OpenGL 1.x questions
1) glGetIntegerv, glGetFloatv, etc. These don't have to interact with the graphics card, right? So these are near "instant" and close to free? My guess is yes.
2) I do glEnable (GL_ALPHA_TEST). It was already on. Can I expect the driver to ignore this since it is redundant? My guess is yes or doesn't materially matter.
I worry about some of this stuff being left on accidentally (forgot to turn something off in code or restore it) and in the past, I've had to track down a couple of places where something "wasn't right" and then find where something wasn't restored.
If I check the state of every GL capability I care about (probably 20 of them at most) before drawing an entity, is that going to affect performance? My guess is no because even if it did, say, 6000 glGetFloatv/glGetIntegerv per frame the speeds are similar to any other external library simple function call.
Now I probably plan to #ifdef _DEBUG this anyway so it is only in the debug build.