/**************************************************************************/
/*  light_storage.cpp                                                     */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
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#ifdef GLES3_ENABLED

#include "light_storage.h"
#include "../rasterizer_gles3.h"
#include "../rasterizer_scene_gles3.h"
#include "config.h"
#include "core/config/project_settings.h"
#include "texture_storage.h"

using namespace GLES3;

LightStorage *LightStorage::singleton = nullptr;

LightStorage *LightStorage::get_singleton() {
	return singleton;
}

LightStorage::LightStorage() {
	singleton = this;

	directional_shadow.size = GLOBAL_GET("rendering/lights_and_shadows/directional_shadow/size");
	directional_shadow.use_16_bits = GLOBAL_GET("rendering/lights_and_shadows/directional_shadow/16_bits");

	// lightmap_probe_capture_update_speed = GLOBAL_GET("rendering/lightmapping/probe_capture/update_speed");
}

LightStorage::~LightStorage() {
	singleton = nullptr;
}

/* Light API */

void LightStorage::_light_initialize(RID p_light, RS::LightType p_type) {
	Light light;
	light.type = p_type;

	light.param[RS::LIGHT_PARAM_ENERGY] = 1.0;
	light.param[RS::LIGHT_PARAM_INDIRECT_ENERGY] = 1.0;
	light.param[RS::LIGHT_PARAM_VOLUMETRIC_FOG_ENERGY] = 1.0;
	light.param[RS::LIGHT_PARAM_SPECULAR] = 0.5;
	light.param[RS::LIGHT_PARAM_RANGE] = 1.0;
	light.param[RS::LIGHT_PARAM_SIZE] = 0.0;
	light.param[RS::LIGHT_PARAM_ATTENUATION] = 1.0;
	light.param[RS::LIGHT_PARAM_SPOT_ANGLE] = 45;
	light.param[RS::LIGHT_PARAM_SPOT_ATTENUATION] = 1.0;
	light.param[RS::LIGHT_PARAM_SHADOW_MAX_DISTANCE] = 0;
	light.param[RS::LIGHT_PARAM_SHADOW_SPLIT_1_OFFSET] = 0.1;
	light.param[RS::LIGHT_PARAM_SHADOW_SPLIT_2_OFFSET] = 0.3;
	light.param[RS::LIGHT_PARAM_SHADOW_SPLIT_3_OFFSET] = 0.6;
	light.param[RS::LIGHT_PARAM_SHADOW_FADE_START] = 0.8;
	light.param[RS::LIGHT_PARAM_SHADOW_NORMAL_BIAS] = 1.0;
	light.param[RS::LIGHT_PARAM_SHADOW_OPACITY] = 1.0;
	light.param[RS::LIGHT_PARAM_SHADOW_BIAS] = 0.02;
	light.param[RS::LIGHT_PARAM_SHADOW_BLUR] = 0;
	light.param[RS::LIGHT_PARAM_SHADOW_PANCAKE_SIZE] = 20.0;
	light.param[RS::LIGHT_PARAM_TRANSMITTANCE_BIAS] = 0.05;
	light.param[RS::LIGHT_PARAM_INTENSITY] = p_type == RS::LIGHT_DIRECTIONAL ? 100000.0 : 1000.0;

	light_owner.initialize_rid(p_light, light);
}

RID LightStorage::directional_light_allocate() {
	return light_owner.allocate_rid();
}

void LightStorage::directional_light_initialize(RID p_rid) {
	_light_initialize(p_rid, RS::LIGHT_DIRECTIONAL);
}

RID LightStorage::omni_light_allocate() {
	return light_owner.allocate_rid();
}

void LightStorage::omni_light_initialize(RID p_rid) {
	_light_initialize(p_rid, RS::LIGHT_OMNI);
}

RID LightStorage::spot_light_allocate() {
	return light_owner.allocate_rid();
}

void LightStorage::spot_light_initialize(RID p_rid) {
	_light_initialize(p_rid, RS::LIGHT_SPOT);
}

void LightStorage::light_free(RID p_rid) {
	light_set_projector(p_rid, RID()); //clear projector

