30a608b7b9
For 2D: Raycast CCD now works the same as in 3D, it changes the body's velocity to place it at the impact position instead of generating a contact point that causes a wrong push back. For both 2D and 3D: The raycast CCD process reads and modifies body velocities, so it needs to be moved to pre_solve() instead of setup() to be processed linearly on the main thread, otherwise multithreading can cause some CCD results to be randomly lost when multiple collisions occur.
588 lines
19 KiB
C++
588 lines
19 KiB
C++
/*************************************************************************/
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/* godot_body_pair_2d.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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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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#include "godot_body_pair_2d.h"
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#include "godot_collision_solver_2d.h"
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#include "godot_space_2d.h"
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#define ACCUMULATE_IMPULSES
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#define MIN_VELOCITY 0.001
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#define MAX_BIAS_ROTATION (Math_PI / 8)
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void GodotBodyPair2D::_add_contact(const Vector2 &p_point_A, const Vector2 &p_point_B, void *p_self) {
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GodotBodyPair2D *self = (GodotBodyPair2D *)p_self;
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self->_contact_added_callback(p_point_A, p_point_B);
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}
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void GodotBodyPair2D::_contact_added_callback(const Vector2 &p_point_A, const Vector2 &p_point_B) {
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Vector2 local_A = A->get_inv_transform().basis_xform(p_point_A);
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Vector2 local_B = B->get_inv_transform().basis_xform(p_point_B - offset_B);
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int new_index = contact_count;
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ERR_FAIL_COND(new_index >= (MAX_CONTACTS + 1));
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Contact contact;
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contact.local_A = local_A;
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contact.local_B = local_B;
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contact.normal = (p_point_A - p_point_B).normalized();
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contact.used = true;
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// Attempt to determine if the contact will be reused.
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real_t recycle_radius_2 = space->get_contact_recycle_radius() * space->get_contact_recycle_radius();
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for (int i = 0; i < contact_count; i++) {
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Contact &c = contacts[i];
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if (c.local_A.distance_squared_to(local_A) < (recycle_radius_2) &&
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c.local_B.distance_squared_to(local_B) < (recycle_radius_2)) {
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contact.acc_normal_impulse = c.acc_normal_impulse;
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contact.acc_tangent_impulse = c.acc_tangent_impulse;
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contact.acc_bias_impulse = c.acc_bias_impulse;
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contact.acc_bias_impulse_center_of_mass = c.acc_bias_impulse_center_of_mass;
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c = contact;
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return;
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}
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}
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// Figure out if the contact amount must be reduced to fit the new contact.
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if (new_index == MAX_CONTACTS) {
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// Remove the contact with the minimum depth.
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const Transform2D &transform_A = A->get_transform();
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const Transform2D &transform_B = B->get_transform();
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int least_deep = -1;
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real_t min_depth;
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// Start with depth for new contact.
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{
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Vector2 global_A = transform_A.basis_xform(contact.local_A);
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Vector2 global_B = transform_B.basis_xform(contact.local_B) + offset_B;
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Vector2 axis = global_A - global_B;
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min_depth = axis.dot(contact.normal);
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}
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for (int i = 0; i < contact_count; i++) {
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const Contact &c = contacts[i];
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Vector2 global_A = transform_A.basis_xform(c.local_A);
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Vector2 global_B = transform_B.basis_xform(c.local_B) + offset_B;
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Vector2 axis = global_A - global_B;
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real_t depth = axis.dot(c.normal);
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if (depth < min_depth) {
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min_depth = depth;
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least_deep = i;
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}
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}
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if (least_deep > -1) {
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// Replace the least deep contact by the new one.
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contacts[least_deep] = contact;
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}
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return;
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}
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contacts[new_index] = contact;
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contact_count++;
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}
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void GodotBodyPair2D::_validate_contacts() {
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// Make sure to erase contacts that are no longer valid.
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real_t max_separation = space->get_contact_max_separation();
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real_t max_separation2 = max_separation * max_separation;
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const Transform2D &transform_A = A->get_transform();
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const Transform2D &transform_B = B->get_transform();
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for (int i = 0; i < contact_count; i++) {
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Contact &c = contacts[i];
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bool erase = false;
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if (!c.used) {
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// Was left behind in previous frame.
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erase = true;
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} else {
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c.used = false;
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Vector2 global_A = transform_A.basis_xform(c.local_A);
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Vector2 global_B = transform_B.basis_xform(c.local_B) + offset_B;
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Vector2 axis = global_A - global_B;
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real_t depth = axis.dot(c.normal);
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if (depth < -max_separation || (global_B + c.normal * depth - global_A).length_squared() > max_separation2) {
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erase = true;
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}
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}
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if (erase) {
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// Contact no longer needed, remove.
