Cppcheck report - Godot - branch: 3.x, commit: cd92ad0f69a842d94dc2d56f83cbd8f724ed2959 (2024-12-15): servers/physics_2d/joints_2d_sw.cpp

/**************************************************************************/
/*  joints_2d_sw.cpp                                                      */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 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,    */
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#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);
}

bool PinJoint2DSW::setup(real_t p_step) {
	if ((A->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC) && (B->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC)) {
		return false;
	}

	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;

	real_t B_inv_mass = B ? B->get_inv_mass() : 0.0;

	Transform2D 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;

	Transform2D 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;

	Transform2D K;
	K[0] = K1[0] + K2[0];
	K[1] = K1[1] + K2[1];

	if (B) {
		Transform2D 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;
}

inline Vector2 custom_cross(const Vector2 &p_vec, real_t p_other) {
	return Vector2(p_other * p_vec.y, -p_other * p_vec.x);
}

void PinJoint2DSW::solve(real_t p_step) {
	// compute relative velocity
	Vector2 vA = A->get_linear_velocity() - custom_cross(rA, A->get_angular_velocity());

	Vector2 rel_vel;
	if (B) {
		rel_vel = B->get_linear_velocity() - custom_cross(rB, 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);
<--- Variable 'anchor_A' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'anchor_A' a value by passing the value to the constructor in the initialization list.
	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);
	}
}

//////////////////////////////////////////////
//////////////////////////////////////////////
//////////////////////////////////////////////

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(real_t p_step) {
	if ((A->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC) && (B->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC)) {
		return false;
	}

	// 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);

	real_t _b = get_bias();
	gbias = (delta * -(_b == 0 ? space->get_constraint_bias() : _b) * (1.0 / p_step)).limit_length(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(real_t 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 : j.project(xf_normal)).limit_length(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);
<--- Variable 'A_groove_1' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'A_groove_1' a value by passing the value to the constructor in the initialization list.
	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(real_t p_step) {
	if ((A->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC) && (B->get_mode() <= Physics2DServer::BODY_MODE_KINEMATIC)) {
		return false;
	}

	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(real_t 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);
<--- Variable 'anchor_A' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'anchor_A' a value by passing the value to the constructor in the initialization list.
	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);
}