It turned out the bindless approach wouldn't work too well for my design
of the sprite objects, but I don't think that's a big issue at this
stage (and it seems bindless is causing problems for brush/alias
rendering via renderdoc and on my versa pro). However, I have figured
out how to make effective use of descriptor sets (finally :P).
The actual normal still needs checking, but the sprites are currently
unlit so not an issue at this stage.
This adds the shaders and the pipeline specs. I'm not sure that the
deferred rendering side of the render pass is appropriate, but I thought
I'd give it a go, since quake sprites are really cutoff rather than
translucent.