Because you forget to call glGetError and do the error check on your previous call. In a world where we are driven by exceptions, not excepting and requiring you to check is actually a good thing, you wouldn’t want a shader Parma exception from panicking your game in the middle of a gun fight.

glGetError() is useless unfortunately for getting any information about what went wrong, because it only has 8 error codes:

https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGetE...

There's a debug output extension (or core feature since 4.3) that's slightly more verbose, but not universally supported (e.g. AFAIK not on macOS).

What about Debug Output? https://www.khronos.org/opengl/wiki/Debug_Output

Using those debuggers is like doing CPU debugging.

If at least you had posted a link to RenderDoc.

It's better than glGetError() for sure, but not supported everywhere (e.g. macOS is stuck at 4.1 Core Profile).

That's a fantastic point. As much as I managed to do stuff in OpenGL for decades, it was definitely left behind DX and Metal in terms of API ergonomics.