godot/servers/physics_2d/area_2d_sw.cpp
PouleyKetchoupp 9c9e528e3e Fix point gravity calculation
Removing the + 1 in point gravity formula when using distance scale to
make it more accurate for standard gravitation.

Fixes precession in orbits for games using gravitation.

Also moved gravity calculation to area to use it for both rigid bodies
and soft bodies in 3D (same change in 2D for consistency).

Co-authored-by: Ryan Peach <ryan.peach@keysight.com>
2021-08-24 09:32:28 -07:00

317 lines
9.6 KiB
C++

/*************************************************************************/
/* area_2d_sw.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
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/* "Software"), to deal in the Software without restriction, including */
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/*************************************************************************/
#include "area_2d_sw.h"
#include "body_2d_sw.h"
#include "space_2d_sw.h"
Area2DSW::BodyKey::BodyKey(Body2DSW *p_body, uint32_t p_body_shape, uint32_t p_area_shape) {
rid = p_body->get_self();
instance_id = p_body->get_instance_id();
body_shape = p_body_shape;
area_shape = p_area_shape;
}
Area2DSW::BodyKey::BodyKey(Area2DSW *p_body, uint32_t p_body_shape, uint32_t p_area_shape) {
rid = p_body->get_self();
instance_id = p_body->get_instance_id();
body_shape = p_body_shape;
area_shape = p_area_shape;
}
void Area2DSW::_shapes_changed() {
if (!moved_list.in_list() && get_space()) {
get_space()->area_add_to_moved_list(&moved_list);
}
}
void Area2DSW::set_transform(const Transform2D &p_transform) {
if (!moved_list.in_list() && get_space()) {
get_space()->area_add_to_moved_list(&moved_list);
}
_set_transform(p_transform);
_set_inv_transform(p_transform.affine_inverse());
}
void Area2DSW::set_space(Space2DSW *p_space) {
if (get_space()) {
if (monitor_query_list.in_list()) {
get_space()->area_remove_from_monitor_query_list(&monitor_query_list);
}
if (moved_list.in_list()) {
get_space()->area_remove_from_moved_list(&moved_list);
}
}
monitored_bodies.clear();
monitored_areas.clear();
_set_space(p_space);
}
void Area2DSW::set_monitor_callback(ObjectID p_id, const StringName &p_method) {
if (p_id == monitor_callback_id) {
monitor_callback_method = p_method;
return;
}
_unregister_shapes();
monitor_callback_id = p_id;
monitor_callback_method = p_method;
monitored_bodies.clear();
monitored_areas.clear();
_shape_changed();
if (!moved_list.in_list() && get_space()) {
get_space()->area_add_to_moved_list(&moved_list);
}
}
void Area2DSW::set_area_monitor_callback(ObjectID p_id, const StringName &p_method) {
if (p_id == area_monitor_callback_id) {
area_monitor_callback_method = p_method;
return;
}
_unregister_shapes();
area_monitor_callback_id = p_id;
area_monitor_callback_method = p_method;
monitored_bodies.clear();
monitored_areas.clear();
_shape_changed();
if (!moved_list.in_list() && get_space()) {
get_space()->area_add_to_moved_list(&moved_list);
}
}
void Area2DSW::set_space_override_mode(PhysicsServer2D::AreaSpaceOverrideMode p_mode) {
bool do_override = p_mode != PhysicsServer2D::AREA_SPACE_OVERRIDE_DISABLED;
if (do_override == (space_override_mode != PhysicsServer2D::AREA_SPACE_OVERRIDE_DISABLED)) {
return;
}
_unregister_shapes();
space_override_mode = p_mode;
_shape_changed();
}
void Area2DSW::set_param(PhysicsServer2D::AreaParameter p_param, const Variant &p_value) {
switch (p_param) {
case PhysicsServer2D::AREA_PARAM_GRAVITY:
gravity = p_value;
break;
case PhysicsServer2D::AREA_PARAM_GRAVITY_VECTOR:
gravity_vector = p_value;
break;
case PhysicsServer2D::AREA_PARAM_GRAVITY_IS_POINT:
gravity_is_point = p_value;
break;
case PhysicsServer2D::AREA_PARAM_GRAVITY_DISTANCE_SCALE:
gravity_distance_scale = p_value;
break;
case PhysicsServer2D::AREA_PARAM_GRAVITY_POINT_ATTENUATION:
point_attenuation = p_value;
break;
case PhysicsServer2D::AREA_PARAM_LINEAR_DAMP:
linear_damp = p_value;
break;
case PhysicsServer2D::AREA_PARAM_ANGULAR_DAMP:
angular_damp = p_value;
break;
case PhysicsServer2D::AREA_PARAM_PRIORITY:
