/**************************************************************************/
/*  voxelizer.h                                                           */
/**************************************************************************/
/*                         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.                  */
/*                                                                        */
/* 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.                 */
/**************************************************************************/

#ifndef VOXELIZER_H
#define VOXELIZER_H

#include "scene/resources/multimesh.h"

class Voxelizer {
public:
	enum BakeResult {
		BAKE_RESULT_OK,
		BAKE_RESULT_INVALID_PARAMETER,
		BAKE_RESULT_CANCELLED,
	};

	typedef bool (*BakeStepFunc)(int, int);

private:
	enum : uint32_t {
		CHILD_EMPTY = 0xFFFFFFFF
	};

	struct Cell {
		uint32_t children[8];
		float albedo[3] = {}; //albedo in RGB24
		float emission[3] = {}; //accumulated light in 16:16 fixed point (needs to be integer for moving lights fast)
		float normal[3] = {};
		uint32_t used_sides = 0;
		float alpha = 0.0; //used for upsampling
		uint16_t x = 0;
		uint16_t y = 0;
		uint16_t z = 0;
		uint16_t level = 0;

		Cell() {
			for (int i = 0; i < 8; i++) {
				children[i] = CHILD_EMPTY;
			}
		}
	};

	Vector<Cell> bake_cells;
	int cell_subdiv = 0;

	struct CellSort {
		union {
			struct {
				uint64_t z : 16;
				uint64_t y : 16;
				uint64_t x : 16;
				uint64_t level : 16;
			};
			uint64_t key = 0;
		};

		int32_t index = 0;

		_FORCE_INLINE_ bool operator<(const CellSort &p_cell_sort) const {
			return key < p_cell_sort.key;
		}
	};

	struct MaterialCache {
		//128x128 textures
		Vector<Color> albedo;
		Vector<Color> emission;
	};

	HashMap<Ref<Material>, MaterialCache> material_cache;
	float exposure_normalization = 1.0;
	AABB original_bounds;
	AABB po2_bounds;
	int axis_cell_size[3] = {};

	Transform3D to_cell_space;

	int color_scan_cell_width = 4;
	int bake_texture_size = 128;
	float cell_size = 0.0;

	int max_original_cells = 0;
	int leaf_voxel_count = 0;

	Vector<Color> _get_bake_texture(Ref<Image> p_image, const Color &p_color_mul, const Color &p_color_add);
	MaterialCache _get_material_cache(Ref<Material> p_material);

	void _plot_face(int p_idx, int p_level, int p_x, int p_y, int p_z, const Vector3 *p_vtx, const Vector3 *p_normal, const Vector2 *p_uv, const MaterialCache &p_material, const AABB &p_aabb);
	void _fixup_plot(int p_idx, int p_level);
	void _debug_mesh(int p_idx, int p_level, const AABB &p_aabb, Ref<MultiMesh> &p_multimesh, int &idx);

	bool sorted = false;
	void _sort();

public:
	void begin_bake(int p_subdiv, const AABB &p_bounds, float p_exposure_normalization);
	int get_bake_steps(Ref<Mesh> &p_mesh) const;
	BakeResult plot_mesh(const Transform3D &p_xform, Ref<Mesh> &p_mesh, const Vector<Ref<Material>> &p_materials, const Ref<Material> &p_override_material, BakeStepFunc p_bake_step_function);
	void end_bake();

	int get_voxel_gi_octree_depth() const;
	Vector3i get_voxel_gi_octree_size() const;
	int get_voxel_gi_cell_count() const;
	Vector<uint8_t> get_voxel_gi_octree_cells() const;
	Vector<uint8_t> get_voxel_gi_data_cells() const;
	Vector<int> get_voxel_gi_level_cell_count() const;
	BakeResult get_sdf_3d_image(Vector<uint8_t> &r_image, BakeStepFunc p_bake_step_function) const;

	Ref<MultiMesh> create_debug_multimesh();

	Transform3D get_to_cell_space_xform() const;
	Voxelizer();
};

#endif // VOXELIZER_H