basisu_frontend.h - external/github.com/BinomialLLC/basis_universal - Git at Google

 // basisu_frontend.h
 // Copyright (C) 2019-2020 Binomial LLC. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 #pragma once
 #include "basisu_enc.h"
 #include "basisu_etc.h"
 #include "basisu_gpu_texture.h"
 #include "basisu_global_selector_palette_helpers.h"
 #include "transcoder/basisu_file_headers.h"

 namespace basisu
 {
 	struct vec2U
 	{
 		uint32_t m_comps[2];

 		vec2U() { }
 		vec2U(uint32_t a, uint32_t b) { set(a, b); }

 		void set(uint32_t a, uint32_t b) { m_comps[0] = a; m_comps[1] = b; }

 		uint32_t operator[] (uint32_t i) const { assert(i < 2); return m_comps[i]; }
 		uint32_t &operator[] (uint32_t i) { assert(i < 2); return m_comps[i]; }
 	};

 	const uint32_t BASISU_DEFAULT_COMPRESSION_LEVEL = 1;
 	const uint32_t BASISU_MAX_COMPRESSION_LEVEL = 5;

 	class basisu_frontend
 	{
 		BASISU_NO_EQUALS_OR_COPY_CONSTRUCT(basisu_frontend);

 	public:

 		basisu_frontend() :
 			m_total_blocks(0),
 			m_total_pixels(0),
 			m_endpoint_refinement(false),
 			m_use_hierarchical_endpoint_codebooks(false),
 			m_use_hierarchical_selector_codebooks(false),
 			m_num_endpoint_codebook_iterations(0),
 			m_num_selector_codebook_iterations(0)
 		{
 		}

 		enum
 		{
 			cMaxEndpointClusters = 16128,

 			cMaxSelectorClusters = 16128,
 		};

 		struct params
 		{
 			params() :
 				m_num_source_blocks(0),
 				m_pSource_blocks(NULL),
 				m_max_endpoint_clusters(256),
 				m_max_selector_clusters(256),
 				m_compression_level(BASISU_DEFAULT_COMPRESSION_LEVEL),
 				m_perceptual(true),
 				m_debug_stats(false),
 				m_debug_images(false),

 				m_dump_endpoint_clusterization(true),
 				m_validate(false),
 				m_multithreaded(false),
 				m_disable_hierarchical_endpoint_codebooks(false),
 				m_pGlobal_sel_codebook(NULL),
 				m_num_global_sel_codebook_pal_bits(0),
 				m_num_global_sel_codebook_mod_bits(0),
 				m_use_hybrid_selector_codebooks(false),
 				m_hybrid_codebook_quality_thresh(0.0f),
 				m_tex_type(basist::cBASISTexType2D),

 				m_pJob_pool(nullptr)
 			{
 			}

 			uint32_t m_num_source_blocks;
 			pixel_block *m_pSource_blocks;

 			uint32_t m_max_endpoint_clusters;
 			uint32_t m_max_selector_clusters;

 			uint32_t m_compression_level;

 			bool m_perceptual;
 			bool m_debug_stats;
 			bool m_debug_images;
 			bool m_dump_endpoint_clusterization;
 			bool m_validate;
 			bool m_multithreaded;
 			bool m_disable_hierarchical_endpoint_codebooks;

 			const basist::etc1_global_selector_codebook *m_pGlobal_sel_codebook;
 			uint32_t m_num_global_sel_codebook_pal_bits;
 			uint32_t m_num_global_sel_codebook_mod_bits;
 			bool m_use_hybrid_selector_codebooks;
 			float m_hybrid_codebook_quality_thresh;
 			basist::basis_texture_type m_tex_type;

 			job_pool *m_pJob_pool;
 		};

 		bool init(const params &p);

 		bool compress();

 		const params &get_params() const { return m_params; }

 		const pixel_block &get_source_pixel_block(uint32_t i) const { return m_source_blocks[i]; }

 		// RDO output blocks
 		uint32_t get_total_output_blocks() const { return static_cast<uint32_t>(m_encoded_blocks.size()); }

 		const etc_block &get_output_block(uint32_t block_index) const { return m_encoded_blocks[block_index]; }
 		const etc_block_vec &get_output_blocks() const { return m_encoded_blocks; }

 		// "Best" ETC1S blocks
 		const etc_block &get_etc1s_block(uint32_t block_index) const { return m_etc1_blocks_etc1s[block_index]; }

