/*************************************************************************/
/*  sky.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 "sky.h"

#include "core/io/image_loader.h"

void Sky::set_radiance_size(RadianceSize p_size) {
	ERR_FAIL_INDEX(p_size, RADIANCE_SIZE_MAX);

	radiance_size = p_size;
	_radiance_changed();
}

Sky::RadianceSize Sky::get_radiance_size() const {
	return radiance_size;
}

void Sky::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_radiance_size", "size"), &Sky::set_radiance_size);
	ClassDB::bind_method(D_METHOD("get_radiance_size"), &Sky::get_radiance_size);

	// Don't expose 1024 and 2048 in the property hint as these sizes will cause GPU hangs on many systems.
	ADD_PROPERTY(PropertyInfo(Variant::INT, "radiance_size", PROPERTY_HINT_ENUM, "32,64,128,256,512"), "set_radiance_size", "get_radiance_size");

	BIND_ENUM_CONSTANT(RADIANCE_SIZE_32);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_64);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_128);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_256);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_512);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_1024);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_2048);
	BIND_ENUM_CONSTANT(RADIANCE_SIZE_MAX);
}

Sky::Sky() {
	radiance_size = RADIANCE_SIZE_128;
}

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

void PanoramaSky::_radiance_changed() {
	if (panorama.is_valid()) {
		static const int size[RADIANCE_SIZE_MAX] = {
			32, 64, 128, 256, 512, 1024, 2048
		};
		VS::get_singleton()->sky_set_texture(sky, panorama->get_rid(), size[get_radiance_size()]);
	}
}

void PanoramaSky::set_panorama(const Ref<Texture> &p_panorama) {
	panorama = p_panorama;

	if (panorama.is_valid()) {
		_radiance_changed();

	} else {
		VS::get_singleton()->sky_set_texture(sky, RID(), 0);
	}
}

Ref<Texture> PanoramaSky::get_panorama() const {
	return panorama;
}

RID PanoramaSky::get_rid() const {
	return sky;
}

void PanoramaSky::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_panorama", "texture"), &PanoramaSky::set_panorama);
	ClassDB::bind_method(D_METHOD("get_panorama"), &PanoramaSky::get_panorama);

	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "panorama", PROPERTY_HINT_RESOURCE_TYPE, "Texture"), "set_panorama", "get_panorama");
}

PanoramaSky::PanoramaSky() {
	sky = VS::get_singleton()->sky_create();
}

PanoramaSky::~PanoramaSky() {
	VS::get_singleton()->free(sky);
}
//////////////////////////////////

void ProceduralSky::_radiance_changed() {
	if (update_queued) {
		return; //do nothing yet
	}

	static const int size[RADIANCE_SIZE_MAX] = {
		32, 64, 128, 256, 512, 1024, 2048
	};
	VS::get_singleton()->sky_set_texture(sky, texture, size[get_radiance_size()]);
}

Ref<Image> ProceduralSky::_generate_sky() {
	update_queued = false;

	PoolVector<uint8_t> imgdata;

	static const int size[TEXTURE_SIZE_MAX] = {
		256, 512, 1024, 2048, 4096
	};

	int w = size[texture_size];
	int h = w / 2;

	imgdata.resize(w * h * 4); //RGBE

	{
		PoolVector<uint8_t>::Write dataw = imgdata.write();

		uint32_t *ptr = (uint32_t *)dataw.ptr();

		Color sky_top_linear = sky_top_color.to_linear();
		Color sky_horizon_linear = sky_horizon_color.to_linear();

		Color ground_bottom_linear = ground_bottom_color.to_linear();
		Color ground_horizon_linear = ground_horizon_color.to_linear();

		Color sun_linear;
		sun_linear.r = sun_color.r * sun_energy;
		sun_linear.g = sun_color.g * sun_energy;
		sun_linear.b = sun_color.b * sun_energy;

