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- // basisu_transcoder.h
- // Copyright (C) 2019 Binomial LLC. All Rights Reserved.
- // Important: If compiling with gcc, be sure strict aliasing is disabled: -fno-strict-aliasing
- //
- // 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
- // Set BASISU_DEVEL_MESSAGES to 1 to enable debug printf()'s whenever an error occurs, for easier debugging during development.
- //#define BASISU_DEVEL_MESSAGES 1
- #include "basisu_transcoder_internal.h"
- #include "basisu_global_selector_palette.h"
- #include "basisu_file_headers.h"
- namespace basist
- {
- // High-level composite texture formats supported by the transcoder.
- // Each of these texture formats directly correspond to OpenGL/D3D/Vulkan etc. texture formats.
- // Notes:
- // - If you specify a texture format that supports alpha, but the .basis file doesn't have alpha, the transcoder will automatically output a
- // fully opaque (255) alpha channel.
- // - The PVRTC1 texture formats only support power of 2 dimension .basis files, but this may be relaxed in a future version.
- // - The PVRTC1 transcoders are real-time encoders, so don't expect the highest quality. We may add a slower encoder with improved quality.
- enum transcoder_texture_format
- {
- // Compressed formats
- // ETC1-2
- cTFETC1, // Opaque only, returns RGB or alpha data if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
- cTFETC2, // Opaque+alpha, ETC2_EAC_A8 block followed by a ETC1 block, alpha channel will be opaque for opaque .basis files
- // BC1-5, BC7
- cTFBC1, // Opaque only, no punchthrough alpha support yet, transcodes alpha slice if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
- cTFBC3, // Opaque+alpha, BC4 followed by a BC1 block, alpha channel will be opaque for opaque .basis files
- cTFBC4, // Red only, alpha slice is transcoded to output if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
- cTFBC5, // XY: Two BC4 blocks, X=R and Y=Alpha, .basis file should have alpha data (if not Y will be all 255's)
- cTFBC7_M6_OPAQUE_ONLY, // Opaque only, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified. Highest quality of all the non-ETC1 formats.
- cTFBC7_M5, // Opaque+alpha, alpha channel will be opaque for opaque .basis files
- // PVRTC1 4bpp
- cTFPVRTC1_4_RGB, // Opaque only, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified, nearly lowest quality of any texture format.
- cTFPVRTC1_4_RGBA, // Opaque+alpha, most useful for simple opacity maps. If .basis file doens't have alpha cTFPVRTC1_4_RGB will be used instead. Lowest quality of any supported texture format.
- // ASTC
- cTFASTC_4x4, // Opaque+alpha, ASTC 4x4, alpha channel will be opaque for opaque .basis files. Transcoder uses RGB/RGBA/L/LA modes, void extent, and up to two ([0,47] and [0,255]) endpoint precisions.
- // ATC
- cTFATC_RGB, // Opaque, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified. ATI ATC (GL_ATC_RGB_AMD)
- cTFATC_RGBA_INTERPOLATED_ALPHA, // Opaque+alpha, alpha channel will be opaque for opaque .basis files. ATI ATC (ATC_RGBA_INTERPOLATED_ALPHA_AMD)
- cTFTotalBlockTextureFormats,
- // Uncompressed (raw pixel) formats
- cTFRGBA32 = cTFTotalBlockTextureFormats, // 32bpp RGBA image stored in raster (not block) order in memory, R is first byte, A is last byte.
- cTFRGB565, // 166pp RGB image stored in raster (not block) order in memory, R at bit position 11
- cTFBGR565, // 16bpp RGB image stored in raster (not block) order in memory, R at bit position 0
- cTFRGBA4444, // 16bpp RGBA image stored in raster (not block) order in memory, R at bit position 12, A at bit position 0
- cTFTotalTextureFormats
- };
- uint32_t basis_get_bytes_per_block(transcoder_texture_format fmt);
- const char* basis_get_format_name(transcoder_texture_format fmt);
- bool basis_transcoder_format_has_alpha(transcoder_texture_format fmt);
- basisu::texture_format basis_get_basisu_texture_format(transcoder_texture_format fmt);
- const char* basis_get_texture_type_name(basis_texture_type tex_type);
- bool basis_transcoder_format_is_uncompressed(transcoder_texture_format tex_type);
- bool basis_block_format_is_uncompressed(block_format tex_type);
- uint32_t basis_get_uncompressed_bytes_per_pixel(transcoder_texture_format fmt);
-
- class basisu_transcoder;
- // This struct holds all state used during transcoding. For video, it needs to persist between image transcodes (it holds the previous frame).