 		// Per-block flags
 		bool get_diff_flag(uint32_t block_index) const { return m_encoded_blocks[block_index].get_diff_bit(); }

 		// Endpoint clusters
 		uint32_t get_total_endpoint_clusters() const { return static_cast<uint32_t>(m_endpoint_clusters.size()); }
 		uint32_t get_subblock_endpoint_cluster_index(uint32_t block_index, uint32_t subblock_index) const { return m_block_endpoint_clusters_indices[block_index][subblock_index]; }

 		const color_rgba &get_endpoint_cluster_unscaled_color(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_color_unscaled[individual_mode]; }
 		uint32_t get_endpoint_cluster_inten_table(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_inten_table[individual_mode]; }

 		bool get_endpoint_cluster_color_is_used(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_color_used[individual_mode]; }

 		// Selector clusters
 		uint32_t get_total_selector_clusters() const { return static_cast<uint32_t>(m_selector_cluster_indices.size()); }
 		uint32_t get_block_selector_cluster_index(uint32_t block_index) const { return m_block_selector_cluster_index[block_index]; }
 		const etc_block &get_selector_cluster_selector_bits(uint32_t cluster_index) const { return m_optimized_cluster_selectors[cluster_index]; }

 		const basist::etc1_global_selector_codebook_entry_id_vec &get_selector_cluster_global_selector_entry_ids() const { return m_optimized_cluster_selector_global_cb_ids; }
 		const bool_vec &get_selector_cluster_uses_global_cb_vec() const { return m_selector_cluster_uses_global_cb; }

 		// Returns block indices using each selector cluster
 		const uint_vec &get_selector_cluster_block_indices(uint32_t selector_cluster_index) const { return m_selector_cluster_indices[selector_cluster_index]; }

 		void dump_debug_image(const char *pFilename, uint32_t first_block, uint32_t num_blocks_x, uint32_t num_blocks_y, bool output_blocks);

 		void reoptimize_remapped_endpoints(const uint_vec &new_block_endpoints, int_vec &old_to_new_endpoint_cluster_indices, bool optimize_final_codebook, uint_vec *pBlock_selector_indices = nullptr);

 	private:
 		params m_params;
 		uint32_t m_total_blocks;
 		uint32_t m_total_pixels;

 		bool m_endpoint_refinement;
 		bool m_use_hierarchical_endpoint_codebooks;
 		bool m_use_hierarchical_selector_codebooks;

 		uint32_t m_num_endpoint_codebook_iterations;
 		uint32_t m_num_selector_codebook_iterations;

 		// Source pixels for each blocks
 		pixel_block_vec m_source_blocks;

 		// The quantized ETC1S texture.
 		etc_block_vec m_encoded_blocks;

 		// Quantized blocks after endpoint quant, but before selector quant
 		etc_block_vec m_orig_encoded_blocks;

 		// Full quality ETC1S texture
 		etc_block_vec m_etc1_blocks_etc1s;

 		typedef vec<6, float> vec6F;

 		// Endpoint clusterizer
 		typedef tree_vector_quant<vec6F> vec6F_quantizer;
 		vec6F_quantizer m_endpoint_clusterizer;

 		// For each endpoint cluster: An array of which subblock indices (block_index*2+subblock) are located in that cluster.
 		// Array of block indices for each endpoint cluster
 		std::vector<uint_vec> m_endpoint_clusters;

 		// Array of block indices for each parent endpoint cluster
 		std::vector<uint_vec> m_endpoint_parent_clusters;

 		// Each block's parent cluster index
 		uint8_vec m_block_parent_endpoint_cluster;

 		// Array of endpoint cluster indices for each parent endpoint cluster
 		std::vector<uint_vec> m_endpoint_clusters_within_each_parent_cluster;

 		struct endpoint_cluster_etc_params
 		{
 			endpoint_cluster_etc_params()
 			{
 				clear();
 			}

 			void clear()
 			{
 				clear_obj(m_color_unscaled);
 				clear_obj(m_inten_table);
 				clear_obj(m_color_error);
 				m_subblocks.clear();

 				clear_obj(m_color_used);
 				m_valid = false;
 			}

 			// TODO: basisu doesn't use individual mode.
 			color_rgba m_color_unscaled[2]; // [use_individual_mode]
 			uint32_t m_inten_table[2];

