r1361 (and before) scrolling warping flat on wall jerkiness

[Enjay]

Try the attached file. On my computer, on the two vertically scrolling walls, the warping flat "jerks" every second or so. Horizontal scrolling seems to be OK as does putting the warping flat on a wall without scrolling it. It also seems to need to be warp2. Regular warp does not seem to cause the problem.

I checked the last official release and the problem goes back to at least there. It doesn't seem to affect ZDoom. Shader issue?

[Enjay]

Sorry for the bumpage but I just ran into this problem again and was about to post a bug report when I remembered this one. Obviously there hasn't been an opportunity to look at this because it still exists with the current code. I don't suppose it could be bumped up the priority list for checking as an when an opportunity arises? Thanks.

[Graf Zahl]

If I had any idea what's happening here I'd gladly fix it. Unfortunately it's a shader problem and those are not really debuggable.

[Enjay]

Ah, OK, thanks for explaining the difficulty.

[Graf Zahl]

fixed. This was a problem with the texture size not being a multiple of the sine period. I took the chance and changed the formula to exactly match the software renderer's.
The original shader was created with trial and error and was quite different, actually.