Flat bleeding shader

[jmickle66666666]

Flats will "bleed" into missing textures on upper/lower parts of a 2-sided linedef. GZDoom successfully replicates this behaviour in it's hardware renderer so there's no reason we can't do the same.

I imagine it will consist of passing the texture on the flat to the "missing texture shader" and calculate the texture coordinates based off a normal instead of the correct calculation?

[jmickle66666666]

Easy place to see this effect is just down the corridor on the left at the start of MAP14. The top edge of the window at the end has a missing texture. In software renderers and gzdoom's opengl renderer, the flat on the inside edge of the window bleeds onto the side.

I believe this is also use for the "Mordeth Bridge" effect seen in BTSX Map01