 			uint64_t m_color_error[2];

 			uint_vec m_subblocks;

 			bool m_color_used[2];

 			bool m_valid;

 			bool operator== (const endpoint_cluster_etc_params &other) const
 			{
 				for (uint32_t i = 0; i < 2; i++)
 				{
 					if (m_color_unscaled[i] != other.m_color_unscaled[i])
 						return false;
 				}

 				if (m_inten_table[0] != other.m_inten_table[0])
 					return false;
 				if (m_inten_table[1] != other.m_inten_table[1])
 					return false;

 				return true;
 			}

 			bool operator< (const endpoint_cluster_etc_params &other) const
 			{
 				for (uint32_t i = 0; i < 2; i++)
 				{
 					if (m_color_unscaled[i] < other.m_color_unscaled[i])
 						return true;
 					else if (m_color_unscaled[i] != other.m_color_unscaled[i])
 						return false;
 				}

 				if (m_inten_table[0] < other.m_inten_table[0])
 					return true;
 				else if (m_inten_table[0] == other.m_inten_table[0])
 				{
 					if (m_inten_table[1] < other.m_inten_table[1])
 						return true;
 				}

 				return false;
 			}
 		};

 		typedef std::vector<endpoint_cluster_etc_params> cluster_subblock_etc_params_vec;

 		// Each endpoint cluster's ETC1S parameters
 		cluster_subblock_etc_params_vec m_endpoint_cluster_etc_params;

 		// The endpoint cluster index used by each ETC1 subblock.
 		std::vector<vec2U> m_block_endpoint_clusters_indices;

 		// The block(s) within each selector cluster
 		// Note: If you add anything here that uses selector cluster indicies, be sure to update optimize_selector_codebook()!
 		std::vector<uint_vec> m_selector_cluster_indices;

 		// The selector bits for each selector cluster.
 		std::vector<etc_block> m_optimized_cluster_selectors;

 		// The block(s) within each parent selector cluster.
 		std::vector<uint_vec> m_selector_parent_cluster_indices;

 		// Each block's parent selector cluster
 		uint8_vec m_block_parent_selector_cluster;

 		// Array of selector cluster indices for each parent selector cluster
 		std::vector<uint_vec> m_selector_clusters_within_each_parent_cluster;

 		basist::etc1_global_selector_codebook_entry_id_vec m_optimized_cluster_selector_global_cb_ids;
 		bool_vec m_selector_cluster_uses_global_cb;

 		// Each block's selector cluster index
 		std::vector<uint32_t> m_block_selector_cluster_index;

 		struct subblock_endpoint_quant_err
 		{
 			uint64_t m_total_err;
 			uint32_t m_cluster_index;
 			uint32_t m_cluster_subblock_index;
 			uint32_t m_block_index;
 			uint32_t m_subblock_index;

 			bool operator< (const subblock_endpoint_quant_err &rhs) const
 			{
 				if (m_total_err < rhs.m_total_err)
 					return true;
 				else if (m_total_err == rhs.m_total_err)
 				{
 					if (m_block_index < rhs.m_block_index)
 						return true;
 					else if (m_block_index == rhs.m_block_index)
 						return m_subblock_index < rhs.m_subblock_index;
 				}
 				return false;
 			}
 		};

 		// The sorted subblock endpoint quant error for each endpoint cluster
 		std::vector<subblock_endpoint_quant_err> m_subblock_endpoint_quant_err_vec;

 		std::mutex m_lock;

 		//-----------------------------------------------------------------------------

 		void init_etc1_images();
 		void init_endpoint_training_vectors();
 		void dump_endpoint_clusterization_visualization(const char *pFilename, bool vis_endpoint_colors);
 		void generate_endpoint_clusters();
 		void compute_endpoint_subblock_error_vec();
 		void introduce_new_endpoint_clusters();
 		void generate_endpoint_codebook(uint32_t step);
 		uint32_t refine_endpoint_clusterization();
 		void eliminate_redundant_or_empty_endpoint_clusters();
 		void generate_block_endpoint_clusters();
 		void compute_endpoint_clusters_within_each_parent_cluster();
 		void compute_selector_clusters_within_each_parent_cluster();
 		void create_initial_packed_texture();
 		void generate_selector_clusters();
 		void create_optimized_selector_codebook(uint32_t iter);
 		void find_optimal_selector_clusters_for_each_block();
 		uint32_t refine_block_endpoints_given_selectors();
 		void finalize();
 		bool validate_output() const;
 		void introduce_special_selector_clusters();
 		void optimize_selector_codebook();
 		bool check_etc1s_constraints() const;
 	};

