10-bit (default): Rgb10a2Unorm, falling back to Rgba16Float then 8-bit; 8-bit: the previous hardcoded Bgra8Unorm/Rgba8Unorm. Selection is a pure function with unit tests; the env var is re-read on every surface (re)creation.
10-bit (default): Rgb10a2Unorm, falling back to Rgba16Float then 8-bit; 8-bit: the previous hardcoded Bgra8Unorm/Rgba8Unorm. Selection is a pure function with unit tests; the env var is re-read on every surface (re)creation.