Since vulkan supports 32-bit indexes, there's no need for the
shenanigans the EGL-based glsl renderer had to go through to render bsp
models (maps often had quite a bit more than 65536 vertices), though the
reduced GPU memory requirements of 16-bit indices does have its
advantages.
Getting close to understanding (again) how it all works. I only just
barely understood when I got vulkan's renderer running, but I really
need to understand for when I modify things for shadows. The main thing
hurdle was tinst, but that was dealt with in the previous commit, and
now it's just sorting out the mess of elechains and elementss.
Loading is broken for multi-file image sets due to the way images are
loaded (this needs some thought for making it effecient), but the
Blender environment map loading works.
They're unlit (fullbright, but that's nothing new for quake), but
working nicely. As a bonus, sort out the sky pass (forced to due to the
way command buffers are used).
After getting lights even vaguely working for alias models, I realized
that it just wasn't going to be feasible to do nice lighting with
forward rendering. This gets the bulk of the work done for deferred
rendering, but still need to sort out the shaders before any real
testing can be done.
The sky texture is loaded with black's alpha set to 0. While this does
hit both layers, the screen is cleared to black so it shouldn't be a
problem (and will allow having a skybox behind the sheets).
Glow map and sky sheet and cube need to wait until I can get some
default textures going, but the world is rendering correctly otherwise
(though a tad dark: need to do a gamma setting).