 } // namespace basisu
	// basisu_frontend.h
	// Copyright (C) 2019-2020 Binomial LLC. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	#pragma once
	#include "basisu_enc.h"
	#include "basisu_etc.h"
	#include "basisu_gpu_texture.h"
	#include "basisu_global_selector_palette_helpers.h"
	#include "transcoder/basisu_file_headers.h"

	namespace basisu
	{
	struct vec2U
	{
	uint32_t m_comps[2];

	vec2U() { }
	vec2U(uint32_t a, uint32_t b) { set(a, b); }

	void set(uint32_t a, uint32_t b) { m_comps[0] = a; m_comps[1] = b; }

	uint32_t operator[] (uint32_t i) const { assert(i < 2); return m_comps[i]; }
	uint32_t &operator[] (uint32_t i) { assert(i < 2); return m_comps[i]; }
	};

	const uint32_t BASISU_DEFAULT_COMPRESSION_LEVEL = 1;
	const uint32_t BASISU_MAX_COMPRESSION_LEVEL = 5;

	class basisu_frontend
	{
	BASISU_NO_EQUALS_OR_COPY_CONSTRUCT(basisu_frontend);

	public:

	basisu_frontend() :
	m_total_blocks(0),
	m_total_pixels(0),
	m_endpoint_refinement(false),
	m_use_hierarchical_endpoint_codebooks(false),
	m_use_hierarchical_selector_codebooks(false),
	m_num_endpoint_codebook_iterations(0),
	m_num_selector_codebook_iterations(0)
	{
	}

	enum
	{
	cMaxEndpointClusters = 16128,

	cMaxSelectorClusters = 16128,
	};

	struct params
	{
	params() :
	m_num_source_blocks(0),
	m_pSource_blocks(NULL),
	m_max_endpoint_clusters(256),
	m_max_selector_clusters(256),
	m_compression_level(BASISU_DEFAULT_COMPRESSION_LEVEL),
	m_perceptual(true),
	m_debug_stats(false),
	m_debug_images(false),

	m_dump_endpoint_clusterization(true),
	m_validate(false),
	m_multithreaded(false),
	m_disable_hierarchical_endpoint_codebooks(false),
	m_pGlobal_sel_codebook(NULL),
	m_num_global_sel_codebook_pal_bits(0),
	m_num_global_sel_codebook_mod_bits(0),
	m_use_hybrid_selector_codebooks(false),
	m_hybrid_codebook_quality_thresh(0.0f),
	m_tex_type(basist::cBASISTexType2D),

	m_pJob_pool(nullptr)
	{
	}

	uint32_t m_num_source_blocks;
	pixel_block *m_pSource_blocks;

	uint32_t m_max_endpoint_clusters;
	uint32_t m_max_selector_clusters;

	uint32_t m_compression_level;

	bool m_perceptual;
	bool m_debug_stats;
	bool m_debug_images;
	bool m_dump_endpoint_clusterization;
	bool m_validate;
	bool m_multithreaded;
	bool m_disable_hierarchical_endpoint_codebooks;

	const basist::etc1_global_selector_codebook *m_pGlobal_sel_codebook;
	uint32_t m_num_global_sel_codebook_pal_bits;
	uint32_t m_num_global_sel_codebook_mod_bits;
	bool m_use_hybrid_selector_codebooks;
	float m_hybrid_codebook_quality_thresh;
	basist::basis_texture_type m_tex_type;

	job_pool *m_pJob_pool;
	};

	bool init(const params &p);

	bool compress();

	const params &get_params() const { return m_params; }

	const pixel_block &get_source_pixel_block(uint32_t i) const { return m_source_blocks[i]; }

	// RDO output blocks
	uint32_t get_total_output_blocks() const { return static_cast<uint32_t>(m_encoded_blocks.size()); }

	const etc_block &get_output_block(uint32_t block_index) const { return m_encoded_blocks[block_index]; }
	const etc_block_vec &get_output_blocks() const { return m_encoded_blocks; }

	// "Best" ETC1S blocks
	const etc_block &get_etc1s_block(uint32_t block_index) const { return m_etc1_blocks_etc1s[block_index]; }

