CPU: https://raytracing.github.io/books/RayTracingInOneWeekend.html
OpenGL GPU: https://medium.com/@jcowles/gpu-ray-tracing-in-one-weekend-3e7d874b3b0f https://imgeself.github.io/posts/2019-06-26-raytracer-5-gpu-opengl/
Compute shaders https://github.com/jakubg05/Ray-Tracing https://kidrigger.dev/post/gpu-ray-tracing-in-one-weekend/ https://github.com/kidrigger/TracerGL https://github.com/LWJGL/lwjgl3-wiki/wiki/2.6.1.-Ray-tracing-with-OpenGL-Compute-Shaders-%28Part-I%29
Other: https://alain.xyz/blog/real-time-ray-tracing#articles