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if ((i + 1) < contact_count) {
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// Swap with the last one.
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SWAP(contacts[i], contacts[contact_count - 1]);
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}
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i--;
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contact_count--;
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}
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}
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}
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bool GodotBodyPair2D::_test_ccd(real_t p_step, GodotBody2D *p_A, int p_shape_A, const Transform2D &p_xform_A, GodotBody2D *p_B, int p_shape_B, const Transform2D &p_xform_B) {
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Vector2 motion = p_A->get_linear_velocity() * p_step;
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real_t mlen = motion.length();
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if (mlen < CMP_EPSILON) {
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return false;
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}
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Vector2 mnormal = motion / mlen;
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real_t min, max;
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p_A->get_shape(p_shape_A)->project_rangev(mnormal, p_xform_A, min, max);
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// Did it move enough in this direction to even attempt raycast?
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// Let's say it should move more than 1/3 the size of the object in that axis.
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bool fast_object = mlen > (max - min) * 0.3;
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if (!fast_object) {
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return false;
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}
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// Going too fast in that direction.
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// Cast a segment from support in motion normal, in the same direction of motion by motion length.
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// Support is the worst case collision point, so real collision happened before.
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int a;
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Vector2 s[2];
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p_A->get_shape(p_shape_A)->get_supports(p_xform_A.basis_xform(mnormal).normalized(), s, a);
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Vector2 from = p_xform_A.xform(s[0]);
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Vector2 to = from + motion;
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Transform2D from_inv = p_xform_B.affine_inverse();
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// Start from a little inside the bounding box.
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Vector2 local_from = from_inv.xform(from - mnormal * mlen * 0.1);
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Vector2 local_to = from_inv.xform(to);
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Vector2 rpos, rnorm;
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if (!p_B->get_shape(p_shape_B)->intersect_segment(local_from, local_to, rpos, rnorm)) {
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return false;
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}
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// Check one-way collision based on motion direction.
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if (p_A->get_shape(p_shape_A)->allows_one_way_collision() && p_B->is_shape_set_as_one_way_collision(p_shape_B)) {
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Vector2 direction = p_xform_B.get_axis(1).normalized();
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if (direction.dot(mnormal) < CMP_EPSILON) {
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collided = false;
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oneway_disabled = true;
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return false;
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}
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}
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// Shorten the linear velocity so it does not hit, but gets close enough,
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// next frame will hit softly or soft enough.
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Vector2 hitpos = p_xform_B.xform(rpos);
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real_t newlen = hitpos.distance_to(from) - (max - min) * 0.01;
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p_A->set_linear_velocity(mnormal * (newlen / p_step));
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return true;
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}
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real_t combine_bounce(GodotBody2D *A, GodotBody2D *B) {
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return CLAMP(A->get_bounce() + B->get_bounce(), 0, 1);
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}
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real_t combine_friction(GodotBody2D *A, GodotBody2D *B) {
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return ABS(MIN(A->get_friction(), B->get_friction()));
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}
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bool GodotBodyPair2D::setup(real_t p_step) {
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check_ccd = false;
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if (!A->interacts_with(B) || A->has_exception(B->get_self()) || B->has_exception(A->get_self())) {
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collided = false;
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return false;
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}
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collide_A = (A->get_mode() > PhysicsServer2D::BODY_MODE_KINEMATIC) && A->collides_with(B);
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collide_B = (B->get_mode() > PhysicsServer2D::BODY_MODE_KINEMATIC) && B->collides_with(A);
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report_contacts_only = false;
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if (!collide_A && !collide_B) {
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if ((A->get_max_contacts_reported() > 0) || (B->get_max_contacts_reported() > 0)) {
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report_contacts_only = true;
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} else {
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collided = false;
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return false;
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}
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}
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//use local A coordinates to avoid numerical issues on collision detection
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offset_B = B->get_transform().get_origin() - A->get_transform().get_origin();
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_validate_contacts();
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const Vector2 &offset_A = A->get_transform().get_origin();
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Transform2D xform_Au = A->get_transform().untranslated();
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Transform2D xform_A = xform_Au * A->get_shape_transform(shape_A);
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Transform2D xform_Bu = B->get_transform();
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xform_Bu.elements[2] -= offset_A;
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Transform2D xform_B = xform_Bu * B->get_shape_transform(shape_B);
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GodotShape2D *shape_A_ptr = A->get_shape(shape_A);
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GodotShape2D *shape_B_ptr = B->get_shape(shape_B);
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Vector2 motion_A, motion_B;
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if (A->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_SHAPE) {
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motion_A = A->get_motion();
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}
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if (B->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_SHAPE) {
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motion_B = B->get_motion();
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}
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bool prev_collided = collided;
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collided = GodotCollisionSolver2D::solve(shape_A_ptr, xform_A, motion_A, shape_B_ptr, xform_B, motion_B, _add_contact, this, &sep_axis);
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if (!collided) {
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oneway_disabled = false;
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if (A->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_RAY && collide_A) {
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check_ccd = true;
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return true;
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}
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if (B->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_RAY && collide_B) {
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check_ccd = true;
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return true;
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}
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return false;
