Before Vulkan, if you wanted to do graphics debugging like step-through on pixel shaders, your options were Direct3D + PIX or, if you had access to them, game c

Before Vulkan, if you wanted to do graphics debugging like step-through on pixel shaders, your options were Direct3D + PIX or, if you had access to them, game console dev tools. Maybe Apple had something? Obviously, lots of games only had an OpenGL backend. So those devs simply didn't have access to those tools. It's the one outlier API with bad tooling.