	// delete the texture
	Light *light = light_owner.get_or_null(p_rid);
	light->dependency.deleted_notify(p_rid);
	light_owner.free(p_rid);
}

void LightStorage::light_set_color(RID p_light, const Color &p_color) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->color = p_color;
}

void LightStorage::light_set_param(RID p_light, RS::LightParam p_param, float p_value) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);
	ERR_FAIL_INDEX(p_param, RS::LIGHT_PARAM_MAX);

	if (light->param[p_param] == p_value) {
		return;
	}

	switch (p_param) {
		case RS::LIGHT_PARAM_RANGE:
		case RS::LIGHT_PARAM_SPOT_ANGLE:
		case RS::LIGHT_PARAM_SHADOW_MAX_DISTANCE:
		case RS::LIGHT_PARAM_SHADOW_SPLIT_1_OFFSET:
		case RS::LIGHT_PARAM_SHADOW_SPLIT_2_OFFSET:
		case RS::LIGHT_PARAM_SHADOW_SPLIT_3_OFFSET:
		case RS::LIGHT_PARAM_SHADOW_NORMAL_BIAS:
		case RS::LIGHT_PARAM_SHADOW_PANCAKE_SIZE:
		case RS::LIGHT_PARAM_SHADOW_BIAS: {
			light->version++;
			light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
		} break;
		case RS::LIGHT_PARAM_SIZE: {
			if ((light->param[p_param] > CMP_EPSILON) != (p_value > CMP_EPSILON)) {
				//changing from no size to size and the opposite
				light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT_SOFT_SHADOW_AND_PROJECTOR);
			}
		} break;
		default: {
		}
	}

	light->param[p_param] = p_value;
}

void LightStorage::light_set_shadow(RID p_light, bool p_enabled) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);
	light->shadow = p_enabled;

	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

void LightStorage::light_set_projector(RID p_light, RID p_texture) {
	GLES3::TextureStorage *texture_storage = GLES3::TextureStorage::get_singleton();
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	if (light->projector == p_texture) {
		return;
	}

	if (light->type != RS::LIGHT_DIRECTIONAL && light->projector.is_valid()) {
		texture_storage->texture_remove_from_decal_atlas(light->projector, light->type == RS::LIGHT_OMNI);
	}

	light->projector = p_texture;

	if (light->type != RS::LIGHT_DIRECTIONAL) {
		if (light->projector.is_valid()) {
			texture_storage->texture_add_to_decal_atlas(light->projector, light->type == RS::LIGHT_OMNI);
		}
		light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT_SOFT_SHADOW_AND_PROJECTOR);
	}
}

void LightStorage::light_set_negative(RID p_light, bool p_enable) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->negative = p_enable;
}

void LightStorage::light_set_cull_mask(RID p_light, uint32_t p_mask) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->cull_mask = p_mask;

	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

void LightStorage::light_set_distance_fade(RID p_light, bool p_enabled, float p_begin, float p_shadow, float p_length) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->distance_fade = p_enabled;
	light->distance_fade_begin = p_begin;
	light->distance_fade_shadow = p_shadow;
	light->distance_fade_length = p_length;
}

void LightStorage::light_set_reverse_cull_face_mode(RID p_light, bool p_enabled) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->reverse_cull = p_enabled;

	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

void LightStorage::light_set_bake_mode(RID p_light, RS::LightBakeMode p_bake_mode) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->bake_mode = p_bake_mode;

	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

void LightStorage::light_omni_set_shadow_mode(RID p_light, RS::LightOmniShadowMode p_mode) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->omni_shadow_mode = p_mode;

	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

RS::LightOmniShadowMode LightStorage::light_omni_get_shadow_mode(RID p_light) {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, RS::LIGHT_OMNI_SHADOW_CUBE);

	return light->omni_shadow_mode;
}

void LightStorage::light_directional_set_shadow_mode(RID p_light, RS::LightDirectionalShadowMode p_mode) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->directional_shadow_mode = p_mode;
	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

void LightStorage::light_directional_set_blend_splits(RID p_light, bool p_enable) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->directional_blend_splits = p_enable;
	light->version++;
	light->dependency.changed_notify(Dependency::DEPENDENCY_CHANGED_LIGHT);
}

bool LightStorage::light_directional_get_blend_splits(RID p_light) const {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, false);

	return light->directional_blend_splits;
}

void LightStorage::light_directional_set_sky_mode(RID p_light, RS::LightDirectionalSkyMode p_mode) {
	Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL(light);

	light->directional_sky_mode = p_mode;
}

RS::LightDirectionalSkyMode LightStorage::light_directional_get_sky_mode(RID p_light) const {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, RS::LIGHT_DIRECTIONAL_SKY_MODE_LIGHT_AND_SKY);

	return light->directional_sky_mode;
}

RS::LightDirectionalShadowMode LightStorage::light_directional_get_shadow_mode(RID p_light) {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, RS::LIGHT_DIRECTIONAL_SHADOW_ORTHOGONAL);

	return light->directional_shadow_mode;
}

RS::LightBakeMode LightStorage::light_get_bake_mode(RID p_light) {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, RS::LIGHT_BAKE_DISABLED);

	return light->bake_mode;
}

uint64_t LightStorage::light_get_version(RID p_light) const {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, 0);

	return light->version;
}

uint32_t LightStorage::light_get_cull_mask(RID p_light) const {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, 0);