- // For threading you can use one state per thread.
- struct basisu_transcoder_state
- {
- struct block_preds
- {
- uint16_t m_endpoint_index;
- uint8_t m_pred_bits;
- };
- std::vector<block_preds> m_block_endpoint_preds[2];
-
- enum { cMaxPrevFrameLevels = 16 };
- std::vector<uint32_t> m_prev_frame_indices[2][cMaxPrevFrameLevels]; // [alpha_flag][level_index]
- };
-
- // Low-level helper class that does the actual transcoding.
- class basisu_lowlevel_transcoder
- {
- friend class basisu_transcoder;
-
- public:
- basisu_lowlevel_transcoder(const basist::etc1_global_selector_codebook *pGlobal_sel_codebook);
- bool decode_palettes(
- uint32_t num_endpoints, const uint8_t *pEndpoints_data, uint32_t endpoints_data_size,
- uint32_t num_selectors, const uint8_t *pSelectors_data, uint32_t selectors_data_size);
- bool decode_tables(const uint8_t *pTable_data, uint32_t table_data_size);
- bool transcode_slice(void *pDst_blocks, uint32_t num_blocks_x, uint32_t num_blocks_y, const uint8_t *pImage_data, uint32_t image_data_size, block_format fmt,
- uint32_t output_block_or_pixel_stride_in_bytes, bool wrap_addressing, bool bc1_allow_threecolor_blocks, const basis_file_header &header, const basis_slice_desc& slice_desc, uint32_t output_row_pitch_in_blocks_or_pixels = 0,
- basisu_transcoder_state *pState = nullptr, bool astc_transcode_alpha = false, void* pAlpha_blocks = nullptr, uint32_t output_rows_in_pixels = 0);
- private:
- typedef std::vector<endpoint> endpoint_vec;
- endpoint_vec m_endpoints;
- typedef std::vector<selector> selector_vec;
- selector_vec m_selectors;
- const etc1_global_selector_codebook *m_pGlobal_sel_codebook;
- huffman_decoding_table m_endpoint_pred_model, m_delta_endpoint_model, m_selector_model, m_selector_history_buf_rle_model;
- uint32_t m_selector_history_buf_size;
-
- basisu_transcoder_state m_def_state;
- };
- struct basisu_slice_info
- {
- uint32_t m_orig_width;
- uint32_t m_orig_height;
- uint32_t m_width;
- uint32_t m_height;
- uint32_t m_num_blocks_x;
- uint32_t m_num_blocks_y;
- uint32_t m_total_blocks;
- uint32_t m_compressed_size;
- uint32_t m_slice_index; // the slice index in the .basis file
- uint32_t m_image_index; // the source image index originally provided to the encoder
- uint32_t m_level_index; // the mipmap level within this image
-
- uint32_t m_unpacked_slice_crc16;
-
- bool m_alpha_flag; // true if the slice has alpha data
- bool m_iframe_flag; // true if the slice is an I-Frame
- };
- typedef std::vector<basisu_slice_info> basisu_slice_info_vec;
- struct basisu_image_info
- {
- uint32_t m_image_index;
- uint32_t m_total_levels;
- uint32_t m_orig_width;
- uint32_t m_orig_height;
- uint32_t m_width;
- uint32_t m_height;
- uint32_t m_num_blocks_x;
- uint32_t m_num_blocks_y;
- uint32_t m_total_blocks;
- uint32_t m_first_slice_index;
-
- bool m_alpha_flag; // true if the image has alpha data
- bool m_iframe_flag; // true if the image is an I-Frame
- };
- struct basisu_image_level_info
- {
- uint32_t m_image_index;
- uint32_t m_level_index;
- uint32_t m_orig_width;
- uint32_t m_orig_height;
- uint32_t m_width;
- uint32_t m_height;
- uint32_t m_num_blocks_x;
- uint32_t m_num_blocks_y;
- uint32_t m_total_blocks;
- uint32_t m_first_slice_index;
-
- bool m_alpha_flag; // true if the image has alpha data
- bool m_iframe_flag; // true if the image is an I-Frame
- };
- struct basisu_file_info
- {
- uint32_t m_version;
- uint32_t m_total_header_size;
- uint32_t m_total_selectors;
- uint32_t m_selector_codebook_size;
- uint32_t m_total_endpoints;
- uint32_t m_endpoint_codebook_size;
- uint32_t m_tables_size;
- uint32_t m_slices_size;
- basis_texture_type m_tex_type;
- uint32_t m_us_per_frame;
- // Low-level slice information (1 slice per image for color-only basis files, 2 for alpha basis files)
- basisu_slice_info_vec m_slice_info;
- uint32_t m_total_images; // total # of images
- std::vector<uint32_t> m_image_mipmap_levels; // the # of mipmap levels for each image
- uint32_t m_userdata0;
- uint32_t m_userdata1;
-
- bool m_etc1s; // always true for basis universal
- bool m_y_flipped; // true if the image was Y flipped
- bool m_has_alpha_slices; // true if the texture has alpha slices (even slices RGB, odd slices alpha)
- };
- // High-level transcoder class which accepts .basis file data and allows the caller to query information about the file and transcode image levels to various texture formats.