priority = p_value;
break;
}
}
Variant Area2DSW::get_param(PhysicsServer2D::AreaParameter p_param) const {
switch (p_param) {
case PhysicsServer2D::AREA_PARAM_GRAVITY:
return gravity;
case PhysicsServer2D::AREA_PARAM_GRAVITY_VECTOR:
return gravity_vector;
case PhysicsServer2D::AREA_PARAM_GRAVITY_IS_POINT:
return gravity_is_point;
case PhysicsServer2D::AREA_PARAM_GRAVITY_DISTANCE_SCALE:
return gravity_distance_scale;
case PhysicsServer2D::AREA_PARAM_GRAVITY_POINT_ATTENUATION:
return point_attenuation;
case PhysicsServer2D::AREA_PARAM_LINEAR_DAMP:
return linear_damp;
case PhysicsServer2D::AREA_PARAM_ANGULAR_DAMP:
return angular_damp;
case PhysicsServer2D::AREA_PARAM_PRIORITY:
return priority;
}
return Variant();
}
void Area2DSW::_queue_monitor_update() {
ERR_FAIL_COND(!get_space());
if (!monitor_query_list.in_list()) {
get_space()->area_add_to_monitor_query_list(&monitor_query_list);
}
}
void Area2DSW::set_monitorable(bool p_monitorable) {
if (monitorable == p_monitorable) {
return;
}
monitorable = p_monitorable;
_set_static(!monitorable);
}
void Area2DSW::call_queries() {
if (monitor_callback_id.is_valid() && !monitored_bodies.is_empty()) {
Variant res[5];
Variant *resptr[5];
for (int i = 0; i < 5; i++) {
resptr[i] = &res[i];
}
Object *obj = ObjectDB::get_instance(monitor_callback_id);
if (!obj) {
monitored_bodies.clear();
monitor_callback_id = ObjectID();
return;
}
for (Map<BodyKey, BodyState>::Element *E = monitored_bodies.front(); E;) {
if (E->get().state == 0) { // Nothing happened
Map<BodyKey, BodyState>::Element *next = E->next();
monitored_bodies.erase(E);
E = next;
continue;
}
res[0] = E->get().state > 0 ? PhysicsServer2D::AREA_BODY_ADDED : PhysicsServer2D::AREA_BODY_REMOVED;
res[1] = E->key().rid;
res[2] = E->key().instance_id;
res[3] = E->key().body_shape;
res[4] = E->key().area_shape;
Map<BodyKey, BodyState>::Element *next = E->next();
monitored_bodies.erase(E);
E = next;
Callable::CallError ce;
obj->call(monitor_callback_method, (const Variant **)resptr, 5, ce);
}
}
if (area_monitor_callback_id.is_valid() && !monitored_areas.is_empty()) {
Variant res[5];
Variant *resptr[5];
for (int i = 0; i < 5; i++) {
resptr[i] = &res[i];
}
Object *obj = ObjectDB::get_instance(area_monitor_callback_id);
if (!obj) {
monitored_areas.clear();
area_monitor_callback_id = ObjectID();
return;
}
for (Map<BodyKey, BodyState>::Element *E = monitored_areas.front(); E;) {
if (E->get().state == 0) { // Nothing happened
Map<BodyKey, BodyState>::Element *next = E->next();
monitored_areas.erase(E);
E = next;
continue;
}
res[0] = E->get().state > 0 ? PhysicsServer2D::AREA_BODY_ADDED : PhysicsServer2D::AREA_BODY_REMOVED;
res[1] = E->key().rid;
res[2] = E->key().instance_id;
res[3] = E->key().body_shape;
res[4] = E->key().area_shape;
Map<BodyKey, BodyState>::Element *next = E->next();
monitored_areas.erase(E);
E = next;
Callable::CallError ce;
obj->call(area_monitor_callback_method, (const Variant **)resptr, 5, ce);
}
}
}
void Area2DSW::compute_gravity(const Vector2 &p_position, Vector2 &r_gravity) const {
if (is_gravity_point()) {
const real_t gravity_distance_scale = get_gravity_distance_scale();
Vector2 v = get_transform().xform(get_gravity_vector()) - p_position;
if (gravity_distance_scale > 0) {
const real_t v_length = v.length();
if (v_length > 0) {
const real_t v_scaled = v_length * gravity_distance_scale;
r_gravity = (v.normalized() * (get_gravity() / (v_scaled * v_scaled)));
} else {
r_gravity = Vector2();
}
} else {
r_gravity = v.normalized() * get_gravity();
}
} else {
r_gravity = get_gravity_vector() * get_gravity();
}
}
Area2DSW::Area2DSW() :
CollisionObject2DSW(TYPE_AREA),
monitor_query_list(this),
moved_list(this) {
_set_static(true); //areas are not active by default
space_override_mode = PhysicsServer2D::AREA_SPACE_OVERRIDE_DISABLED;
gravity = 9.80665;
gravity_vector = Vector2(0, -1);
gravity_is_point = false;
gravity_distance_scale = 0;
point_attenuation = 1;
angular_damp = 1.0;
linear_damp = 0.1;
priority = 0;
monitorable = false;
}
Area2DSW::~Area2DSW() {
}