adjustable separate render resolution

[NuclearMonster]

this might seem silly but the reason is because with an adjustable render resolution (separate from display resolution? not sure of the terminology here) we could have a more "traditional" quake look without also doing shaders, and in a scenario where someone has a modern game made with ioquake3 you could lower the render resolution without changing the display resolution. Potentially handy for like mobile GPUs and other lower power scenarios.

[Calinou]

This is also good to perform SSAA for modern GPUs, which often have plenty of headroom to improve visuals beyond MSAA.

Quake 3 isn't too impacted by specular aliasing, but alpha-tested geometry still has aliasing if you use MSAA alone (as ioquake3 lacks alpha-to-coverage support, which is an OpenGL 3.x feature).