/**************************************************************************/
/*  light_3d_gizmo_plugin.cpp                                             */
/**************************************************************************/
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/*                             GODOT ENGINE                               */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "light_3d_gizmo_plugin.h"

#include "core/config/project_settings.h"
#include "editor/editor_node.h"
#include "editor/editor_settings.h"
#include "editor/editor_undo_redo_manager.h"
#include "editor/plugins/node_3d_editor_plugin.h"
#include "scene/3d/light_3d.h"

Light3DGizmoPlugin::Light3DGizmoPlugin() {
	// Enable vertex colors for the materials below as the gizmo color depends on the light color.
	create_material("lines_primary", Color(1, 1, 1), false, false, true);
	create_material("lines_secondary", Color(1, 1, 1, 0.35), false, false, true);
	create_material("lines_billboard", Color(1, 1, 1), true, false, true);

	create_icon_material("light_directional_icon", Node3DEditor::get_singleton()->get_theme_icon(SNAME("GizmoDirectionalLight"), SNAME("EditorIcons")));
	create_icon_material("light_omni_icon", Node3DEditor::get_singleton()->get_theme_icon(SNAME("GizmoLight"), SNAME("EditorIcons")));
	create_icon_material("light_spot_icon", Node3DEditor::get_singleton()->get_theme_icon(SNAME("GizmoSpotLight"), SNAME("EditorIcons")));

	create_handle_material("handles");
	create_handle_material("handles_billboard", true);
}

bool Light3DGizmoPlugin::has_gizmo(Node3D *p_spatial) {
	return Object::cast_to<Light3D>(p_spatial) != nullptr;
}

String Light3DGizmoPlugin::get_gizmo_name() const {
	return "Light3D";
}

int Light3DGizmoPlugin::get_priority() const {
	return -1;
}

String Light3DGizmoPlugin::get_handle_name(const EditorNode3DGizmo *p_gizmo, int p_id, bool p_secondary) const {
	if (p_id == 0) {
		return "Radius";
	} else {
		return "Aperture";
	}
}

Variant Light3DGizmoPlugin::get_handle_value(const EditorNode3DGizmo *p_gizmo, int p_id, bool p_secondary) const {
	Light3D *light = Object::cast_to<Light3D>(p_gizmo->get_node_3d());
	if (p_id == 0) {
		return light->get_param(Light3D::PARAM_RANGE);
	}
	if (p_id == 1) {
		return light->get_param(Light3D::PARAM_SPOT_ANGLE);
	}

	return Variant();
}

void Light3DGizmoPlugin::set_handle(const EditorNode3DGizmo *p_gizmo, int p_id, bool p_secondary, Camera3D *p_camera, const Point2 &p_point) {
	Light3D *light = Object::cast_to<Light3D>(p_gizmo->get_node_3d());
	Transform3D gt = light->get_global_transform();
	Transform3D gi = gt.affine_inverse();

	Vector3 ray_from = p_camera->project_ray_origin(p_point);
	Vector3 ray_dir = p_camera->project_ray_normal(p_point);

	Vector3 s[2] = { gi.xform(ray_from), gi.xform(ray_from + ray_dir * 4096) };
	if (p_id == 0) {
		if (Object::cast_to<SpotLight3D>(light)) {
			Vector3 ra, rb;
			Geometry3D::get_closest_points_between_segments(Vector3(), Vector3(0, 0, -4096), s[0], s[1], ra, rb);

			float d = -ra.z;
			if (Node3DEditor::get_singleton()->is_snap_enabled()) {
				d = Math::snapped(d, Node3DEditor::get_singleton()->get_translate_snap());
			}

			if (d <= 0) { // Equal is here for negative zero.
				d = 0;
			}

			light->set_param(Light3D::PARAM_RANGE, d);
		} else if (Object::cast_to<OmniLight3D>(light)) {
			Plane cp = Plane(p_camera->get_transform().basis.get_column(2), gt.origin);