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}
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if (oneway_disabled) {
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return false;
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}
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if (!prev_collided) {
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if (shape_B_ptr->allows_one_way_collision() && A->is_shape_set_as_one_way_collision(shape_A)) {
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Vector2 direction = xform_A.get_axis(1).normalized();
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bool valid = false;
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for (int i = 0; i < contact_count; i++) {
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Contact &c = contacts[i];
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if (c.normal.dot(direction) > -CMP_EPSILON) { //greater (normal inverted)
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continue;
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}
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valid = true;
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break;
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}
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if (!valid) {
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collided = false;
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oneway_disabled = true;
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return false;
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}
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}
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if (shape_A_ptr->allows_one_way_collision() && B->is_shape_set_as_one_way_collision(shape_B)) {
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Vector2 direction = xform_B.get_axis(1).normalized();
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bool valid = false;
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for (int i = 0; i < contact_count; i++) {
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Contact &c = contacts[i];
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if (c.normal.dot(direction) < CMP_EPSILON) { //less (normal ok)
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continue;
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}
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valid = true;
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break;
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}
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if (!valid) {
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collided = false;
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oneway_disabled = true;
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return false;
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}
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}
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}
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return true;
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}
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bool GodotBodyPair2D::pre_solve(real_t p_step) {
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if (oneway_disabled) {
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return false;
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}
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if (!collided) {
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if (check_ccd) {
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const Vector2 &offset_A = A->get_transform().get_origin();
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Transform2D xform_Au = A->get_transform().untranslated();
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Transform2D xform_A = xform_Au * A->get_shape_transform(shape_A);
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Transform2D xform_Bu = B->get_transform();
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xform_Bu.elements[2] -= offset_A;
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Transform2D xform_B = xform_Bu * B->get_shape_transform(shape_B);
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if (A->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_RAY && collide_A) {
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_test_ccd(p_step, A, shape_A, xform_A, B, shape_B, xform_B);
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}
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if (B->get_continuous_collision_detection_mode() == PhysicsServer2D::CCD_MODE_CAST_RAY && collide_B) {
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_test_ccd(p_step, B, shape_B, xform_B, A, shape_A, xform_A);
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}
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}
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return false;
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}
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real_t max_penetration = space->get_contact_max_allowed_penetration();
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real_t bias = space->get_contact_bias();
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GodotShape2D *shape_A_ptr = A->get_shape(shape_A);
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GodotShape2D *shape_B_ptr = B->get_shape(shape_B);
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if (shape_A_ptr->get_custom_bias() || shape_B_ptr->get_custom_bias()) {
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if (shape_A_ptr->get_custom_bias() == 0) {
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bias = shape_B_ptr->get_custom_bias();
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} else if (shape_B_ptr->get_custom_bias() == 0) {
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bias = shape_A_ptr->get_custom_bias();
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} else {
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bias = (shape_B_ptr->get_custom_bias() + shape_A_ptr->get_custom_bias()) * 0.5;
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}
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}
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real_t inv_dt = 1.0 / p_step;
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bool do_process = false;
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const Vector2 &offset_A = A->get_transform().get_origin();
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const Transform2D &transform_A = A->get_transform();
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const Transform2D &transform_B = B->get_transform();
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real_t inv_inertia_A = collide_A ? A->get_inv_inertia() : 0.0;
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real_t inv_inertia_B = collide_B ? B->get_inv_inertia() : 0.0;
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real_t inv_mass_A = collide_A ? A->get_inv_mass() : 0.0;
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real_t inv_mass_B = collide_B ? B->get_inv_mass() : 0.0;
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for (int i = 0; i < contact_count; i++) {
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Contact &c = contacts[i];
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c.active = false;
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Vector2 global_A = transform_A.basis_xform(c.local_A);
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Vector2 global_B = transform_B.basis_xform(c.local_B) + offset_B;
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Vector2 axis = global_A - global_B;
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real_t depth = axis.dot(c.normal);
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if (depth <= 0.0) {
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continue;
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}
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#ifdef DEBUG_ENABLED
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if (space->is_debugging_contacts()) {
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space->add_debug_contact(global_A + offset_A);
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space->add_debug_contact(global_B + offset_A);
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}
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#endif
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c.rA = global_A - A->get_center_of_mass();
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c.rB = global_B - B->get_center_of_mass() - offset_B;
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if (A->can_report_contacts()) {
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Vector2 crB(-B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x);
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A->add_contact(global_A + offset_A, -c.normal, depth, shape_A, global_B + offset_A, shape_B, B->get_instance_id(), B->get_self(), crB + B->get_linear_velocity());
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}
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if (B->can_report_contacts()) {
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Vector2 crA(-A->get_angular_velocity() * c.rA.y, A->get_angular_velocity() * c.rA.x);
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B->add_contact(global_B + offset_A, c.normal, depth, shape_B, global_A + offset_A, shape_A, A->get_instance_id(), A->get_self(), crA + A->get_linear_velocity());
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}
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if (report_contacts_only) {
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collided = false;
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continue;
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}
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// Precompute normal mass, tangent mass, and bias.
