This reuses the FTexCoordInfo class the hardware renderer had been using to calculate wall texture offsetting.
The software renderers still need this sorted out to bring them in line with the rest of the code, though, but they do not have this code sufficiently well organized to make this a straightforward task.
This was a relic from trying to support ZDoomGL's texture shader system but would make texture management with Vulkan significantly more complicated because it would require dynamic descriptor set management for textures which can cause a lot of overhead.