			Vector3 inters;
			if (cp.intersects_ray(ray_from, ray_dir, &inters)) {
				float r = inters.distance_to(gt.origin);
				if (Node3DEditor::get_singleton()->is_snap_enabled()) {
					r = Math::snapped(r, Node3DEditor::get_singleton()->get_translate_snap());
				}

				light->set_param(Light3D::PARAM_RANGE, r);
			}
		}

	} else if (p_id == 1) {
		float a = _find_closest_angle_to_half_pi_arc(s[0], s[1], light->get_param(Light3D::PARAM_RANGE), gt);
		light->set_param(Light3D::PARAM_SPOT_ANGLE, CLAMP(a, 0.01, 89.99));
	}
}

void Light3DGizmoPlugin::commit_handle(const EditorNode3DGizmo *p_gizmo, int p_id, bool p_secondary, const Variant &p_restore, bool p_cancel) {
	Light3D *light = Object::cast_to<Light3D>(p_gizmo->get_node_3d());
	if (p_cancel) {
		light->set_param(p_id == 0 ? Light3D::PARAM_RANGE : Light3D::PARAM_SPOT_ANGLE, p_restore);

	} else if (p_id == 0) {
		EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
		ur->create_action(TTR("Change Light Radius"));
		ur->add_do_method(light, "set_param", Light3D::PARAM_RANGE, light->get_param(Light3D::PARAM_RANGE));
		ur->add_undo_method(light, "set_param", Light3D::PARAM_RANGE, p_restore);
		ur->commit_action();
	} else if (p_id == 1) {
		EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
		ur->create_action(TTR("Change Light Radius"));
		ur->add_do_method(light, "set_param", Light3D::PARAM_SPOT_ANGLE, light->get_param(Light3D::PARAM_SPOT_ANGLE));
		ur->add_undo_method(light, "set_param", Light3D::PARAM_SPOT_ANGLE, p_restore);
		ur->commit_action();
	}
}

void Light3DGizmoPlugin::redraw(EditorNode3DGizmo *p_gizmo) {
	Light3D *light = Object::cast_to<Light3D>(p_gizmo->get_node_3d());

	Color color = light->get_color().srgb_to_linear() * light->get_correlated_color().srgb_to_linear();
	color = color.linear_to_srgb();
	// Make the gizmo color as bright as possible for better visibility
	color.set_hsv(color.get_h(), color.get_s(), 1);

	p_gizmo->clear();

	if (Object::cast_to<DirectionalLight3D>(light)) {
		Ref<Material> material = get_material("lines_primary", p_gizmo);
		Ref<Material> icon = get_material("light_directional_icon", p_gizmo);

		const int arrow_points = 7;
		const float arrow_length = 1.5;

		Vector3 arrow[arrow_points] = {
			Vector3(0, 0, -1),
			Vector3(0, 0.8, 0),
			Vector3(0, 0.3, 0),
			Vector3(0, 0.3, arrow_length),
			Vector3(0, -0.3, arrow_length),
			Vector3(0, -0.3, 0),
			Vector3(0, -0.8, 0)
		};

		int arrow_sides = 2;

		Vector<Vector3> lines;

		for (int i = 0; i < arrow_sides; i++) {
			for (int j = 0; j < arrow_points; j++) {
				Basis ma(Vector3(0, 0, 1), Math_PI * i / arrow_sides);

				Vector3 v1 = arrow[j] - Vector3(0, 0, arrow_length);
				Vector3 v2 = arrow[(j + 1) % arrow_points] - Vector3(0, 0, arrow_length);

				lines.push_back(ma.xform(v1));
				lines.push_back(ma.xform(v2));
			}
		}

		p_gizmo->add_lines(lines, material, false, color);
		p_gizmo->add_unscaled_billboard(icon, 0.05, color);
	}

	if (Object::cast_to<OmniLight3D>(light)) {
		// Use both a billboard circle and 3 non-billboard circles for a better sphere-like representation
		const Ref<Material> lines_material = get_material("lines_secondary", p_gizmo);
		const Ref<Material> lines_billboard_material = get_material("lines_billboard", p_gizmo);
		const Ref<Material> icon = get_material("light_omni_icon", p_gizmo);

		OmniLight3D *on = Object::cast_to<OmniLight3D>(light);
		const float r = on->get_param(Light3D::PARAM_RANGE);
		Vector<Vector3> points;
		Vector<Vector3> points_billboard;

		for (int i = 0; i < 120; i++) {
			// Create a circle
			const float ra = Math::deg_to_rad((float)(i * 3));
			const float rb = Math::deg_to_rad((float)((i + 1) * 3));
			const Point2 a = Vector2(Math::sin(ra), Math::cos(ra)) * r;
			const Point2 b = Vector2(Math::sin(rb), Math::cos(rb)) * r;