	return light->cull_mask;
}

AABB LightStorage::light_get_aabb(RID p_light) const {
	const Light *light = light_owner.get_or_null(p_light);
	ERR_FAIL_NULL_V(light, AABB());

	switch (light->type) {
		case RS::LIGHT_SPOT: {
			float len = light->param[RS::LIGHT_PARAM_RANGE];
			float size = Math::tan(Math::deg_to_rad(light->param[RS::LIGHT_PARAM_SPOT_ANGLE])) * len;
			return AABB(Vector3(-size, -size, -len), Vector3(size * 2, size * 2, len));
		};
		case RS::LIGHT_OMNI: {
			float r = light->param[RS::LIGHT_PARAM_RANGE];
			return AABB(-Vector3(r, r, r), Vector3(r, r, r) * 2);
		};
		case RS::LIGHT_DIRECTIONAL: {
			return AABB();
		};
	}

	ERR_FAIL_V(AABB());
}

/* LIGHT INSTANCE API */

RID LightStorage::light_instance_create(RID p_light) {
	RID li = light_instance_owner.make_rid(LightInstance());

	LightInstance *light_instance = light_instance_owner.get_or_null(li);

	light_instance->self = li;
	light_instance->light = p_light;
	light_instance->light_type = light_get_type(p_light);

	return li;
}

void LightStorage::light_instance_free(RID p_light_instance) {
	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL(light_instance);

	// Remove from shadow atlases.
	for (const RID &E : light_instance->shadow_atlases) {
		ShadowAtlas *shadow_atlas = shadow_atlas_owner.get_or_null(E);
		ERR_CONTINUE(!shadow_atlas->shadow_owners.has(p_light_instance));
		uint32_t key = shadow_atlas->shadow_owners[p_light_instance];
		uint32_t q = (key >> QUADRANT_SHIFT) & 0x3;
		uint32_t s = key & SHADOW_INDEX_MASK;

		shadow_atlas->quadrants[q].shadows.write[s].owner = RID();

		shadow_atlas->shadow_owners.erase(p_light_instance);
	}

	light_instance_owner.free(p_light_instance);
}

void LightStorage::light_instance_set_transform(RID p_light_instance, const Transform3D &p_transform) {
	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL(light_instance);

	light_instance->transform = p_transform;
}

void LightStorage::light_instance_set_aabb(RID p_light_instance, const AABB &p_aabb) {
	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL(light_instance);

	light_instance->aabb = p_aabb;
}

void LightStorage::light_instance_set_shadow_transform(RID p_light_instance, const Projection &p_projection, const Transform3D &p_transform, float p_far, float p_split, int p_pass, float p_shadow_texel_size, float p_bias_scale, float p_range_begin, const Vector2 &p_uv_scale) {
	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL(light_instance);

	ERR_FAIL_INDEX(p_pass, 6);

	light_instance->shadow_transform[p_pass].camera = p_projection;
	light_instance->shadow_transform[p_pass].transform = p_transform;
	light_instance->shadow_transform[p_pass].farplane = p_far;
	light_instance->shadow_transform[p_pass].split = p_split;
	light_instance->shadow_transform[p_pass].bias_scale = p_bias_scale;
	light_instance->shadow_transform[p_pass].range_begin = p_range_begin;
	light_instance->shadow_transform[p_pass].shadow_texel_size = p_shadow_texel_size;
	light_instance->shadow_transform[p_pass].uv_scale = p_uv_scale;
}

void LightStorage::light_instance_mark_visible(RID p_light_instance) {
	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL(light_instance);

	light_instance->last_scene_pass = RasterizerSceneGLES3::get_singleton()->get_scene_pass();
}

/* PROBE API */

RID LightStorage::reflection_probe_allocate() {
	return RID();
}

void LightStorage::reflection_probe_initialize(RID p_rid) {
}

void LightStorage::reflection_probe_free(RID p_rid) {
}

void LightStorage::reflection_probe_set_update_mode(RID p_probe, RS::ReflectionProbeUpdateMode p_mode) {
}

void LightStorage::reflection_probe_set_intensity(RID p_probe, float p_intensity) {
}

void LightStorage::reflection_probe_set_ambient_mode(RID p_probe, RS::ReflectionProbeAmbientMode p_mode) {
}

void LightStorage::reflection_probe_set_ambient_color(RID p_probe, const Color &p_color) {
}

void LightStorage::reflection_probe_set_ambient_energy(RID p_probe, float p_energy) {
}

void LightStorage::reflection_probe_set_max_distance(RID p_probe, float p_distance) {
}

void LightStorage::reflection_probe_set_size(RID p_probe, const Vector3 &p_size) {
}

void LightStorage::reflection_probe_set_origin_offset(RID p_probe, const Vector3 &p_offset) {
}

void LightStorage::reflection_probe_set_as_interior(RID p_probe, bool p_enable) {
}

void LightStorage::reflection_probe_set_enable_box_projection(RID p_probe, bool p_enable) {
}

void LightStorage::reflection_probe_set_enable_shadows(RID p_probe, bool p_enable) {
}

void LightStorage::reflection_probe_set_cull_mask(RID p_probe, uint32_t p_layers) {
}

void LightStorage::reflection_probe_set_resolution(RID p_probe, int p_resolution) {
}