	// Per-block flags
	bool get_diff_flag(uint32_t block_index) const { return m_encoded_blocks[block_index].get_diff_bit(); }

	// Endpoint clusters
	uint32_t get_total_endpoint_clusters() const { return static_cast<uint32_t>(m_endpoint_clusters.size()); }
	uint32_t get_subblock_endpoint_cluster_index(uint32_t block_index, uint32_t subblock_index) const { return m_block_endpoint_clusters_indices[block_index][subblock_index]; }

	const color_rgba &get_endpoint_cluster_unscaled_color(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_color_unscaled[individual_mode]; }
	uint32_t get_endpoint_cluster_inten_table(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_inten_table[individual_mode]; }

	bool get_endpoint_cluster_color_is_used(uint32_t cluster_index, bool individual_mode) const { return m_endpoint_cluster_etc_params[cluster_index].m_color_used[individual_mode]; }

	// Selector clusters
	uint32_t get_total_selector_clusters() const { return static_cast<uint32_t>(m_selector_cluster_indices.size()); }
	uint32_t get_block_selector_cluster_index(uint32_t block_index) const { return m_block_selector_cluster_index[block_index]; }
	const etc_block &get_selector_cluster_selector_bits(uint32_t cluster_index) const { return m_optimized_cluster_selectors[cluster_index]; }

	const basist::etc1_global_selector_codebook_entry_id_vec &get_selector_cluster_global_selector_entry_ids() const { return m_optimized_cluster_selector_global_cb_ids; }
	const bool_vec &get_selector_cluster_uses_global_cb_vec() const { return m_selector_cluster_uses_global_cb; }

	// Returns block indices using each selector cluster
	const uint_vec &get_selector_cluster_block_indices(uint32_t selector_cluster_index) const { return m_selector_cluster_indices[selector_cluster_index]; }

	void dump_debug_image(const char *pFilename, uint32_t first_block, uint32_t num_blocks_x, uint32_t num_blocks_y, bool output_blocks);

	void reoptimize_remapped_endpoints(const uint_vec &new_block_endpoints, int_vec &old_to_new_endpoint_cluster_indices, bool optimize_final_codebook, uint_vec *pBlock_selector_indices = nullptr);

	private:
	params m_params;
	uint32_t m_total_blocks;
	uint32_t m_total_pixels;

	bool m_endpoint_refinement;
	bool m_use_hierarchical_endpoint_codebooks;
	bool m_use_hierarchical_selector_codebooks;

	uint32_t m_num_endpoint_codebook_iterations;
	uint32_t m_num_selector_codebook_iterations;

	// Source pixels for each blocks
	pixel_block_vec m_source_blocks;

	// The quantized ETC1S texture.
	etc_block_vec m_encoded_blocks;

	// Quantized blocks after endpoint quant, but before selector quant
	etc_block_vec m_orig_encoded_blocks;

	// Full quality ETC1S texture
	etc_block_vec m_etc1_blocks_etc1s;

	typedef vec<6, float> vec6F;

	// Endpoint clusterizer
	typedef tree_vector_quant<vec6F> vec6F_quantizer;
	vec6F_quantizer m_endpoint_clusterizer;

	// For each endpoint cluster: An array of which subblock indices (block_index*2+subblock) are located in that cluster.
	// Array of block indices for each endpoint cluster
	std::vector<uint_vec> m_endpoint_clusters;

	// Array of block indices for each parent endpoint cluster
	std::vector<uint_vec> m_endpoint_parent_clusters;

	// Each block's parent cluster index
	uint8_vec m_block_parent_endpoint_cluster;

	// Array of endpoint cluster indices for each parent endpoint cluster
	std::vector<uint_vec> m_endpoint_clusters_within_each_parent_cluster;

	struct endpoint_cluster_etc_params
	{
	endpoint_cluster_etc_params()
	{
	clear();
	}

	void clear()
	{
	clear_obj(m_color_unscaled);
	clear_obj(m_inten_table);
	clear_obj(m_color_error);
	m_subblocks.clear();

	clear_obj(m_color_used);
	m_valid = false;
	}

	// TODO: basisu doesn't use individual mode.
	color_rgba m_color_unscaled[2]; // [use_individual_mode]
	uint32_t m_inten_table[2];