			// Draw axis-aligned circles
			points.push_back(Vector3(a.x, 0, a.y));
			points.push_back(Vector3(b.x, 0, b.y));
			points.push_back(Vector3(0, a.x, a.y));
			points.push_back(Vector3(0, b.x, b.y));
			points.push_back(Vector3(a.x, a.y, 0));
			points.push_back(Vector3(b.x, b.y, 0));

			// Draw a billboarded circle
			points_billboard.push_back(Vector3(a.x, a.y, 0));
			points_billboard.push_back(Vector3(b.x, b.y, 0));
		}

		p_gizmo->add_lines(points, lines_material, true, color);
		p_gizmo->add_lines(points_billboard, lines_billboard_material, true, color);
		p_gizmo->add_unscaled_billboard(icon, 0.05, color);

		Vector<Vector3> handles;
		handles.push_back(Vector3(r, 0, 0));
		p_gizmo->add_handles(handles, get_material("handles_billboard"), Vector<int>(), true);
	}

	if (Object::cast_to<SpotLight3D>(light)) {
		const Ref<Material> material_primary = get_material("lines_primary", p_gizmo);
		const Ref<Material> material_secondary = get_material("lines_secondary", p_gizmo);
		const Ref<Material> icon = get_material("light_spot_icon", p_gizmo);

		Vector<Vector3> points_primary;
		Vector<Vector3> points_secondary;
		SpotLight3D *sl = Object::cast_to<SpotLight3D>(light);

		float r = sl->get_param(Light3D::PARAM_RANGE);
		float w = r * Math::sin(Math::deg_to_rad(sl->get_param(Light3D::PARAM_SPOT_ANGLE)));
		float d = r * Math::cos(Math::deg_to_rad(sl->get_param(Light3D::PARAM_SPOT_ANGLE)));

		for (int i = 0; i < 120; i++) {
			// Draw a circle
			const float ra = Math::deg_to_rad((float)(i * 3));
			const float rb = Math::deg_to_rad((float)((i + 1) * 3));
			const Point2 a = Vector2(Math::sin(ra), Math::cos(ra)) * w;
			const Point2 b = Vector2(Math::sin(rb), Math::cos(rb)) * w;

			points_primary.push_back(Vector3(a.x, a.y, -d));
			points_primary.push_back(Vector3(b.x, b.y, -d));

			if (i % 15 == 0) {
				// Draw 8 lines from the cone origin to the sides of the circle
				points_secondary.push_back(Vector3(a.x, a.y, -d));
				points_secondary.push_back(Vector3());
			}
		}

		points_primary.push_back(Vector3(0, 0, -r));
		points_primary.push_back(Vector3());

		p_gizmo->add_lines(points_primary, material_primary, false, color);
		p_gizmo->add_lines(points_secondary, material_secondary, false, color);

		Vector<Vector3> handles = {
			Vector3(0, 0, -r),
			Vector3(w, 0, -d)
		};

		p_gizmo->add_handles(handles, get_material("handles"));
		p_gizmo->add_unscaled_billboard(icon, 0.05, color);
	}
}

float Light3DGizmoPlugin::_find_closest_angle_to_half_pi_arc(const Vector3 &p_from, const Vector3 &p_to, float p_arc_radius, const Transform3D &p_arc_xform) {
	//bleh, discrete is simpler
	static const int arc_test_points = 64;
	float min_d = 1e20;
	Vector3 min_p;

	for (int i = 0; i < arc_test_points; i++) {
		float a = i * Math_PI * 0.5 / arc_test_points;
		float an = (i + 1) * Math_PI * 0.5 / arc_test_points;
		Vector3 p = Vector3(Math::cos(a), 0, -Math::sin(a)) * p_arc_radius;
		Vector3 n = Vector3(Math::cos(an), 0, -Math::sin(an)) * p_arc_radius;

		Vector3 ra, rb;
		Geometry3D::get_closest_points_between_segments(p, n, p_from, p_to, ra, rb);

		float d = ra.distance_to(rb);
		if (d < min_d) {
			min_d = d;
			min_p = ra;
		}
	}

	//min_p = p_arc_xform.affine_inverse().xform(min_p);
	float a = (Math_PI * 0.5) - Vector2(min_p.x, -min_p.z).angle();
	return Math::rad_to_deg(a);
}