AABB LightStorage::reflection_probe_get_aabb(RID p_probe) const {
	return AABB();
}

RS::ReflectionProbeUpdateMode LightStorage::reflection_probe_get_update_mode(RID p_probe) const {
	return RenderingServer::REFLECTION_PROBE_UPDATE_ONCE;
}

uint32_t LightStorage::reflection_probe_get_cull_mask(RID p_probe) const {
	return 0;
}

Vector3 LightStorage::reflection_probe_get_size(RID p_probe) const {
	return Vector3();
}

Vector3 LightStorage::reflection_probe_get_origin_offset(RID p_probe) const {
	return Vector3();
}

float LightStorage::reflection_probe_get_origin_max_distance(RID p_probe) const {
	return 0.0;
}

bool LightStorage::reflection_probe_renders_shadows(RID p_probe) const {
	return false;
}

void LightStorage::reflection_probe_set_mesh_lod_threshold(RID p_probe, float p_ratio) {
}

float LightStorage::reflection_probe_get_mesh_lod_threshold(RID p_probe) const {
	return 0.0;
}

/* REFLECTION ATLAS */

RID LightStorage::reflection_atlas_create() {
	return RID();
}

void LightStorage::reflection_atlas_free(RID p_ref_atlas) {
}

int LightStorage::reflection_atlas_get_size(RID p_ref_atlas) const {
	return 0;
}

void LightStorage::reflection_atlas_set_size(RID p_ref_atlas, int p_reflection_size, int p_reflection_count) {
}

/* REFLECTION PROBE INSTANCE */

RID LightStorage::reflection_probe_instance_create(RID p_probe) {
	return RID();
}

void LightStorage::reflection_probe_instance_free(RID p_instance) {
}

void LightStorage::reflection_probe_instance_set_transform(RID p_instance, const Transform3D &p_transform) {
}

void LightStorage::reflection_probe_release_atlas_index(RID p_instance) {
}

bool LightStorage::reflection_probe_instance_needs_redraw(RID p_instance) {
	return false;
}

bool LightStorage::reflection_probe_instance_has_reflection(RID p_instance) {
	return false;
}

bool LightStorage::reflection_probe_instance_begin_render(RID p_instance, RID p_reflection_atlas) {
	return false;
}

Ref<RenderSceneBuffers> LightStorage::reflection_probe_atlas_get_render_buffers(RID p_reflection_atlas) {
	return Ref<RenderSceneBuffers>();
}

bool LightStorage::reflection_probe_instance_postprocess_step(RID p_instance) {
	return true;
}

/* LIGHTMAP CAPTURE */

RID LightStorage::lightmap_allocate() {
	return lightmap_owner.allocate_rid();
}

void LightStorage::lightmap_initialize(RID p_rid) {
	lightmap_owner.initialize_rid(p_rid, Lightmap());
}

void LightStorage::lightmap_free(RID p_rid) {
	Lightmap *lightmap = lightmap_owner.get_or_null(p_rid);
	lightmap->dependency.deleted_notify(p_rid);
	lightmap_owner.free(p_rid);
}

void LightStorage::lightmap_set_textures(RID p_lightmap, RID p_light, bool p_uses_spherical_haromics) {
}

void LightStorage::lightmap_set_probe_bounds(RID p_lightmap, const AABB &p_bounds) {
}

void LightStorage::lightmap_set_probe_interior(RID p_lightmap, bool p_interior) {
}

void LightStorage::lightmap_set_probe_capture_data(RID p_lightmap, const PackedVector3Array &p_points, const PackedColorArray &p_point_sh, const PackedInt32Array &p_tetrahedra, const PackedInt32Array &p_bsp_tree) {
}

void LightStorage::lightmap_set_baked_exposure_normalization(RID p_lightmap, float p_exposure) {
}

PackedVector3Array LightStorage::lightmap_get_probe_capture_points(RID p_lightmap) const {
	return PackedVector3Array();
}

PackedColorArray LightStorage::lightmap_get_probe_capture_sh(RID p_lightmap) const {
	return PackedColorArray();
}

PackedInt32Array LightStorage::lightmap_get_probe_capture_tetrahedra(RID p_lightmap) const {
	return PackedInt32Array();
}

PackedInt32Array LightStorage::lightmap_get_probe_capture_bsp_tree(RID p_lightmap) const {
	return PackedInt32Array();
}

