cTFETC1_RGB=0,// Opaque only, returns RGB or alpha data if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
cTFETC2_RGBA=1,// Opaque+alpha, ETC2_EAC_A8 block followed by a ETC1 block, alpha channel will be opaque for opaque .basis files
// BC1-5, BC7 (desktop, some mobile devices)
cTFBC1_RGB=2,// Opaque only, no punchthrough alpha support yet, transcodes alpha slice if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
cTFBC3_RGBA=3,// Opaque+alpha, BC4 followed by a BC1 block, alpha channel will be opaque for opaque .basis files
cTFBC4_R=4,// Red only, alpha slice is transcoded to output if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified
cTFBC5_RG=5,// 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_RGB=6,// Opaque only, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified. Highest quality of all the non-ETC1 formats.
cTFBC7_M5_RGBA=7,// Opaque+alpha, alpha channel will be opaque for opaque .basis files
// PVRTC1 4bpp (mobile, PowerVR devices)
cTFPVRTC1_4_RGB=8,// Opaque only, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified, nearly lowest quality of any texture format.
cTFPVRTC1_4_RGBA=9,// 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 (mobile, Intel devices, hopefully all desktop GPU's one day)
cTFASTC_4x4_RGBA=10,// 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 (mobile, Adreno devices, this is a niche format)
cTFATC_RGB=11,// Opaque, RGB or alpha if cDecodeFlagsTranscodeAlphaDataToOpaqueFormats flag is specified. ATI ATC (GL_ATC_RGB_AMD)
cTFATC_RGBA=12,// Opaque+alpha, alpha channel will be opaque for opaque .basis files. ATI ATC (GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD)
// FXT1 (desktop, Intel devices, this is a super obscure format)
cTFFXT1_RGB=17,// Opaque only, uses exclusively CC_MIXED blocks. Notable for having a 8x4 block size. GL_3DFX_texture_compression_FXT1 is supported on Intel integrated GPU's (such as HD 630).
// Punch-through alpha is relatively easy to support, but full alpha is harder. This format is only here for completeness so opaque-only is fine for now.
// See the BASISU_USE_ORIGINAL_3DFX_FXT1_ENCODING macro in basisu_transcoder_internal.h.
cTFPVRTC2_4_RGB=18,// Opaque-only, almost BC1 quality, much faster to transcode and supports arbitrary texture dimensions (unlike PVRTC1 RGB).
cTFPVRTC2_4_RGBA=19,// Opaque+alpha, slower to encode than cTFPVRTC2_4_RGB. Premultiplied alpha is highly recommended, otherwise the color channel can leak into the alpha channel on transparent blocks.
cTFETC2_EAC_R11=20,// R only (ETC2 EAC R11 unsigned)
cTFETC2_EAC_RG11=21,// RG only (ETC2 EAC RG11 unsigned), R=opaque.r, G=alpha - for tangent space normal maps
boolm_alpha_flag;// true if the image has alpha data
boolm_iframe_flag;// true if the image is an I-Frame
};
structbasisu_image_level_info
{
uint32_tm_image_index;
uint32_tm_level_index;
uint32_tm_orig_width;
uint32_tm_orig_height;
uint32_tm_width;
uint32_tm_height;
uint32_tm_num_blocks_x;
uint32_tm_num_blocks_y;
uint32_tm_total_blocks;
uint32_tm_first_slice_index;
boolm_alpha_flag;// true if the image has alpha data
boolm_iframe_flag;// true if the image is an I-Frame
};
structbasisu_file_info
{
uint32_tm_version;
uint32_tm_total_header_size;
uint32_tm_total_selectors;
uint32_tm_selector_codebook_size;
uint32_tm_total_endpoints;
uint32_tm_endpoint_codebook_size;
uint32_tm_tables_size;
uint32_tm_slices_size;
basis_texture_typem_tex_type;
uint32_tm_us_per_frame;
// Low-level slice information (1 slice per image for color-only basis files, 2 for alpha basis files)
basisu_slice_info_vecm_slice_info;
uint32_tm_total_images;// total # of images
std::vector<uint32_t>m_image_mipmap_levels;// the # of mipmap levels for each image
uint32_tm_userdata0;
uint32_tm_userdata1;
boolm_etc1s;// always true for basis universal
boolm_y_flipped;// true if the image was Y flipped
boolm_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.
// 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.
// 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.
// 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.