		Vector3 sun(0, 0, -1);

		sun = Basis(Vector3(1, 0, 0), Math::deg2rad(sun_latitude)).xform(sun);
		sun = Basis(Vector3(0, 1, 0), Math::deg2rad(sun_longitude)).xform(sun);

		sun.normalize();

		for (int i = 0; i < w; i++) {
			float u = float(i) / (w - 1);
			float phi = u * 2.0 * Math_PI;

			for (int j = 0; j < h; j++) {
				float v = float(j) / (h - 1);
				float theta = v * Math_PI;

				Vector3 normal(
						Math::sin(phi) * Math::sin(theta) * -1.0,
						Math::cos(theta),
						Math::cos(phi) * Math::sin(theta) * -1.0);

				normal.normalize();

				float v_angle = Math::acos(CLAMP(normal.y, -1.0, 1.0));

				Color color;

				if (normal.y < 0) {
					//ground

					float c = (v_angle - (Math_PI * 0.5)) / (Math_PI * 0.5);
					color = ground_horizon_linear.linear_interpolate(ground_bottom_linear, Math::ease(c, ground_curve));
					color.r *= ground_energy;
					color.g *= ground_energy;
					color.b *= ground_energy;
				} else {
					float c = v_angle / (Math_PI * 0.5);
					color = sky_horizon_linear.linear_interpolate(sky_top_linear, Math::ease(1.0 - c, sky_curve));
					color.r *= sky_energy;
					color.g *= sky_energy;
					color.b *= sky_energy;

					float sun_angle = Math::rad2deg(Math::acos(CLAMP(sun.dot(normal), -1.0, 1.0)));

					if (sun_angle < sun_angle_min) {
						color = color.blend(sun_linear);
					} else if (sun_angle < sun_angle_max) {
						float c2 = (sun_angle - sun_angle_min) / (sun_angle_max - sun_angle_min);
						c2 = Math::ease(c2, sun_curve);

						color = color.blend(sun_linear).linear_interpolate(color, c2);
					}
				}

				ptr[j * w + i] = color.to_rgbe9995();
			}
		}
	}

	Ref<Image> image;
	image.instance();
	image->create(w, h, false, Image::FORMAT_RGBE9995, imgdata);

	return image;
}

void ProceduralSky::set_sky_top_color(const Color &p_sky_top) {
	sky_top_color = p_sky_top;
	_queue_update();
}

Color ProceduralSky::get_sky_top_color() const {
	return sky_top_color;
}

void ProceduralSky::set_sky_horizon_color(const Color &p_sky_horizon) {
	sky_horizon_color = p_sky_horizon;
	_queue_update();
}
Color ProceduralSky::get_sky_horizon_color() const {
	return sky_horizon_color;
}

void ProceduralSky::set_sky_curve(float p_curve) {
	sky_curve = p_curve;
	_queue_update();
}
float ProceduralSky::get_sky_curve() const {
	return sky_curve;
}

void ProceduralSky::set_sky_energy(float p_energy) {
	sky_energy = p_energy;
	_queue_update();
}
float ProceduralSky::get_sky_energy() const {
	return sky_energy;
}

void ProceduralSky::set_ground_bottom_color(const Color &p_ground_bottom) {
	ground_bottom_color = p_ground_bottom;
	_queue_update();
}
Color ProceduralSky::get_ground_bottom_color() const {
	return ground_bottom_color;
}

void ProceduralSky::set_ground_horizon_color(const Color &p_ground_horizon) {
	ground_horizon_color = p_ground_horizon;
	_queue_update();
}
Color ProceduralSky::get_ground_horizon_color() const {
	return ground_horizon_color;
}

void ProceduralSky::set_ground_curve(float p_curve) {
	ground_curve = p_curve;
	_queue_update();
}
float ProceduralSky::get_ground_curve() const {
	return ground_curve;
}

void ProceduralSky::set_ground_energy(float p_energy) {
	ground_energy = p_energy;
	_queue_update();
}
float ProceduralSky::get_ground_energy() const {
	return ground_energy;
}

void ProceduralSky::set_sun_color(const Color &p_sun) {
	sun_color = p_sun;
	_queue_update();
}
Color ProceduralSky::get_sun_color() const {
	return sun_color;
}