AABB LightStorage::lightmap_get_aabb(RID p_lightmap) const {
	return AABB();
}

void LightStorage::lightmap_tap_sh_light(RID p_lightmap, const Vector3 &p_point, Color *r_sh) {
}

bool LightStorage::lightmap_is_interior(RID p_lightmap) const {
	return false;
}

void LightStorage::lightmap_set_probe_capture_update_speed(float p_speed) {
}

float LightStorage::lightmap_get_probe_capture_update_speed() const {
	return 0;
}

/* LIGHTMAP INSTANCE */

RID LightStorage::lightmap_instance_create(RID p_lightmap) {
	return RID();
}

void LightStorage::lightmap_instance_free(RID p_lightmap) {
}

void LightStorage::lightmap_instance_set_transform(RID p_lightmap, const Transform3D &p_transform) {
}

/* SHADOW ATLAS API */

RID LightStorage::shadow_atlas_create() {
	return shadow_atlas_owner.make_rid(ShadowAtlas());
}

void LightStorage::shadow_atlas_free(RID p_atlas) {
	shadow_atlas_set_size(p_atlas, 0);
	shadow_atlas_owner.free(p_atlas);
}

void LightStorage::shadow_atlas_set_size(RID p_atlas, int p_size, bool p_16_bits) {
	ShadowAtlas *shadow_atlas = shadow_atlas_owner.get_or_null(p_atlas);
	ERR_FAIL_NULL(shadow_atlas);
	ERR_FAIL_COND(p_size < 0);
	p_size = next_power_of_2(p_size);

	if (p_size == shadow_atlas->size && p_16_bits == shadow_atlas->use_16_bits) {
		return;
	}

	for (uint32_t i = 0; i < 4; i++) {
		// Clear all subdivisions and free shadows.
		for (uint32_t j = 0; j < shadow_atlas->quadrants[i].textures.size(); j++) {
			glDeleteTextures(1, &shadow_atlas->quadrants[i].textures[j]);
			glDeleteFramebuffers(1, &shadow_atlas->quadrants[i].fbos[j]);
		}
		shadow_atlas->quadrants[i].textures.clear();
		shadow_atlas->quadrants[i].fbos.clear();

		shadow_atlas->quadrants[i].shadows.clear();
		shadow_atlas->quadrants[i].shadows.resize(shadow_atlas->quadrants[i].subdivision * shadow_atlas->quadrants[i].subdivision);
	}

	// Erase shadow atlas reference from lights.
	for (const KeyValue<RID, uint32_t> &E : shadow_atlas->shadow_owners) {
		LightInstance *li = light_instance_owner.get_or_null(E.key);
		ERR_CONTINUE(!li);
		li->shadow_atlases.erase(p_atlas);
	}

	if (shadow_atlas->debug_texture != 0) {
		glDeleteTextures(1, &shadow_atlas->debug_texture);
	}

	if (shadow_atlas->debug_fbo != 0) {
		glDeleteFramebuffers(1, &shadow_atlas->debug_fbo);
	}

	// Clear owners.
	shadow_atlas->shadow_owners.clear();

	shadow_atlas->size = p_size;
	shadow_atlas->use_16_bits = p_16_bits;
}

void LightStorage::shadow_atlas_set_quadrant_subdivision(RID p_atlas, int p_quadrant, int p_subdivision) {
	ShadowAtlas *shadow_atlas = shadow_atlas_owner.get_or_null(p_atlas);
	ERR_FAIL_NULL(shadow_atlas);
	ERR_FAIL_INDEX(p_quadrant, 4);
	ERR_FAIL_INDEX(p_subdivision, 16384);

	uint32_t subdiv = next_power_of_2(p_subdivision);
	if (subdiv & 0xaaaaaaaa) { // sqrt(subdiv) must be integer.
		subdiv <<= 1;
	}

	subdiv = int(Math::sqrt((float)subdiv));

	if (shadow_atlas->quadrants[p_quadrant].subdivision == subdiv) {
		return;
	}

	// Erase all data from quadrant.
	for (int i = 0; i < shadow_atlas->quadrants[p_quadrant].shadows.size(); i++) {
		if (shadow_atlas->quadrants[p_quadrant].shadows[i].owner.is_valid()) {
			shadow_atlas->shadow_owners.erase(shadow_atlas->quadrants[p_quadrant].shadows[i].owner);
			LightInstance *li = light_instance_owner.get_or_null(shadow_atlas->quadrants[p_quadrant].shadows[i].owner);
			ERR_CONTINUE(!li);
			li->shadow_atlases.erase(p_atlas);
		}
	}

	for (uint32_t j = 0; j < shadow_atlas->quadrants[p_quadrant].textures.size(); j++) {
		glDeleteTextures(1, &shadow_atlas->quadrants[p_quadrant].textures[j]);
		glDeleteFramebuffers(1, &shadow_atlas->quadrants[p_quadrant].fbos[j]);
	}

	shadow_atlas->quadrants[p_quadrant].textures.clear();
	shadow_atlas->quadrants[p_quadrant].fbos.clear();

	shadow_atlas->quadrants[p_quadrant].shadows.clear();
	shadow_atlas->quadrants[p_quadrant].shadows.resize(subdiv * subdiv);
	shadow_atlas->quadrants[p_quadrant].subdivision = subdiv;

