text: /*************************************************************************/
  /*  ray_cast_2d.cpp                                                      */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
  /*                                                                       */
  /* 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 "ray_cast_2d.h"
  
  #include "collision_object_2d.h"
  #include "core/engine.h"
  #include "physics_body_2d.h"
  #include "servers/physics_2d_server.h"
  
  void RayCast2D::set_cast_to(const Vector2 &p_point) {
  	cast_to = p_point;
  	if (is_inside_tree() && (Engine::get_singleton()->is_editor_hint() || get_tree()->is_debugging_collisions_hint())) {
  		update();
  	}
  }
  
  Vector2 RayCast2D::get_cast_to() const {
  	return cast_to;
  }
  
  void RayCast2D::set_collision_mask(uint32_t p_mask) {
  	collision_mask = p_mask;
  }
  
  uint32_t RayCast2D::get_collision_mask() const {
  	return collision_mask;
  }
  
  void RayCast2D::set_collision_mask_bit(int p_bit, bool p_value) {
  	ERR_FAIL_INDEX_MSG(p_bit, 32, "Collision mask bit must be between 0 and 31 inclusive.");
  	uint32_t mask = get_collision_mask();
  	if (p_value) {
  		mask |= 1 << p_bit;
  	} else {
  		mask &= ~(1 << p_bit);
  	}
  	set_collision_mask(mask);
  }
  
  bool RayCast2D::get_collision_mask_bit(int p_bit) const {
  	ERR_FAIL_INDEX_V_MSG(p_bit, 32, false, "Collision mask bit must be between 0 and 31 inclusive.");
  	return get_collision_mask() & (1 << p_bit);
  }
  
  bool RayCast2D::is_colliding() const {
  	return collided;
  }
  Object *RayCast2D::get_collider() const {
  	if (against == 0) {
  		return nullptr;
  	}
  
  	return ObjectDB::get_instance(against);
  }
  
  int RayCast2D::get_collider_shape() const {
  	return against_shape;
  }
  Vector2 RayCast2D::get_collision_point() const {
  	return collision_point;
  }
  Vector2 RayCast2D::get_collision_normal() const {
  	return collision_normal;
  }
  
  void RayCast2D::set_enabled(bool p_enabled) {
  	enabled = p_enabled;
  	update();
  	if (is_inside_tree() && !Engine::get_singleton()->is_editor_hint()) {
  		set_physics_process_internal(p_enabled);
  	}
  	if (!p_enabled) {
  		collided = false;
  	}
  }
  
  bool RayCast2D::is_enabled() const {
  	return enabled;
  }
  
  void RayCast2D::set_exclude_parent_body(bool p_exclude_parent_body) {
  	if (exclude_parent_body == p_exclude_parent_body) {
  		return;
  	}
  
  	exclude_parent_body = p_exclude_parent_body;
  
  	if (!is_inside_tree()) {
  		return;
  	}
  
  	if (Object::cast_to<CollisionObject2D>(get_parent())) {
  		if (exclude_parent_body) {
  			exclude.insert(Object::cast_to<CollisionObject2D>(get_parent())->get_rid());
  		} else {
  			exclude.erase(Object::cast_to<CollisionObject2D>(get_parent())->get_rid());
  		}
  	}
  }
  
  bool RayCast2D::get_exclude_parent_body() const {
  	return exclude_parent_body;
  }
  
  void RayCast2D::_notification(int p_what) {
  	switch (p_what) {
  		case NOTIFICATION_ENTER_TREE: {
  			if (enabled && !Engine::get_singleton()->is_editor_hint()) {
  				set_physics_process_internal(true);
  			} else {
  				set_physics_process_internal(false);
  			}
  
  			if (Object::cast_to<CollisionObject2D>(get_parent())) {
  				if (exclude_parent_body) {
  					exclude.insert(Object::cast_to<CollisionObject2D>(get_parent())->get_rid());
  				} else {
  					exclude.erase(Object::cast_to<CollisionObject2D>(get_parent())->get_rid());
  				}
  			}
  		} break;
  		case NOTIFICATION_EXIT_TREE: {
  			if (enabled) {
  				set_physics_process_internal(false);
  			}
  
  		} break;
  
  		case NOTIFICATION_DRAW: {
  			ERR_FAIL_COND(!is_inside_tree());
  			if (!Engine::get_singleton()->is_editor_hint() && !get_tree()->is_debugging_collisions_hint()) {
  				break;
  			}
  			_draw_debug_shape();
  		} break;
  
  		case NOTIFICATION_INTERNAL_PHYSICS_PROCESS: {
  			if (!enabled) {
  				break;
  			}
  
