Vector2 rA, Vector2 rB){
Vector2 sum = a->get_linear_velocity() -rA.tangent() * a->get_angular_velocity();
if (b)
return (b->get_linear_velocity() -rB.tangent() * b->get_angular_velocity()) - sum;
else
return -sum;
}
static inline real_t
normal_relative_velocity(Body2DSW *a, Body2DSW *b, Vector2 rA, Vector2 rB, Vector2 n){
return relative_velocity(a, b, rA, rB).dot(n);
}
#if 0
bool PinJoint2DSW::setup(float p_step) {
Space2DSW *space = A->get_space();
ERR_FAIL_COND_V(!space,false;)
rA = A->get_transform().basis_xform(anchor_A);
rB = B?B->get_transform().basis_xform(anchor_B):anchor_B;
Vector2 gA = A->get_transform().get_origin();
Vector2 gB = B?B->get_transform().get_origin():Vector2();
Vector2 delta = gB - gA;
delta = (delta+rB) -rA;
real_t jdist = delta.length();
correct=false;
if (jdist==0)
return false; // do not correct
correct=true;
n = delta / jdist;
// calculate mass normal
mass_normal = 1.0f/k_scalar(A, B, rA, rB, n);
// calculate bias velocity
//real_t maxBias = joint->constraint.maxBias;
bias = -(get_bias()==0?space->get_constraint_bias():get_bias())*(1.0/p_step)*(jdist-dist);
bias = CLAMP(bias, -get_max_bias(), +get_max_bias());
// compute max impulse
jn_max = get_max_force() * p_step;
// apply accumulated impulse
Vector2 j = n * jn_acc;
A->apply_impulse(rA,-j);
if (B)
B->apply_impulse(rB,j);
print_line("setup");
return true;
}
void PinJoint2DSW::solve(float p_step){
if (!correct)
return;
Vector2 ln = n;
// compute relative velocity
real_t vrn = normal_relative_velocity(A,B, rA, rB, ln);
// compute normal impulse
real_t jn = (bias - vrn)*mass_normal;
real_t jnOld = jn_acc;
jn_acc = CLAMP(jnOld + jn,-jn_max,jn_max); //cpfclamp(jnOld + jn, -joint->jnMax, joint->jnMax);
jn = jn_acc - jnOld;
print_line("jn_acc: "+rtos(jn_acc));
Vector2 j = jn*ln;
A->apply_impulse(rA,-j);
if (B)
B->apply_impulse(rB,j);
}
PinJoint2DSW::PinJoint2DSW(const Vector2& p_pos,Body2DSW* p_body_a,Body2DSW* p_body_b) : Joint2DSW(_arr,p_body_b?2:1) {
A=p_body_a;
B=p_body_b;
anchor_A = p_body_a->get_inv_transform().xform(p_pos);
anchor_B = p_body_b?p_body_b->get_inv_transform().xform(p_pos):p_pos;
jn_acc=0;
dist=0;
p_body_a->add_constraint(this,0);
if (p_body_b)
p_body_b->add_constraint(this,1);
}
PinJoint2DSW::~PinJoint2DSW() {
if (A)
A->remove_constraint(this);
if (B)
B->remove_constraint(this);
}
#else
bool PinJoint2DSW::setup(float p_step) {
Space2DSW *space = A->get_space();
ERR_FAIL_COND_V(!space,false;)
rA = A->get_transform().basis_xform(anchor_A);
rB = B?B->get_transform().basis_xform(anchor_B):anchor_B;
#if 0
Vector2 gA = rA+A->get_transform().get_origin();
Vector2 gB = B?rB+B->get_transform().get_origin():rB;
VectorB delta = gB - gA;
real_t jdist = delta.length();
correct=false;
if (jdist==0)
return false; // do not correct
#endif
// deltaV = deltaV0 + K * impulse
