OpenGL sometimes will not skew midtextures consistently

This might be related to #527 (moved), so I figured I'd submit it here.

As you can see, the left midtexture does not skew properly on one side. I've tried flipping the lines, making new sectors, but nothing seems to fix this. I've encountered this issue in SRB2 as well as SRB2Kart, meaning this isn't just a v2.2 bug. Neither lines have the "No Midtexture Skew" flag set. They're both just lines with pegged GFZGRASS using the "Peg Midtexture" flag. The behavior works completely fine in Software mode, however..

This only happens in OpenGL, and seems related to when one end of the side of a slope is exactly 0 units above/below the surrounding floor.

It also seems to render in ZB's Visual Mode, but that might've been fixed in a later version since I'm using v2.9 right now.

changed title from Sloped midtextures will sometimes not skew for no apparent reason to OpenGL sometimes will not skew midtextures consistently

changed the description

Duplicate or related: #195 (closed)

added Bug OpenGL renderer labels

closed