- // If you're just starting out this is the class you care about.
- class basisu_transcoder
- {
- basisu_transcoder(basisu_transcoder&);
- basisu_transcoder& operator= (const basisu_transcoder&);
- public:
- basisu_transcoder(const etc1_global_selector_codebook *pGlobal_sel_codebook);
- // Validates the .basis file. This computes a crc16 over the entire file, so it's slow.
- bool validate_file_checksums(const void *pData, uint32_t data_size, bool full_validation) const;
- // Quick header validation - no crc16 checks.
- bool validate_header(const void *pData, uint32_t data_size) const;
- basis_texture_type get_texture_type(const void *pData, uint32_t data_size) const;
- bool get_userdata(const void *pData, uint32_t data_size, uint32_t &userdata0, uint32_t &userdata1) const;
-
- // Returns the total number of images in the basis file (always 1 or more).
- // Note that the number of mipmap levels for each image may differ, and that images may have different resolutions.
- uint32_t get_total_images(const void *pData, uint32_t data_size) const;
- // Returns the number of mipmap levels in an image.
- uint32_t get_total_image_levels(const void *pData, uint32_t data_size, uint32_t image_index) const;
-
- // Returns basic information about an image. Note that orig_width/orig_height may not be a multiple of 4.
- bool get_image_level_desc(const void *pData, uint32_t data_size, uint32_t image_index, uint32_t level_index, uint32_t &orig_width, uint32_t &orig_height, uint32_t &total_blocks) const;
- // Returns information about the specified image.
- bool get_image_info(const void *pData, uint32_t data_size, basisu_image_info &image_info, uint32_t image_index) const;
- // Returns information about the specified image's mipmap level.
- bool get_image_level_info(const void *pData, uint32_t data_size, basisu_image_level_info &level_info, uint32_t image_index, uint32_t level_index) const;
-
- // Get a description of the basis file and low-level information about each slice.
- bool get_file_info(const void *pData, uint32_t data_size, basisu_file_info &file_info) const;
-
- // start_transcoding() must be called before calling transcode_slice() or transcode_image_level().
- // This decompresses the selector/endpoint codebooks, so ideally you would only call this once per .basis file (not each image/mipmap level).
- bool start_transcoding(const void *pData, uint32_t data_size) const;
-
- // Returns true if start_transcoding() has been called.
- bool get_ready_to_transcode() const { return m_lowlevel_decoder.m_endpoints.size() > 0; }
- enum
- {
- // PVRTC1: texture will use wrap addressing vs. clamp (most PVRTC viewer tools assume wrap addressing, so we default to wrap although that can cause edge artifacts)
- cDecodeFlagsPVRTCWrapAddressing = 1,
-
- // PVRTC1: decode non-pow2 ETC1S texture level to the next larger power of 2 (not implemented yet, but we're going to support it). Ignored if the slice's dimensions are already a power of 2.
- cDecodeFlagsPVRTCDecodeToNextPow2 = 2,
-
- // When decoding to an opaque texture format, if the basis file has alpha, decode the alpha slice instead of the color slice to the output texture format.
- // This is primarily to allow decoding of textures with alpha to multiple ETC1 textures (one for color, another for alpha).
- cDecodeFlagsTranscodeAlphaDataToOpaqueFormats = 4,
- // Forbid usage of BC1 3 color blocks (we don't support BC1 punchthrough alpha yet).
- // This flag is used internally when decoding to BC3.
- cDecodeFlagsBC1ForbidThreeColorBlocks = 8,
- // The output buffer contains alpha endpoint/selector indices.
- // Used internally when decoding formats like ASTC that require both color and alpha data to be available when transcoding to the output format.
- cDecodeFlagsOutputHasAlphaIndices = 16,
- };
-
- // transcode_image_level() decodes a single mipmap level from the .basis file to any of the supported output texture formats.