// invM = [(1/m1 + 1/m2) * eye(2) - skew(rA) * invI1 * skew(rA) - skew(rB) * invI2 * skew(rB)]
// = [1/m1+1/m2 0 ] + invI1 * [rA.y*rA.y -rA.x*rA.y] + invI2 * [rA.y*rA.y -rA.x*rA.y]
// [ 0 1/m1+1/m2] [-rA.x*rA.y rA.x*rA.x] [-rA.x*rA.y rA.x*rA.x]
real_t B_inv_mass = B?B->get_inv_mass():0.0;
Matrix32 K1;
K1[0].x = A->get_inv_mass() + B_inv_mass; K1[1].x = 0.0f;
K1[0].y = 0.0f; K1[1].y = A->get_inv_mass() + B_inv_mass;
Matrix32 K2;
K2[0].x = A->get_inv_inertia() * rA.y * rA.y; K2[1].x = -A->get_inv_inertia() * rA.x * rA.y;
K2[0].y = -A->get_inv_inertia() * rA.x * rA.y; K2[1].y = A->get_inv_inertia() * rA.x * rA.x;
Matrix32 K;
K[0]= K1[0] + K2[0];
K[1]= K1[1] + K2[1];
if (B) {
Matrix32 K3;
K3[0].x = B->get_inv_inertia() * rB.y * rB.y; K3[1].x = -B->get_inv_inertia() * rB.x * rB.y;
K3[0].y = -B->get_inv_inertia() * rB.x * rB.y; K3[1].y = B->get_inv_inertia() * rB.x * rB.x;
K[0]+=K3[0];
K[1]+=K3[1];
}
K[0].x += softness;
K[1].y += softness;
M = K.affine_inverse();
Vector2 gA = rA+A->get_transform().get_origin();
Vector2 gB = B?rB+B->get_transform().get_origin():rB;
Vector2 delta = gB - gA;
bias = delta*-(get_bias()==0?space->get_constraint_bias():get_bias())*(1.0/p_step);
// apply accumulated impulse
A->apply_impulse(rA,-P);
if (B)
B->apply_impulse(rB,P);
return true;
}
void PinJoint2DSW::solve(float p_step){
// compute relative velocity
Vector2 vA = A->get_linear_velocity() - rA.cross(A->get_angular_velocity());
Vector2 rel_vel;
if (B)
rel_vel = B->get_linear_velocity() - rB.cross(B->get_angular_velocity()) - vA;
else
rel_vel = -vA;
Vector2 impulse = M.basis_xform(bias - rel_vel - Vector2(softness,softness) * P);
A->apply_impulse(rA,-impulse);
if (B)
B->apply_impulse(rB,impulse);
P += impulse;
}
void PinJoint2DSW::set_param(Physics2DServer::PinJointParam p_param, real_t p_value) {
if(p_param == Physics2DServer::PIN_JOINT_SOFTNESS)
softness = p_value;
}
real_t PinJoint2DSW::get_param(Physics2DServer::PinJointParam p_param) const {
if(p_param == Physics2DServer::PIN_JOINT_SOFTNESS)
return softness;
ERR_FAIL_V(0);
}
PinJoint2DSW::PinJoint2DSW(const Vector2& p_pos,Body2DSW* p_body_a,Body2DSW* p_body_b) : Joint2DSW(_arr,p_body_b?2:1) {
A=p_body_a;
B=p_body_b;
anchor_A = p_body_a->get_inv_transform().xform(p_pos);
anchor_B = p_body_b?p_body_b->get_inv_transform().xform(p_pos):p_pos;
softness=0;
p_body_a->add_constraint(this,0);
if (p_body_b)
p_body_b->add_constraint(this,1);
}
PinJoint2DSW::~PinJoint2DSW() {
if (A)
A->remove_constraint(this);
if (B)
B->remove_constraint(this);
}
#endif
//////////////////////////////////////////////
//////////////////////////////////////////////
//////////////////////////////////////////////
static inline void
k_tensor(Body2DSW *a, Body2DSW *b, Vector2 r1, Vector2 r2, Vector2 *k1, Vector2 *k2)
{
// calculate mass matrix
// If I wasn't lazy and wrote a proper matrix class, this wouldn't be so gross...
