Python support is still new and coming online, but is entirely functional. The library‘s pure C (WASM friendly) API’s are completely exposed to Python. Our next goal is to work on official Wheels, once the API is settled and more examples are written.

The Python integration first tries to use native .so‘s in the basisu_py directory. If they don’t exist, it tries the slower and single threaded WASM fallbacks under basisu_py/wasm, which requires wasmtime for Python to be installed. Some tests require an input.ktx2 or test.ktx2 to be in the current directory.

Building:

Under the repo‘s root directory - build the native SO’s:

mkdir build_python
cd build_python
cmake -DBASISU_BUILD_PYTHON=ON ..
make

Build the WASM modules (see README_WASI.md file for instructions on how to install the WASI SDK, which is required):

mkdir build_wasm_st
cd build_wasm_st
cmake .. -DCMAKE_TOOLCHAIN_FILE=$WASI_SDK_PATH/share/cmake/wasi-sdk.cmake -DCMAKE_BUILD_TYPE=Release -DBASISU_WASM_THREADING=OFF
make

Running Tests

The tests assume the current directory is “python”. Under Windows we've tested with Python v3.12.10, and under Linux v3.12.13.

Higher-level tests:

• python3 -m tests.test_backend_loading
• python3 -m tests.test_basic_wasm_selection
• python3 -m tests.test_basic_backend_selection
• python3 -m tests.test_basic_decode
• python3 -m tests.test_basic_transcode
• python3 -m tests.test_compress_swirl
• python3 -m tests.test_compress_swirl_hdr
• python3 -m tests.test_transcoder_astc
• python3 -m tests.test_transcoder_backend_loading
• python3 -m tests.test_transcoder_end_to_end
• python3 -m tests.test_transcoder_end_to_end_hdr
• python3 -m tests.test_transcoder_helpers

Low-level tests (used while bringing up the codec):

• python3 -m lowlevel_test_native.basic_test
• python3 -m lowlevel_test_native.test_transcoder_basic
• python3 -m lowlevel_test_native.example_capi_python
• python3 -m lowlevel_test_wasm.basic_test
• python3 -m lowlevel_test_wasm.compress_test
• python3 -m lowlevel_test_wasm.compress_test_float

Example output:

richg@ryzen9:/mnt/c/dev/bu_1_22_snapshot2/basis_universal-master/python$ python3 -m tests.test_backend_loading
========== BACKEND LOADING TEST ==========

Testing native backend...
[Encoder] Using native backend
  [OK] Native backend loaded
Hello from basisu_wasm_api.cpp version 200
  Native get_version() ? 200
  Native alloc() returned ptr = 685784256
  Native free() OK
  [OK] Native basic operations working.


Testing WASM backend...
[WASM Encoder] Loaded: /mnt/c/dev/bu_1_22_snapshot2/basis_universal-master/python/basisu_py/wasm/basisu_module_st.wasm
[Encoder] Using WASM backend
  [OK] WASM backend loaded
Hello from basisu_wasm_api.cpp version 200
  WASM get_version() ? 200
  WASM alloc() returned ptr = 26920160
  WASM free() OK
  [OK] WASM basic operations working.


========== DONE ==========