void ProceduralSky::set_sun_latitude(float p_angle) {
	sun_latitude = p_angle;
	_queue_update();
}
float ProceduralSky::get_sun_latitude() const {
	return sun_latitude;
}

void ProceduralSky::set_sun_longitude(float p_angle) {
	sun_longitude = p_angle;
	_queue_update();
}
float ProceduralSky::get_sun_longitude() const {
	return sun_longitude;
}

void ProceduralSky::set_sun_angle_min(float p_angle) {
	sun_angle_min = p_angle;
	_queue_update();
}
float ProceduralSky::get_sun_angle_min() const {
	return sun_angle_min;
}

void ProceduralSky::set_sun_angle_max(float p_angle) {
	sun_angle_max = p_angle;
	_queue_update();
}
float ProceduralSky::get_sun_angle_max() const {
	return sun_angle_max;
}

void ProceduralSky::set_sun_curve(float p_curve) {
	sun_curve = p_curve;
	_queue_update();
}
float ProceduralSky::get_sun_curve() const {
	return sun_curve;
}

void ProceduralSky::set_sun_energy(float p_energy) {
	sun_energy = p_energy;
	_queue_update();
}
float ProceduralSky::get_sun_energy() const {
	return sun_energy;
}

void ProceduralSky::set_texture_size(TextureSize p_size) {
	ERR_FAIL_INDEX(p_size, TEXTURE_SIZE_MAX);

	texture_size = p_size;
	_queue_update();
}
ProceduralSky::TextureSize ProceduralSky::get_texture_size() const {
	return texture_size;
}

Ref<Image> ProceduralSky::get_data() const {
	return panorama->duplicate();
}

RID ProceduralSky::get_rid() const {
	return sky;
}

void ProceduralSky::_update_sky() {
	bool use_thread = true;
	if (first_time) {
		use_thread = false;
		first_time = false;
	}
#ifdef NO_THREADS
	use_thread = false;
#endif
	if (use_thread) {
		if (!sky_thread.is_started()) {
			sky_thread.start(_thread_function, this);
			regen_queued = false;
		} else {
			regen_queued = true;
		}

	} else {
		panorama = _generate_sky();
		VS::get_singleton()->texture_allocate(texture, panorama->get_width(), panorama->get_height(), 0, Image::FORMAT_RGBE9995, VS::TEXTURE_TYPE_2D, VS::TEXTURE_FLAG_FILTER | VS::TEXTURE_FLAG_REPEAT);
		VS::get_singleton()->texture_set_data(texture, panorama);
		_radiance_changed();
	}
}

void ProceduralSky::_queue_update() {
	if (update_queued) {
		return;
	}

	update_queued = true;
	call_deferred("_update_sky");
}

void ProceduralSky::_thread_done(const Ref<Image> &p_image) {
	ERR_FAIL_COND(p_image.is_null());

	panorama = p_image;
	VS::get_singleton()->texture_allocate(texture, panorama->get_width(), panorama->get_height(), 0, Image::FORMAT_RGBE9995, VS::TEXTURE_TYPE_2D, VS::TEXTURE_FLAG_FILTER | VS::TEXTURE_FLAG_REPEAT);
	VS::get_singleton()->texture_set_data(texture, panorama);
	_radiance_changed();
	sky_thread.wait_to_finish();
	if (regen_queued) {
		sky_thread.start(_thread_function, this);
		regen_queued = false;
	}
}

void ProceduralSky::_thread_function(void *p_ud) {
	ProceduralSky *psky = (ProceduralSky *)p_ud;
	psky->call_deferred("_thread_done", psky->_generate_sky());
}

void ProceduralSky::_bind_methods() {
	ClassDB::bind_method(D_METHOD("_update_sky"), &ProceduralSky::_update_sky);

	ClassDB::bind_method(D_METHOD("set_sky_top_color", "color"), &ProceduralSky::set_sky_top_color);
	ClassDB::bind_method(D_METHOD("get_sky_top_color"), &ProceduralSky::get_sky_top_color);