real_t k11, k12, k21, k22;
real_t m_sum = a->get_inv_mass() + b->get_inv_mass();
// start with I*m_sum
k11 = m_sum; k12 = 0.0f;
k21 = 0.0f; k22 = m_sum;
// add the influence from r1
real_t a_i_inv = a->get_inv_inertia();
real_t r1xsq = r1.x * r1.x * a_i_inv;
real_t r1ysq = r1.y * r1.y * a_i_inv;
real_t r1nxy = -r1.x * r1.y * a_i_inv;
k11 += r1ysq; k12 += r1nxy;
k21 += r1nxy; k22 += r1xsq;
// add the influnce from r2
real_t b_i_inv = b->get_inv_inertia();
real_t r2xsq = r2.x * r2.x * b_i_inv;
real_t r2ysq = r2.y * r2.y * b_i_inv;
real_t r2nxy = -r2.x * r2.y * b_i_inv;
k11 += r2ysq; k12 += r2nxy;
k21 += r2nxy; k22 += r2xsq;
// invert
real_t determinant = k11*k22 - k12*k21;
ERR_FAIL_COND(determinant== 0.0);
real_t det_inv = 1.0f/determinant;
*k1 = Vector2( k22*det_inv, -k12*det_inv);
*k2 = Vector2(-k21*det_inv, k11*det_inv);
}
static _FORCE_INLINE_ Vector2
mult_k(const Vector2& vr, const Vector2 &k1, const Vector2 &k2)
{
return Vector2(vr.dot(k1), vr.dot(k2));
}
bool GrooveJoint2DSW::setup(float p_step) {
// calculate endpoints in worldspace
Vector2 ta = A->get_transform().xform(A_groove_1);
Vector2 tb = A->get_transform().xform(A_groove_2);
Space2DSW *space=A->get_space();
// calculate axis
Vector2 n = -(tb - ta).tangent().normalized();
real_t d = ta.dot(n);
xf_normal = n;
rB = B->get_transform().basis_xform(B_anchor);
// calculate tangential distance along the axis of rB
real_t td = (B->get_transform().get_origin() + rB).cross(n);
// calculate clamping factor and rB
if(td <= ta.cross(n)){
clamp = 1.0f;
rA = ta - A->get_transform().get_origin();
} else if(td >= tb.cross(n)){
clamp = -1.0f;
rA = tb - A->get_transform().get_origin();
} else {
clamp = 0.0f;
//joint->r1 = cpvsub(cpvadd(cpvmult(cpvperp(n), -td), cpvmult(n, d)), a->p);
rA = ((-n.tangent() * -td) + n*d) - A->get_transform().get_origin();
}
// Calculate mass tensor
k_tensor(A, B, rA, rB, &k1, &k2);
// compute max impulse
jn_max = get_max_force() * p_step;
// calculate bias velocity
// cpVect delta = cpvsub(cpvadd(b->p, joint->r2), cpvadd(a->p, joint->r1));
// joint->bias = cpvclamp(cpvmult(delta, -joint->constraint.biasCoef*dt_inv), joint->constraint.maxBias);
Vector2 delta = (B->get_transform().get_origin() +rB) - (A->get_transform().get_origin() + rA);
float _b = get_bias();
_b=0.001;
gbias=(delta*-(_b==0?space->get_constraint_bias():_b)*(1.0/p_step)).clamped(get_max_bias());
// apply accumulated impulse
A->apply_impulse(rA,-jn_acc);
B->apply_impulse(rB,jn_acc);
correct=true;
return true;
}
void GrooveJoint2DSW::solve(float p_step){
// compute impulse
Vector2 vr = relative_velocity(A, B, rA,rB);
Vector2 j = mult_k(gbias-vr, k1, k2);
Vector2 jOld = jn_acc;
j+=jOld;
jn_acc = (((clamp * j.cross(xf_normal)) > 0) ? j : xf_normal.project(j)).clamped(jn_max);
j = jn_acc - jOld;
A->apply_impulse(rA,-j);
B->apply_impulse(rB,j);
}
