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.
The vertices and frame images are loaded into the one memory object,
with the vertices first followed by the images.
The vertices are 2D xy+uv sets meant to be applied to the model
transform frame, and are pre-computed for the sprite size (this part
does support sprites with varying frame image sizes).
The frame images are loaded into one image with each frame on its own
layer. This will cause some problems if any sprites with varying frame
image sizes are found, but the three sprites in quake are all uniform
size.
