Rust binding and wrappers for the Basis Universal pure C API.

Rust binding and wrappers for the basisu pure C API, through FFI on native and wasm32. See also https://github.com/BinomialLLC/basis_universal/wiki#encoder-and-transcoding-c-api-documentation.

This crate also contains an optional high level API that is easier to use with wgpu-types. Enabling the extra cargo feature to use the high level BasisuEncoder and BasisuTranscoder.

Implementation details on wasm build

Greatly inspired by https://github.com/rafaelbeckel/test-c-rust-wasm

The wasm build compiles the Basis Universal C++ sources together with a vendored musl libc and emscripten libc++/libc++abi directly from source.

⚠️ Note: this requires a relatively new clang version (Ubuntu 26.04 with clang 21 is tested in CI).

Feature flags

• encoder: Enable basisu encoder, which will significantly increase the binary size. By default only transcoder is enabled.
• serde: Enable serde on some structs.
• extra: Enable extra high level encoder and transcoder API that is easier to use with wgpu-types.
• std

Feature flags to enable specific transcode target:

• transcode_etc1s_bc1

• transcode_etc1s_bc3

• transcode_default:

  • transcode_etc1s_bc4_5
  • transcode_etc1s_bc7
  • transcode_etc1s_etc2
  • transcode_uastc
  • transcode_uastc_hdr
  • transcode_xuastc
  • transcode_astc

It's recommended to disable unused targets (especially for ETC1S) to reduce binary size.

PVRTC1, ATC, FXT1, PVRTC2 are always disabled since they are rarely used. Note: Some combinations may fail to compile due to upstream bugs.