wow! you can step-debug GLSL pixel shaders in #renderdoc. Was interested why one particular pixel becomes black, clicked Debug button and... it just worked. Apparently there are limitations, but it worked for me just fine.
#Renderdoc v1.42 released. #Vulkan #OpenGL
Release notes: https://github.com/baldurk/renderdoc/releases/tag/v1.42
Builds: https://renderdoc.org/builds