	// Cache the smallest subdiv (for faster allocation in light update).

	shadow_atlas->smallest_subdiv = 1 << 30;

	for (int i = 0; i < 4; i++) {
		if (shadow_atlas->quadrants[i].subdivision) {
			shadow_atlas->smallest_subdiv = MIN(shadow_atlas->smallest_subdiv, shadow_atlas->quadrants[i].subdivision);
		}
	}

	if (shadow_atlas->smallest_subdiv == 1 << 30) {
		shadow_atlas->smallest_subdiv = 0;
	}

	// Re-sort the size orders, simple bubblesort for 4 elements.

	int swaps = 0;
	do {
		swaps = 0;

		for (int i = 0; i < 3; i++) {
			if (shadow_atlas->quadrants[shadow_atlas->size_order[i]].subdivision < shadow_atlas->quadrants[shadow_atlas->size_order[i + 1]].subdivision) {
				SWAP(shadow_atlas->size_order[i], shadow_atlas->size_order[i + 1]);
				swaps++;
			}
		}
	} while (swaps > 0);
}

bool LightStorage::shadow_atlas_update_light(RID p_atlas, RID p_light_instance, float p_coverage, uint64_t p_light_version) {
	ShadowAtlas *shadow_atlas = shadow_atlas_owner.get_or_null(p_atlas);
	ERR_FAIL_NULL_V(shadow_atlas, false);

	LightInstance *li = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL_V(li, false);

	if (shadow_atlas->size == 0 || shadow_atlas->smallest_subdiv == 0) {
		return false;
	}

	uint32_t quad_size = shadow_atlas->size >> 1;
	int desired_fit = MIN(quad_size / shadow_atlas->smallest_subdiv, next_power_of_2(quad_size * p_coverage));

	int valid_quadrants[4];
	int valid_quadrant_count = 0;
	int best_size = -1; // Best size found.
	int best_subdiv = -1; // Subdiv for the best size.

	// Find the quadrants this fits into, and the best possible size it can fit into.
	for (int i = 0; i < 4; i++) {
		int q = shadow_atlas->size_order[i];
		int sd = shadow_atlas->quadrants[q].subdivision;
		if (sd == 0) {
			continue; // Unused.
		}

		int max_fit = quad_size / sd;

		if (best_size != -1 && max_fit > best_size) {
			break; // Too large.
		}

		valid_quadrants[valid_quadrant_count++] = q;
		best_subdiv = sd;

		if (max_fit >= desired_fit) {
			best_size = max_fit;
		}
	}

	ERR_FAIL_COND_V(valid_quadrant_count == 0, false);

	uint64_t tick = OS::get_singleton()->get_ticks_msec();

	uint32_t old_key = SHADOW_INVALID;
	uint32_t old_quadrant = SHADOW_INVALID;
	uint32_t old_shadow = SHADOW_INVALID;
	int old_subdivision = -1;

	bool should_realloc = false;
	bool should_redraw = false;

	if (shadow_atlas->shadow_owners.has(p_light_instance)) {
		old_key = shadow_atlas->shadow_owners[p_light_instance];
		old_quadrant = (old_key >> QUADRANT_SHIFT) & 0x3;
		old_shadow = old_key & SHADOW_INDEX_MASK;

		// Only re-allocate if a better option is available, and enough time has passed.
		should_realloc = shadow_atlas->quadrants[old_quadrant].subdivision != (uint32_t)best_subdiv && (shadow_atlas->quadrants[old_quadrant].shadows[old_shadow].alloc_tick - tick > shadow_atlas_realloc_tolerance_msec);
		should_redraw = shadow_atlas->quadrants[old_quadrant].shadows[old_shadow].version != p_light_version;

		if (!should_realloc) {
			shadow_atlas->quadrants[old_quadrant].shadows.write[old_shadow].version = p_light_version;
			// Already existing, see if it should redraw or it's just OK.
			return should_redraw;
		}

		old_subdivision = shadow_atlas->quadrants[old_quadrant].subdivision;
	}

	bool is_omni = li->light_type == RS::LIGHT_OMNI;
	bool found_shadow = false;
	int new_quadrant = -1;
	int new_shadow = -1;

	found_shadow = _shadow_atlas_find_shadow(shadow_atlas, valid_quadrants, valid_quadrant_count, old_subdivision, tick, is_omni, new_quadrant, new_shadow);