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real_t rnA = c.rA.dot(c.normal);
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real_t rnB = c.rB.dot(c.normal);
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real_t kNormal = inv_mass_A + inv_mass_B;
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kNormal += inv_inertia_A * (c.rA.dot(c.rA) - rnA * rnA) + inv_inertia_B * (c.rB.dot(c.rB) - rnB * rnB);
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c.mass_normal = 1.0f / kNormal;
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Vector2 tangent = c.normal.orthogonal();
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real_t rtA = c.rA.dot(tangent);
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|
real_t rtB = c.rB.dot(tangent);
|
|
real_t kTangent = inv_mass_A + inv_mass_B;
|
|
kTangent += inv_inertia_A * (c.rA.dot(c.rA) - rtA * rtA) + inv_inertia_B * (c.rB.dot(c.rB) - rtB * rtB);
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|
c.mass_tangent = 1.0f / kTangent;
|
|
|
|
c.bias = -bias * inv_dt * MIN(0.0f, -depth + max_penetration);
|
|
c.depth = depth;
|
|
|
|
#ifdef ACCUMULATE_IMPULSES
|
|
{
|
|
// Apply normal + friction impulse
|
|
Vector2 P = c.acc_normal_impulse * c.normal + c.acc_tangent_impulse * tangent;
|
|
|
|
if (collide_A) {
|
|
A->apply_impulse(-P, c.rA + A->get_center_of_mass());
|
|
}
|
|
if (collide_B) {
|
|
B->apply_impulse(P, c.rB + B->get_center_of_mass());
|
|
}
|
|
}
|
|
#endif
|
|
|
|
c.bounce = combine_bounce(A, B);
|
|
if (c.bounce) {
|
|
Vector2 crA(-A->get_prev_angular_velocity() * c.rA.y, A->get_prev_angular_velocity() * c.rA.x);
|
|
Vector2 crB(-B->get_prev_angular_velocity() * c.rB.y, B->get_prev_angular_velocity() * c.rB.x);
|
|
Vector2 dv = B->get_prev_linear_velocity() + crB - A->get_prev_linear_velocity() - crA;
|
|
c.bounce = c.bounce * dv.dot(c.normal);
|
|
}
|
|
|
|
c.active = true;
|
|
do_process = true;
|
|
}
|
|
|
|
return do_process;
|
|
}
|
|
|
|
void GodotBodyPair2D::solve(real_t p_step) {
|
|
if (!collided || oneway_disabled) {
|
|
return;
|
|
}
|
|
|
|
const real_t max_bias_av = MAX_BIAS_ROTATION / p_step;
|
|
|
|
real_t inv_mass_A = collide_A ? A->get_inv_mass() : 0.0;
|
|
real_t inv_mass_B = collide_B ? B->get_inv_mass() : 0.0;
|
|
|
|
for (int i = 0; i < contact_count; ++i) {
|
|
Contact &c = contacts[i];
|
|
|
|
if (!c.active) {
|
|
continue;
|
|
}
|
|
|
|
// Relative velocity at contact
|
|
|
|
Vector2 crA(-A->get_angular_velocity() * c.rA.y, A->get_angular_velocity() * c.rA.x);
|
|
Vector2 crB(-B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x);
|
|
Vector2 dv = B->get_linear_velocity() + crB - A->get_linear_velocity() - crA;
|
|
|
|
Vector2 crbA(-A->get_biased_angular_velocity() * c.rA.y, A->get_biased_angular_velocity() * c.rA.x);
