Demo source code is not often released, but there are many exceptions. For example, if you're interested in 4kB intros, look at this: https://github.com/in4k
Since 4kB intros are typically done in a shader, you can also look at https://www.shadertoy.com
For Ctrl-Alt-Test specifically, we put our source code on GitHub (but not the most recent productions)[1]. The tool to minify shaders is also on GitHub[2].
So I think you can get a pretty good idea of how we did it. If you have any question, feel free to ask. I can give more details here, or it can be part of a future blog post.
Thanks for sharing! Your F – Felix’s Workshop[1] is pretty impressive, and specially for the 64KB category. Thanks for publishing the source code[2] as well.
For Ctrl-Alt-Test specifically, we put our source code on GitHub (but not the most recent productions)[1]. The tool to minify shaders is also on GitHub[2].
So I think you can get a pretty good idea of how we did it. If you have any question, feel free to ask. I can give more details here, or it can be part of a future blog post.
[1] https://github.com/laurentlb/Ctrl-Alt-Test [2] https://github.com/laurentlb/Shader_Minifier