	ClassDB::bind_method(D_METHOD("set_sky_horizon_color", "color"), &ProceduralSky::set_sky_horizon_color);
	ClassDB::bind_method(D_METHOD("get_sky_horizon_color"), &ProceduralSky::get_sky_horizon_color);

	ClassDB::bind_method(D_METHOD("set_sky_curve", "curve"), &ProceduralSky::set_sky_curve);
	ClassDB::bind_method(D_METHOD("get_sky_curve"), &ProceduralSky::get_sky_curve);

	ClassDB::bind_method(D_METHOD("set_sky_energy", "energy"), &ProceduralSky::set_sky_energy);
	ClassDB::bind_method(D_METHOD("get_sky_energy"), &ProceduralSky::get_sky_energy);

	ClassDB::bind_method(D_METHOD("set_ground_bottom_color", "color"), &ProceduralSky::set_ground_bottom_color);
	ClassDB::bind_method(D_METHOD("get_ground_bottom_color"), &ProceduralSky::get_ground_bottom_color);

	ClassDB::bind_method(D_METHOD("set_ground_horizon_color", "color"), &ProceduralSky::set_ground_horizon_color);
	ClassDB::bind_method(D_METHOD("get_ground_horizon_color"), &ProceduralSky::get_ground_horizon_color);

	ClassDB::bind_method(D_METHOD("set_ground_curve", "curve"), &ProceduralSky::set_ground_curve);
	ClassDB::bind_method(D_METHOD("get_ground_curve"), &ProceduralSky::get_ground_curve);

	ClassDB::bind_method(D_METHOD("set_ground_energy", "energy"), &ProceduralSky::set_ground_energy);
	ClassDB::bind_method(D_METHOD("get_ground_energy"), &ProceduralSky::get_ground_energy);

	ClassDB::bind_method(D_METHOD("set_sun_color", "color"), &ProceduralSky::set_sun_color);
	ClassDB::bind_method(D_METHOD("get_sun_color"), &ProceduralSky::get_sun_color);

	ClassDB::bind_method(D_METHOD("set_sun_latitude", "degrees"), &ProceduralSky::set_sun_latitude);
	ClassDB::bind_method(D_METHOD("get_sun_latitude"), &ProceduralSky::get_sun_latitude);

	ClassDB::bind_method(D_METHOD("set_sun_longitude", "degrees"), &ProceduralSky::set_sun_longitude);
	ClassDB::bind_method(D_METHOD("get_sun_longitude"), &ProceduralSky::get_sun_longitude);

	ClassDB::bind_method(D_METHOD("set_sun_angle_min", "degrees"), &ProceduralSky::set_sun_angle_min);
	ClassDB::bind_method(D_METHOD("get_sun_angle_min"), &ProceduralSky::get_sun_angle_min);

	ClassDB::bind_method(D_METHOD("set_sun_angle_max", "degrees"), &ProceduralSky::set_sun_angle_max);
	ClassDB::bind_method(D_METHOD("get_sun_angle_max"), &ProceduralSky::get_sun_angle_max);

	ClassDB::bind_method(D_METHOD("set_sun_curve", "curve"), &ProceduralSky::set_sun_curve);
	ClassDB::bind_method(D_METHOD("get_sun_curve"), &ProceduralSky::get_sun_curve);

	ClassDB::bind_method(D_METHOD("set_sun_energy", "energy"), &ProceduralSky::set_sun_energy);
	ClassDB::bind_method(D_METHOD("get_sun_energy"), &ProceduralSky::get_sun_energy);

	ClassDB::bind_method(D_METHOD("set_texture_size", "size"), &ProceduralSky::set_texture_size);
	ClassDB::bind_method(D_METHOD("get_texture_size"), &ProceduralSky::get_texture_size);

	ClassDB::bind_method(D_METHOD("_thread_done", "image"), &ProceduralSky::_thread_done);