  			_update_raycast_state();
  
  		} break;
  	}
  }
  
  void RayCast2D::_update_raycast_state() {
  	Ref<World2D> w2d = get_world_2d();
  	ERR_FAIL_COND(w2d.is_null());
  
  	Physics2DDirectSpaceState *dss = Physics2DServer::get_singleton()->space_get_direct_state(w2d->get_space());
  	ERR_FAIL_COND(!dss);
  
  	Transform2D gt = get_global_transform();
  
  	Vector2 to = cast_to;
  	if (to == Vector2()) {
  		to = Vector2(0, 0.01);
  	}
  
  	Physics2DDirectSpaceState::RayResult rr;
  	bool prev_collision_state = collided;
  	if (dss->intersect_ray(gt.get_origin(), gt.xform(to), rr, exclude, collision_mask, collide_with_bodies, collide_with_areas)) {
  		collided = true;
  		against = rr.collider_id;
  		collision_point = rr.position;
  		collision_normal = rr.normal;
  		against_shape = rr.shape;
  	} else {
  		collided = false;
  		against = 0;
  		against_shape = 0;
  	}
  
  	if (prev_collision_state != collided) {
  		update();
  	}
  }
  
  void RayCast2D::_draw_debug_shape() {
  	Color draw_col = collided ? Color(1.0, 0.01, 0) : get_tree()->get_debug_collisions_color();
  	if (!enabled) {
  		float g = draw_col.get_v();
  		draw_col.r = g;
  		draw_col.g = g;
  		draw_col.b = g;
  	}
  
  	// Draw an arrow indicating where the RayCast is pointing to.
  	const real_t max_arrow_size = 6;
  	const real_t line_width = 1.4;
  	const real_t line_length = cast_to.length();
  	bool no_line = line_length < line_width;
  	real_t arrow_size = CLAMP(line_length * 2 / 3, line_width, max_arrow_size);
  
  	if (no_line) {
  		arrow_size = line_length;
  	} else {
  		draw_line(Vector2(), cast_to - cast_to.normalized() * arrow_size, draw_col, line_width);
  	}
  
  	Transform2D xf;
  	xf.rotate(cast_to.angle());
  	xf.translate(Vector2(no_line ? 0 : line_length - arrow_size, 0));
  
  	Vector<Vector2> pts;
  	pts.push_back(xf.xform(Vector2(arrow_size, 0)));
  	pts.push_back(xf.xform(Vector2(0, 0.5 * arrow_size)));
  	pts.push_back(xf.xform(Vector2(0, -0.5 * arrow_size)));
  
  	Vector<Color> cols;
  	cols.push_back(draw_col);
  	cols.push_back(draw_col);
  	cols.push_back(draw_col);
  
  	draw_primitive(pts, cols, Vector<Vector2>());
  }
  
  void RayCast2D::force_raycast_update() {
  	_update_raycast_state();
  }
  
  void RayCast2D::add_exception_rid(const RID &p_rid) {
  	exclude.insert(p_rid);
  }
  
  void RayCast2D::add_exception(const Object *p_object) {
  	ERR_FAIL_NULL(p_object);
  	const CollisionObject2D *co = Object::cast_to<CollisionObject2D>(p_object);
  	if (!co) {
  		return;
  	}
  	add_exception_rid(co->get_rid());
  }
  
  void RayCast2D::remove_exception_rid(const RID &p_rid) {
  	exclude.erase(p_rid);
  }
  
  void RayCast2D::remove_exception(const Object *p_object) {
  	ERR_FAIL_NULL(p_object);
  	const CollisionObject2D *co = Object::cast_to<CollisionObject2D>(p_object);
  	if (!co) {
  		return;
  	}
  	remove_exception_rid(co->get_rid());
  }
  
  void RayCast2D::clear_exceptions() {
  	exclude.clear();
  
  	if (exclude_parent_body && is_inside_tree()) {
  		CollisionObject2D *parent = Object::cast_to<CollisionObject2D>(get_parent());
  		if (parent) {
  			exclude.insert(parent->get_rid());
  		}
  	}
  }
  
  void RayCast2D::set_collide_with_areas(bool p_clip) {
  	collide_with_areas = p_clip;
  }
  
  bool RayCast2D::is_collide_with_areas_enabled() const {
  	return collide_with_areas;
  }
  
  void RayCast2D::set_collide_with_bodies(bool p_clip) {
  	collide_with_bodies = p_clip;
  }
  
  bool RayCast2D::is_collide_with_bodies_enabled() const {
  	return collide_with_bodies;
  }
  
  void RayCast2D::_bind_methods() {
  	ClassDB::bind_method(D_METHOD("set_enabled", "enabled"), &RayCast2D::set_enabled);
  	ClassDB::bind_method(D_METHOD("is_enabled"), &RayCast2D::is_enabled);
  