	// For new shadows if we found an atlas.
	// Or for existing shadows that found a better atlas.
	if (found_shadow) {
		if (old_quadrant != SHADOW_INVALID) {
			shadow_atlas->quadrants[old_quadrant].shadows.write[old_shadow].version = 0;
			shadow_atlas->quadrants[old_quadrant].shadows.write[old_shadow].owner = RID();
		}

		uint32_t new_key = new_quadrant << QUADRANT_SHIFT;
		new_key |= new_shadow;

		ShadowAtlas::Quadrant::Shadow *sh = &shadow_atlas->quadrants[new_quadrant].shadows.write[new_shadow];
		_shadow_atlas_invalidate_shadow(sh, p_atlas, shadow_atlas, new_quadrant, new_shadow);

		sh->owner = p_light_instance;
		sh->owner_is_omni = is_omni;
		sh->alloc_tick = tick;
		sh->version = p_light_version;

		li->shadow_atlases.insert(p_atlas);

		// Update it in map.
		shadow_atlas->shadow_owners[p_light_instance] = new_key;
		// Make it dirty, as it should redraw anyway.
		return true;
	}

	return should_redraw;
}

bool LightStorage::_shadow_atlas_find_shadow(ShadowAtlas *shadow_atlas, int *p_in_quadrants, int p_quadrant_count, int p_current_subdiv, uint64_t p_tick, bool is_omni, int &r_quadrant, int &r_shadow) {
	for (int i = p_quadrant_count - 1; i >= 0; i--) {
		int qidx = p_in_quadrants[i];

		if (shadow_atlas->quadrants[qidx].subdivision == (uint32_t)p_current_subdiv) {
			return false;
		}

		// Look for an empty space.
		int sc = shadow_atlas->quadrants[qidx].shadows.size();
		const ShadowAtlas::Quadrant::Shadow *sarr = shadow_atlas->quadrants[qidx].shadows.ptr();

		// We have a free space in this quadrant, allocate a texture and use it.
		if (sc > (int)shadow_atlas->quadrants[qidx].textures.size()) {
			GLuint fbo_id = 0;
			glGenFramebuffers(1, &fbo_id);
			glBindFramebuffer(GL_FRAMEBUFFER, fbo_id);

			GLuint texture_id = 0;
			glGenTextures(1, &texture_id);
			glActiveTexture(GL_TEXTURE0);

			int size = (shadow_atlas->size >> 1) / shadow_atlas->quadrants[qidx].subdivision;

			GLenum format = shadow_atlas->use_16_bits ? GL_DEPTH_COMPONENT16 : GL_DEPTH_COMPONENT24;
			GLenum type = shadow_atlas->use_16_bits ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;

			if (is_omni) {
				glBindTexture(GL_TEXTURE_CUBE_MAP, texture_id);
				for (int id = 0; id < 6; id++) {
					glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + id, 0, format, size / 2, size / 2, 0, GL_DEPTH_COMPONENT, type, nullptr);
				}

				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
				glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_COMPARE_FUNC, GL_LESS);

				glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_CUBE_MAP_POSITIVE_X, texture_id, 0);

#ifdef DEBUG_ENABLED
				GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
				if (status != GL_FRAMEBUFFER_COMPLETE) {
					ERR_PRINT("Could not create omni light shadow framebuffer, status: " + GLES3::TextureStorage::get_singleton()->get_framebuffer_error(status));
				}
#endif
				glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
			} else {
				glBindTexture(GL_TEXTURE_2D, texture_id);

				glTexImage2D(GL_TEXTURE_2D, 0, format, size, size, 0, GL_DEPTH_COMPONENT, type, nullptr);

				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);

				glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, texture_id, 0);

				glBindTexture(GL_TEXTURE_2D, 0);
			}
			glBindFramebuffer(GL_FRAMEBUFFER, 0);

			r_quadrant = qidx;
			r_shadow = shadow_atlas->quadrants[qidx].textures.size();

			shadow_atlas->quadrants[qidx].textures.push_back(texture_id);
			shadow_atlas->quadrants[qidx].fbos.push_back(fbo_id);

			return true;
		}

		int found_used_idx = -1; // Found existing one, must steal it.
		uint64_t min_pass = 0; // Pass of the existing one, try to use the least recently used one (LRU fashion).