	uint64_t m_color_error[2];

	uint_vec m_subblocks;

	bool m_color_used[2];

	bool m_valid;

	bool operator== (const endpoint_cluster_etc_params &other) const
	{
	for (uint32_t i = 0; i < 2; i++)
	{
	if (m_color_unscaled[i] != other.m_color_unscaled[i])
	return false;
	}

	if (m_inten_table[0] != other.m_inten_table[0])
	return false;
	if (m_inten_table[1] != other.m_inten_table[1])
	return false;

	return true;
	}

	bool operator< (const endpoint_cluster_etc_params &other) const
	{
	for (uint32_t i = 0; i < 2; i++)
	{
	if (m_color_unscaled[i] < other.m_color_unscaled[i])
	return true;
	else if (m_color_unscaled[i] != other.m_color_unscaled[i])
	return false;
	}

	if (m_inten_table[0] < other.m_inten_table[0])
	return true;
	else if (m_inten_table[0] == other.m_inten_table[0])
	{
	if (m_inten_table[1] < other.m_inten_table[1])
	return true;
	}

	return false;
	}
	};

	typedef std::vector<endpoint_cluster_etc_params> cluster_subblock_etc_params_vec;

	// Each endpoint cluster's ETC1S parameters
	cluster_subblock_etc_params_vec m_endpoint_cluster_etc_params;

	// The endpoint cluster index used by each ETC1 subblock.
	std::vector<vec2U> m_block_endpoint_clusters_indices;

	// The block(s) within each selector cluster
	// Note: If you add anything here that uses selector cluster indicies, be sure to update optimize_selector_codebook()!
	std::vector<uint_vec> m_selector_cluster_indices;

	// The selector bits for each selector cluster.
	std::vector<etc_block> m_optimized_cluster_selectors;

	// The block(s) within each parent selector cluster.
	std::vector<uint_vec> m_selector_parent_cluster_indices;

	// Each block's parent selector cluster
	uint8_vec m_block_parent_selector_cluster;

	// Array of selector cluster indices for each parent selector cluster
	std::vector<uint_vec> m_selector_clusters_within_each_parent_cluster;

	basist::etc1_global_selector_codebook_entry_id_vec m_optimized_cluster_selector_global_cb_ids;
	bool_vec m_selector_cluster_uses_global_cb;

	// Each block's selector cluster index
	std::vector<uint32_t> m_block_selector_cluster_index;

	struct subblock_endpoint_quant_err
	{
	uint64_t m_total_err;
	uint32_t m_cluster_index;
	uint32_t m_cluster_subblock_index;
	uint32_t m_block_index;
	uint32_t m_subblock_index;

	bool operator< (const subblock_endpoint_quant_err &rhs) const
	{
	if (m_total_err < rhs.m_total_err)
	return true;
	else if (m_total_err == rhs.m_total_err)
	{
	if (m_block_index < rhs.m_block_index)
	return true;
	else if (m_block_index == rhs.m_block_index)
	return m_subblock_index < rhs.m_subblock_index;
	}
	return false;
	}
	};

	// The sorted subblock endpoint quant error for each endpoint cluster
	std::vector<subblock_endpoint_quant_err> m_subblock_endpoint_quant_err_vec;

	std::mutex m_lock;

	//-----------------------------------------------------------------------------

	void init_etc1_images();
	void init_endpoint_training_vectors();
	void dump_endpoint_clusterization_visualization(const char *pFilename, bool vis_endpoint_colors);
	void generate_endpoint_clusters();
	void compute_endpoint_subblock_error_vec();
	void introduce_new_endpoint_clusters();
	void generate_endpoint_codebook(uint32_t step);
	uint32_t refine_endpoint_clusterization();
	void eliminate_redundant_or_empty_endpoint_clusters();
	void generate_block_endpoint_clusters();
	void compute_endpoint_clusters_within_each_parent_cluster();
	void compute_selector_clusters_within_each_parent_cluster();
	void create_initial_packed_texture();
	void generate_selector_clusters();
	void create_optimized_selector_codebook(uint32_t iter);
	void find_optimal_selector_clusters_for_each_block();
	uint32_t refine_block_endpoints_given_selectors();
	void finalize();
	bool validate_output() const;
	void introduce_special_selector_clusters();
	void optimize_selector_codebook();
	bool check_etc1s_constraints() const;
	};

	} // namespace basisu