Fixed Switching renders can mess up sector flat alignments

[DirkTheHusky]

When switching between Software and OpenGL, the sectors that uses the sector flat alignment effects mess up. Example of this issue are some of the roads on ACZ1, where the 2 yellow lines aren't connecting.

 

[toaster]

The OpenGL flat alignment on slopes is actually more accurate as a whole, the software renderer was just too imprecise to do it well and the level was designed in a way as to try and hide the imperfection in the renderer more people would play in.