		for (int j = 0; j < sc; j++) {
			LightInstance *sli = light_instance_owner.get_or_null(sarr[j].owner);
			ERR_CONTINUE(!sli);

			if (sli->last_scene_pass != RasterizerSceneGLES3::get_singleton()->get_scene_pass()) {
				// Was just allocated, don't kill it so soon, wait a bit.
				if (p_tick - sarr[j].alloc_tick < shadow_atlas_realloc_tolerance_msec) {
					continue;
				}

				if (found_used_idx == -1 || sli->last_scene_pass < min_pass) {
					found_used_idx = j;
					min_pass = sli->last_scene_pass;
				}
			}
		}

		if (found_used_idx != -1) {
			r_quadrant = qidx;
			r_shadow = found_used_idx;

			return true;
		}
	}

	return false;
}

void LightStorage::_shadow_atlas_invalidate_shadow(ShadowAtlas::Quadrant::Shadow *p_shadow, RID p_atlas, ShadowAtlas *p_shadow_atlas, uint32_t p_quadrant, uint32_t p_shadow_idx) {
	if (p_shadow->owner.is_valid()) {
		LightInstance *sli = light_instance_owner.get_or_null(p_shadow->owner);

		p_shadow_atlas->shadow_owners.erase(p_shadow->owner);
		p_shadow->version = 0;
		p_shadow->owner = RID();
		sli->shadow_atlases.erase(p_atlas);
	}
}

void LightStorage::shadow_atlas_update(RID p_atlas) {
	// Do nothing as there is no shadow atlas texture.
}

/* DIRECTIONAL SHADOW */

// Create if necessary and clear.
void LightStorage::update_directional_shadow_atlas() {
	if (directional_shadow.depth == 0 && directional_shadow.size > 0) {
		glGenFramebuffers(1, &directional_shadow.fbo);
		glBindFramebuffer(GL_FRAMEBUFFER, directional_shadow.fbo);

		glGenTextures(1, &directional_shadow.depth);
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, directional_shadow.depth);

		GLenum format = directional_shadow.use_16_bits ? GL_DEPTH_COMPONENT16 : GL_DEPTH_COMPONENT24;
		GLenum type = directional_shadow.use_16_bits ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;

		glTexImage2D(GL_TEXTURE_2D, 0, format, directional_shadow.size, directional_shadow.size, 0, GL_DEPTH_COMPONENT, type, nullptr);

		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);

		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, directional_shadow.depth, 0);
	}
	glDepthMask(GL_TRUE);
	glBindFramebuffer(GL_FRAMEBUFFER, directional_shadow.fbo);
	RasterizerGLES3::clear_depth(1.0);
	glClear(GL_DEPTH_BUFFER_BIT);

	glBindTexture(GL_TEXTURE_2D, 0);
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void LightStorage::directional_shadow_atlas_set_size(int p_size, bool p_16_bits) {
	p_size = nearest_power_of_2_templated(p_size);

	if (directional_shadow.size == p_size && directional_shadow.use_16_bits == p_16_bits) {
		return;
	}

	directional_shadow.size = p_size;
	directional_shadow.use_16_bits = p_16_bits;

	if (directional_shadow.depth != 0) {
		glDeleteTextures(1, &directional_shadow.depth);
		directional_shadow.depth = 0;
		glDeleteFramebuffers(1, &directional_shadow.fbo);
		directional_shadow.fbo = 0;
	}
}

void LightStorage::set_directional_shadow_count(int p_count) {
	directional_shadow.light_count = p_count;
	directional_shadow.current_light = 0;
}

static Rect2i _get_directional_shadow_rect(int p_size, int p_shadow_count, int p_shadow_index) {
	int split_h = 1;
	int split_v = 1;

	while (split_h * split_v < p_shadow_count) {
		if (split_h == split_v) {
			split_h <<= 1;
		} else {
			split_v <<= 1;
		}
	}

	Rect2i rect(0, 0, p_size, p_size);
	rect.size.width /= split_h;
	rect.size.height /= split_v;

	rect.position.x = rect.size.width * (p_shadow_index % split_h);
	rect.position.y = rect.size.height * (p_shadow_index / split_h);

	return rect;
}

Rect2i LightStorage::get_directional_shadow_rect() {
	return _get_directional_shadow_rect(directional_shadow.size, directional_shadow.light_count, directional_shadow.current_light);
}

int LightStorage::get_directional_light_shadow_size(RID p_light_instance) {
	ERR_FAIL_COND_V(directional_shadow.light_count == 0, 0);

	Rect2i r = _get_directional_shadow_rect(directional_shadow.size, directional_shadow.light_count, 0);

	LightInstance *light_instance = light_instance_owner.get_or_null(p_light_instance);
	ERR_FAIL_NULL_V(light_instance, 0);

	switch (light_directional_get_shadow_mode(light_instance->light)) {
		case RS::LIGHT_DIRECTIONAL_SHADOW_ORTHOGONAL:
			break; //none
		case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS:
			r.size.height /= 2;
			break;
		case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS:
			r.size /= 2;
			break;
	}

	return MAX(r.size.width, r.size.height);
}

#endif // !GLES3_ENABLED