GrooveJoint2DSW::GrooveJoint2DSW(const Vector2& p_a_groove1,const Vector2& p_a_groove2, const Vector2& p_b_anchor, Body2DSW* p_body_a,Body2DSW* p_body_b) : Joint2DSW(_arr,2) {
A=p_body_a;
B=p_body_b;
A_groove_1 = A->get_inv_transform().xform(p_a_groove1);
A_groove_2 = A->get_inv_transform().xform(p_a_groove2);
B_anchor=B->get_inv_transform().xform(p_b_anchor);
A_groove_normal = -(A_groove_2 - A_groove_1).normalized().tangent();
A->add_constraint(this,0);
B->add_constraint(this,1);
}
GrooveJoint2DSW::~GrooveJoint2DSW() {
A->remove_constraint(this);
B->remove_constraint(this);
}
//////////////////////////////////////////////
//////////////////////////////////////////////
//////////////////////////////////////////////
bool DampedSpringJoint2DSW::setup(float p_step) {
rA = A->get_transform().basis_xform(anchor_A);
rB = B->get_transform().basis_xform(anchor_B);
Vector2 delta = (B->get_transform().get_origin() + rB) - (A->get_transform().get_origin() + rA) ;
real_t dist = delta.length();
if (dist)
n=delta/dist;
else
n=Vector2();
real_t k = k_scalar(A, B, rA, rB, n);
n_mass = 1.0f/k;
target_vrn = 0.0f;
v_coef = 1.0f - Math::exp(-damping*(p_step)*k);
// apply spring force
real_t f_spring = (rest_length - dist) * stiffness;
Vector2 j = n * f_spring*(p_step);
A->apply_impulse(rA,-j);
B->apply_impulse(rB,j);
return true;
}
void DampedSpringJoint2DSW::solve(float p_step) {
// compute relative velocity
real_t vrn = normal_relative_velocity(A, B, rA, rB, n) - target_vrn;
// compute velocity loss from drag
// not 100% certain this is derived correctly, though it makes sense
real_t v_damp = -vrn*v_coef;
target_vrn = vrn + v_damp;
Vector2 j=n*v_damp*n_mass;
A->apply_impulse(rA,-j);
B->apply_impulse(rB,j);
}
void DampedSpringJoint2DSW::set_param(Physics2DServer::DampedStringParam p_param, real_t p_value) {
switch(p_param) {
case Physics2DServer::DAMPED_STRING_REST_LENGTH: {
rest_length=p_value;
} break;
case Physics2DServer::DAMPED_STRING_DAMPING: {
damping=p_value;
} break;
case Physics2DServer::DAMPED_STRING_STIFFNESS: {
stiffness=p_value;
} break;
}
}
real_t DampedSpringJoint2DSW::get_param(Physics2DServer::DampedStringParam p_param) const{
switch(p_param) {
case Physics2DServer::DAMPED_STRING_REST_LENGTH: {
return rest_length;
} break;
case Physics2DServer::DAMPED_STRING_DAMPING: {
return damping;
} break;
case Physics2DServer::DAMPED_STRING_STIFFNESS: {
return stiffness;
} break;
}
ERR_FAIL_V(0);
}
DampedSpringJoint2DSW::DampedSpringJoint2DSW(const Vector2& p_anchor_a,const Vector2& p_anchor_b, Body2DSW* p_body_a,Body2DSW* p_body_b) : Joint2DSW(_arr,2) {
A=p_body_a;
B=p_body_b;
anchor_A = A->get_inv_transform().xform(p_anchor_a);
anchor_B = B->get_inv_transform().xform(p_anchor_b);
rest_length=p_anchor_a.distance_to(p_anchor_b);
stiffness=20;
damping=1.5;
A->add_constraint(this,0);
B->add_constraint(this,1);
}
DampedSpringJoint2DSW::~DampedSpringJoint2DSW() {
A->remove_constraint(this);
B->remove_constraint(this);
}