An example using mixbox [0], with a side-by-side comparison against mix().
Mostly written on-site during mountainbytes 2025.

code, graphics by noneofyourbusiness
music (donated) from Doctor Gekil doctorgekil@yahoo.fr - Gloom, using 64klang

This demo has been built for x86_64-linux-musl, it can be built for other systems.
It runs on alpine linux, if you install the dependencies.
The dependencies are: opusfile, sdl, vulkan.

Tools used: vis (text editor)[1], vulkan shadertoy (a tool that I wrote)[2], tiny C compiler[3], glslc[4]
The sources for the shader are available at yet another git repository [5].
Audio was converted from mp3 to opus with ffmpeg.

[0] https://github.com/scrtwpns/mixbox
[1] https://github.com/martanne/vis/
[2] https://git.sr.ht/~noneofyourbusiness/vulkan_shadertoy @ 01ef4b6cc2687d73d1899fd1835491e2e5e74c40
[3] https://repo.or.cz/tinycc.git
[4] https://github.com/google/shaderc
[5] https://git.sr.ht/~noneofyourbusiness/vulkan_shadertoy_shaders @ c50d28723d82f1fa527f167700d2a8edfeaf1800