This only applies to the background for now:
- support for alpha for vertex colors in custom levels
- switch time of day palette generation from octree to k-d tree
- support for alpha masking in custom levels
- support for transparent textures
- support for envmap in custom levels
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Co-authored-by: water111 <awaterford1111445@gmail.com>
This adds hfrag, but with a few remaining issues:
- The textures aren't animated. Instead, it just uses one texture.
- The texture filtering isn't as good as at it could be.
I also cleaned up a few issues with the background renderers:
- Cleaned up some stuff that is common to hfrag, tie, tfrag, shrub
- Moved time-of-day color packing stuff to FR3 creation, rather than at
level load. This appears to reduce the frame time spikes when a level is
first drawn by about 5 or 6 ms in big levels.
- Cleaned up the x86 specific stuff used in time of day. Now there's
only one place where we have an `ifdef`, rather than spreading it all
over the rendering code.
water111