- // It'll first find the slice(s) to transcode, then call transcode_slice() one or two times to decode both the color and alpha texture data (or RG texture data from two slices for BC5).
- // If the .basis file doesn't have alpha slices, the output alpha blocks will be set to fully opaque (all 255's).
- // Currently, to decode to PVRTC1 the basis texture's dimensions in pixels must be a power of 2, due to PVRTC1 format requirements.
- // output_blocks_buf_size_in_blocks_or_pixels should be at least the image level's total_blocks (num_blocks_x * num_blocks_y), or the total number of output pixels if fmt==cTFRGBA32.
- // output_row_pitch_in_blocks_or_pixels: Number of blocks or pixels per row. If 0, the transcoder uses the slice's num_blocks_x or orig_width (NOT num_blocks_x * 4). Ignored for PVRTC1 (due to texture swizzling).
- // output_rows_in_pixels: Ignored unless fmt is cRGBA32. The total number of output rows in the output buffer. If 0, the transcoder assumes the slice's orig_height (NOT num_blocks_y * 4).
- // Notes:
- // - basisu_transcoder_init() must have been called first to initialize the transcoder lookup tables before calling this function.
- // - This method assumes the output texture buffer is readable. In some cases to handle alpha, the transcoder will write temporary data to the output texture in
- // a first pass, which will be read in a second pass.
- bool transcode_image_level(
- const void *pData, uint32_t data_size,
- uint32_t image_index, uint32_t level_index,
- void *pOutput_blocks, uint32_t output_blocks_buf_size_in_blocks_or_pixels,
- transcoder_texture_format fmt,
- uint32_t decode_flags = cDecodeFlagsPVRTCWrapAddressing, uint32_t output_row_pitch_in_blocks_or_pixels = 0, basisu_transcoder_state *pState = nullptr, uint32_t output_rows_in_pixels = 0) const;
- // Finds the basis slice corresponding to the specified image/level/alpha params, or -1 if the slice can't be found.
- int find_slice(const void *pData, uint32_t data_size, uint32_t image_index, uint32_t level_index, bool alpha_data) const;
- // transcode_slice() decodes a single slice from the .basis file. It's a low-level API - most likely you want to use transcode_image_level().
- // This is a low-level API, and will be needed to be called multiple times to decode some texture formats (like BC3, BC5, or ETC2).
- // output_blocks_buf_size_in_blocks_or_pixels is just used for verification to make sure the output buffer is large enough.
- // output_blocks_buf_size_in_blocks_or_pixels should be at least the image level's total_blocks (num_blocks_x * num_blocks_y), or the total number of output pixels if fmt==cTFRGBA32.
- // output_block_stride_in_bytes: Number of bytes between each output block.
- // output_row_pitch_in_blocks_or_pixels: Number of blocks or pixels per row. If 0, the transcoder uses the slice's num_blocks_x or orig_width (NOT num_blocks_x * 4). Ignored for PVRTC1 (due to texture swizzling).
- // output_rows_in_pixels: Ignored unless fmt is cRGBA32. The total number of output rows in the output buffer. If 0, the transcoder assumes the slice's orig_height (NOT num_blocks_y * 4).
- // Notes:
- // - basisu_transcoder_init() must have been called first to initialize the transcoder lookup tables before calling this function.
- bool transcode_slice(const void *pData, uint32_t data_size, uint32_t slice_index,
- void *pOutput_blocks, uint32_t output_blocks_buf_size_in_blocks_or_pixels,
- block_format fmt, uint32_t output_block_stride_in_bytes, uint32_t decode_flags = cDecodeFlagsPVRTCWrapAddressing, uint32_t output_row_pitch_in_blocks_or_pixels = 0, basisu_transcoder_state * pState = nullptr, void* pAlpha_blocks = nullptr, uint32_t output_rows_in_pixels = 0) const;
- private:
- mutable basisu_lowlevel_transcoder m_lowlevel_decoder;
- int find_first_slice_index(const void* pData, uint32_t data_size, uint32_t image_index, uint32_t level_index) const;
-
- bool validate_header_quick(const void* pData, uint32_t data_size) const;
- };
- // basisu_transcoder_init() must be called before a .basis file can be transcoded.
- void basisu_transcoder_init();
- enum debug_flags_t
- {
- cDebugFlagVisCRs = 1,
- cDebugFlagVisBC1Sels = 2,
- cDebugFlagVisBC1Endpoints = 4
- };
- uint32_t get_debug_flags();
- void set_debug_flags(uint32_t f);
- } // namespace basisu
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