|
|
Vector2 crbB(-B->get_biased_angular_velocity() * c.rB.y, B->get_biased_angular_velocity() * c.rB.x);
|
|
Vector2 dbv = B->get_biased_linear_velocity() + crbB - A->get_biased_linear_velocity() - crbA;
|
|
|
|
real_t vn = dv.dot(c.normal);
|
|
real_t vbn = dbv.dot(c.normal);
|
|
|
|
Vector2 tangent = c.normal.orthogonal();
|
|
real_t vt = dv.dot(tangent);
|
|
|
|
real_t jbn = (c.bias - vbn) * c.mass_normal;
|
|
real_t jbnOld = c.acc_bias_impulse;
|
|
c.acc_bias_impulse = MAX(jbnOld + jbn, 0.0f);
|
|
|
|
Vector2 jb = c.normal * (c.acc_bias_impulse - jbnOld);
|
|
|
|
if (collide_A) {
|
|
A->apply_bias_impulse(-jb, c.rA + A->get_center_of_mass(), max_bias_av);
|
|
}
|
|
if (collide_B) {
|
|
B->apply_bias_impulse(jb, c.rB + B->get_center_of_mass(), max_bias_av);
|
|
}
|
|
|
|
crbA = Vector2(-A->get_biased_angular_velocity() * c.rA.y, A->get_biased_angular_velocity() * c.rA.x);
|
|
crbB = Vector2(-B->get_biased_angular_velocity() * c.rB.y, B->get_biased_angular_velocity() * c.rB.x);
|
|
dbv = B->get_biased_linear_velocity() + crbB - A->get_biased_linear_velocity() - crbA;
|
|
|
|
vbn = dbv.dot(c.normal);
|
|
|
|
if (Math::abs(-vbn + c.bias) > MIN_VELOCITY) {
|
|
real_t jbn_com = (-vbn + c.bias) / (inv_mass_A + inv_mass_B);
|
|
real_t jbnOld_com = c.acc_bias_impulse_center_of_mass;
|
|
c.acc_bias_impulse_center_of_mass = MAX(jbnOld_com + jbn_com, 0.0f);
|
|
|
|
Vector2 jb_com = c.normal * (c.acc_bias_impulse_center_of_mass - jbnOld_com);
|
|
|
|
if (collide_A) {
|
|
A->apply_bias_impulse(-jb_com, A->get_center_of_mass(), 0.0f);
|
|
}
|
|
if (collide_B) {
|
|
B->apply_bias_impulse(jb_com, B->get_center_of_mass(), 0.0f);
|
|
}
|
|
}
|
|
|
|
real_t jn = -(c.bounce + vn) * c.mass_normal;
|
|
real_t jnOld = c.acc_normal_impulse;
|
|
c.acc_normal_impulse = MAX(jnOld + jn, 0.0f);
|
|
|
|
real_t friction = combine_friction(A, B);
|
|
|
|
real_t jtMax = friction * c.acc_normal_impulse;
|
|
real_t jt = -vt * c.mass_tangent;
|
|
real_t jtOld = c.acc_tangent_impulse;
|
|
c.acc_tangent_impulse = CLAMP(jtOld + jt, -jtMax, jtMax);
|
|
|
|
Vector2 j = c.normal * (c.acc_normal_impulse - jnOld) + tangent * (c.acc_tangent_impulse - jtOld);
|
|
|
|
if (collide_A) {
|
|
A->apply_impulse(-j, c.rA + A->get_center_of_mass());
|
|
}
|
|
if (collide_B) {
|
|
B->apply_impulse(j, c.rB + B->get_center_of_mass());
|
|
}
|
|
}
|
|
}
|
|
|
|
GodotBodyPair2D::GodotBodyPair2D(GodotBody2D *p_A, int p_shape_A, GodotBody2D *p_B, int p_shape_B) :
|
|
GodotConstraint2D(_arr, 2) {
|
|
A = p_A;
|
|
B = p_B;
|
|
shape_A = p_shape_A;
|
|
shape_B = p_shape_B;
|
|
space = A->get_space();
|
|
A->add_constraint(this, 0);
|
|
B->add_constraint(this, 1);
|
|
}
|
|
|
|
GodotBodyPair2D::~GodotBodyPair2D() {
|
|
A->remove_constraint(this, 0);
|
|
B->remove_constraint(this, 1);
|
|
}
|