  	ClassDB::bind_method(D_METHOD("set_cast_to", "local_point"), &RayCast2D::set_cast_to);
  	ClassDB::bind_method(D_METHOD("get_cast_to"), &RayCast2D::get_cast_to);
  
  	ClassDB::bind_method(D_METHOD("is_colliding"), &RayCast2D::is_colliding);
  	ClassDB::bind_method(D_METHOD("force_raycast_update"), &RayCast2D::force_raycast_update);
  
  	ClassDB::bind_method(D_METHOD("get_collider"), &RayCast2D::get_collider);
  	ClassDB::bind_method(D_METHOD("get_collider_shape"), &RayCast2D::get_collider_shape);
  	ClassDB::bind_method(D_METHOD("get_collision_point"), &RayCast2D::get_collision_point);
  	ClassDB::bind_method(D_METHOD("get_collision_normal"), &RayCast2D::get_collision_normal);
  
  	ClassDB::bind_method(D_METHOD("add_exception_rid", "rid"), &RayCast2D::add_exception_rid);
  	ClassDB::bind_method(D_METHOD("add_exception", "node"), &RayCast2D::add_exception);
  
  	ClassDB::bind_method(D_METHOD("remove_exception_rid", "rid"), &RayCast2D::remove_exception_rid);
  	ClassDB::bind_method(D_METHOD("remove_exception", "node"), &RayCast2D::remove_exception);
  
  	ClassDB::bind_method(D_METHOD("clear_exceptions"), &RayCast2D::clear_exceptions);
  
  	ClassDB::bind_method(D_METHOD("set_collision_mask", "mask"), &RayCast2D::set_collision_mask);
  	ClassDB::bind_method(D_METHOD("get_collision_mask"), &RayCast2D::get_collision_mask);
  
  	ClassDB::bind_method(D_METHOD("set_collision_mask_bit", "bit", "value"), &RayCast2D::set_collision_mask_bit);
  	ClassDB::bind_method(D_METHOD("get_collision_mask_bit", "bit"), &RayCast2D::get_collision_mask_bit);
  
  	ClassDB::bind_method(D_METHOD("set_exclude_parent_body", "mask"), &RayCast2D::set_exclude_parent_body);
  	ClassDB::bind_method(D_METHOD("get_exclude_parent_body"), &RayCast2D::get_exclude_parent_body);
  
  	ClassDB::bind_method(D_METHOD("set_collide_with_areas", "enable"), &RayCast2D::set_collide_with_areas);
  	ClassDB::bind_method(D_METHOD("is_collide_with_areas_enabled"), &RayCast2D::is_collide_with_areas_enabled);
  
  	ClassDB::bind_method(D_METHOD("set_collide_with_bodies", "enable"), &RayCast2D::set_collide_with_bodies);
  	ClassDB::bind_method(D_METHOD("is_collide_with_bodies_enabled"), &RayCast2D::is_collide_with_bodies_enabled);
  
  	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "enabled"), "set_enabled", "is_enabled");
  	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "exclude_parent"), "set_exclude_parent_body", "get_exclude_parent_body");
  	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "cast_to"), "set_cast_to", "get_cast_to");
  	ADD_PROPERTY(PropertyInfo(Variant::INT, "collision_mask", PROPERTY_HINT_LAYERS_2D_PHYSICS), "set_collision_mask", "get_collision_mask");
  
  	ADD_GROUP("Collide With", "collide_with");
  	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "collide_with_areas", PROPERTY_HINT_LAYERS_3D_PHYSICS), "set_collide_with_areas", "is_collide_with_areas_enabled");
  	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "collide_with_bodies", PROPERTY_HINT_LAYERS_3D_PHYSICS), "set_collide_with_bodies", "is_collide_with_bodies_enabled");
  }
  
  RayCast2D::RayCast2D() {
  	enabled = false;
  	against = 0;
  	collided = false;
  	against_shape = 0;
  	collision_mask = 1;
  	cast_to = Vector2(0, 50);
  	exclude_parent_body = true;
  	collide_with_bodies = true;
  	collide_with_areas = false;
  }
  