3 unstable releases

0.1.1 Jun 25, 2024
0.1.0 Jun 19, 2024
0.0.5 Jul 25, 2023

#75 in Images

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95 downloads per month
Used in 3 crates

MIT/Apache

345KB
7.5K SLoC

texture2ddecoder Build Status Latest Version Docs License_MIT License_APACHE

A pure Rust no-std texture decoder for the following formats:

and with alloc:

Features

alloc (optional, default)

  • ~35% faster pvrtc decoding
  • crunch decoding

Functions

Provides a decode function for each format, as well as a block decode function all formats besides PVRTC. Besides some exceptions, the signature of the decode functions is as follows:

    fn decode_format(data: &[u8], width: usize, height: usize, image: &mut [u32]) -> Result<(), &'static str>
    // data: the compressed data, expected to be width * height / block_size in size
    // width: the width of the image
    // height: the height of the image
    // image: the buffer to write the decoded image to, expected to be width * height in size
    fn decode_format_block(data: &[u8], outbuf: &mut [u32]) -> Result<(), &'static str>
    // data: the compressed data (block), expected to be block_size in size
    // outbuf: the buffer to write the decoded image to, expected to be block_size in size

The exceptions are:

  • ASTC: the (block) decode function takes the block size as an additional parameter
  • BC6: there are two additional decode functions for the signed and unsigned variants
  • PVRTC: the decode function takes the block size as an additional parameter, and there are two additional decode functions for the 2bpp and 4bpp variants
  • Crunch & Unity's Crunch: The texture's dimensions and metadata are stored in the file itself, the header must be parsed with crnd_get_texture_info() from CrnTextureInfo struct first, then pass the metadata to the decoder. There's no block decompression function.

Here is a list of the formats and their corresponding functions:

  • ATC
    • decode_atc_rgb4
    • decode_atc_rgb4_block
    • decode_atc_rgba8
    • decode_atc_rgba8_block
  • ASTC
    • decode_astc
    • decode_astc_block
    • various decode_astc_(block_)_x_y functions, where x and y are the block size
  • BCn
    • decode_bc1
    • decode_bc1_block
    • decode_bc3
    • decode_bc3_block
    • decode_bc4
    • decode_bc4_block
    • decode_bc5
    • decode_bc5_block
    • decode_bc6
    • decode_bc6_block
    • decode_bc6_signed
    • decode_bc6_block_signed
    • decode_bc6_unsigned
    • decode_bc6_block_unsigned
    • decode_bc7
    • decode_bc7_block
  • ETC
    • decode_etc1
    • decode_etc1_block
    • decode_etc2_rgb
    • decode_etc2_rgb_block
    • decode_etc2_rgba1
    • decode_etc2_rgba1_block
    • decode_etc2_rgba8
    • decode_etc2_rgba8_block
    • decode_eacr
    • decode_eacr_block
    • decode_eacr_signed
    • decode_eacr_signed_block
    • decode_eacrg
    • decode_eacrg_block
  • PVRTC
    • decode_pvrtc
    • decode_pvrtc_2bpp
    • decode_pvrtc_4bpp
  • Crunch
    • decode_crunch
  • Unity Crunch
    • decode_unity_crunch

Roadmap

  • documentation
  • replacing u32 color output with RGBA structure
  • finding the original sources for the decoders
  • supporting more than BGRA32 output
  • adding additional formats

Format Progress

  • ATC-RGB
  • ATC-RGBA
  • ASTC
  • BC1
  • BC3
  • BC4
  • BC5
  • BC6
  • BC7
  • EAC-R
  • EAC-RG
  • ETC1
  • ETC2
  • ETC2-A1
  • ETC2-A8
  • PVRTCI-2bpp
  • PVRTCI-4bpp
  • Crunched
    • DXT1
    • DXT5
    • ETC1
    • ETC2-A8

License & Credits

This crate itself is dual-licensed under MIT + Apache2.

The texture compression codecs themselves have following licenses:

Codec License Source
ATC MIT Perfare/AssetStudio - Texture2DDecoderNative/atc.cpp
ASTC MIT* Ishotihadus/mikunyan - ext/decoders/native/astc.c
BCn MIT* Perfare/AssetStudio - Texture2DDecoderNative/bcn.cpp
ETC MIT* Ishotihadus/mikunyan - ext/decoders/native/etc.c
f16 MIT Maratyszcza/FP16
PVRTC MIT* Ishotihadus/mikunyan - ext/decoders/native/pvrtc.c
Crunch PUBLIC DOMAIN BinomialLLC/crunch
Crunch (Unity) ZLIB Unity-Technologies/crunch
* in doubt if these are the original source and have not just taken/adopted the code from somewhere else

Dependencies