	ADD_GROUP("Sky", "sky_");
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "sky_top_color"), "set_sky_top_color", "get_sky_top_color");
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "sky_horizon_color"), "set_sky_horizon_color", "get_sky_horizon_color");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sky_curve", PROPERTY_HINT_EXP_EASING), "set_sky_curve", "get_sky_curve");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sky_energy", PROPERTY_HINT_RANGE, "0,64,0.01"), "set_sky_energy", "get_sky_energy");

	ADD_GROUP("Ground", "ground_");
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "ground_bottom_color"), "set_ground_bottom_color", "get_ground_bottom_color");
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "ground_horizon_color"), "set_ground_horizon_color", "get_ground_horizon_color");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "ground_curve", PROPERTY_HINT_EXP_EASING), "set_ground_curve", "get_ground_curve");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "ground_energy", PROPERTY_HINT_RANGE, "0,64,0.01"), "set_ground_energy", "get_ground_energy");

	ADD_GROUP("Sun", "sun_");
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "sun_color"), "set_sun_color", "get_sun_color");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_latitude", PROPERTY_HINT_RANGE, "-180,180,0.01"), "set_sun_latitude", "get_sun_latitude");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_longitude", PROPERTY_HINT_RANGE, "-180,180,0.01"), "set_sun_longitude", "get_sun_longitude");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_angle_min", PROPERTY_HINT_RANGE, "0,360,0.01"), "set_sun_angle_min", "get_sun_angle_min");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_angle_max", PROPERTY_HINT_RANGE, "0,360,0.01"), "set_sun_angle_max", "get_sun_angle_max");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_curve", PROPERTY_HINT_EXP_EASING), "set_sun_curve", "get_sun_curve");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "sun_energy", PROPERTY_HINT_RANGE, "0,64,0.01"), "set_sun_energy", "get_sun_energy");

	ADD_GROUP("Texture", "texture_");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "texture_size", PROPERTY_HINT_ENUM, "256,512,1024,2048,4096"), "set_texture_size", "get_texture_size");

	BIND_ENUM_CONSTANT(TEXTURE_SIZE_256);
	BIND_ENUM_CONSTANT(TEXTURE_SIZE_512);
	BIND_ENUM_CONSTANT(TEXTURE_SIZE_1024);
	BIND_ENUM_CONSTANT(TEXTURE_SIZE_2048);
	BIND_ENUM_CONSTANT(TEXTURE_SIZE_4096);
	BIND_ENUM_CONSTANT(TEXTURE_SIZE_MAX);
}

ProceduralSky::ProceduralSky(bool p_desaturate) {
	sky = VS::get_singleton()->sky_create();
	texture = RID_PRIME(VS::get_singleton()->texture_create());

	update_queued = false;
	sky_top_color = Color::hex(0xa5d6f1ff);
	sky_horizon_color = Color::hex(0xd6eafaff);
	sky_curve = 0.09;
	sky_energy = 1;

	ground_bottom_color = Color::hex(0x282f36ff);
	ground_horizon_color = Color::hex(0x6c655fff);
	ground_curve = 0.02;
	ground_energy = 1;

	if (p_desaturate) {
		sky_top_color.set_hsv(sky_top_color.get_h(), 0, sky_top_color.get_v());
		sky_horizon_color.set_hsv(sky_horizon_color.get_h(), 0, sky_horizon_color.get_v());
		ground_bottom_color.set_hsv(ground_bottom_color.get_h(), 0, ground_bottom_color.get_v());
		ground_horizon_color.set_hsv(ground_horizon_color.get_h(), 0, ground_horizon_color.get_v());
	}
	sun_color = Color(1, 1, 1);
	sun_latitude = 35;
	sun_longitude = 0;
	sun_angle_min = 1;
	sun_angle_max = 100;
	sun_curve = 0.05;
	sun_energy = 1;

	texture_size = TEXTURE_SIZE_1024;
	regen_queued = false;
	first_time = true;

	_queue_update();
}

ProceduralSky::~ProceduralSky() {
	if (sky_thread.is_started()) {
		sky_thread.wait_to_finish();
	}
	VS::get_singleton()->free(sky);
	VS::get_singleton()->free(texture);
}