[0.4.0][Duke3D: NW] Texture Flickering bug

[Cacodemon345]

In the Forgotten Land of Toys map, there is a texture flickering issue at this section of this map. Moving the player will cause it to flicker.

[Graf Zahl]

Can you make a savegame of that spot so that I don't have to find it myself? I never played that mod so I have no idea where to look.

[Cacodemon345]

Here it is.
https://drive.google.com/file/d/15DHxpf ... sp=sharing
(Hopefully I uploaded the correct file)

[Graf Zahl]

This is a weird one. There's two places in this map being affected by it. I could observe a similar bug on occasion in the first map of Blood on occasion, but far less reliably. It also tends to manifest itself as HOM instead of black triangles. The whole thing is also resolution dependent. A place where it glitches will render fine if the screen size is minimally changed and glitch where it previously did not.
The entire thing looks like a math error in Polymost somewhere - probably a fixed point overflow - but the entire math in there is fixed point voodoo that's incredibly hard to read.

What puzzles me is that in EDuke - a somewhat older build from the beginning of December - I cannot see it.

[Redneckerz]

This is a weird one. There's two places in this map being affected by it. I could observe a similar bug on occasion in the first map of Blood on occasion, but far less reliably. It also tends to manifest itself as HOM instead of black triangles. The whole thing is also resolution dependent. A place where it glitches will render fine if the screen size is minimally changed and glitch where it previously did not.
The entire thing looks like a math error in Polymost somewhere - probably a fixed point overflow - but the entire math in there is fixed point voodoo that's incredibly hard to read.

What puzzles me is that in EDuke - a somewhat older build from the beginning of December - I cannot see it.

Do note - but you are already aware of this as i saw a comment from you by it - that Terminx did a huge commit recently. It may very well be related to this (Just hunching.)

[Graf Zahl]

That "huge commit" was related to input handling, not rendering. This one looks like a math error in Polymost.

[Redneckerz]

Noted, thanks.

[Graf Zahl]

Looks like I found it, there was some leftover code that no longer exists in the upstream repos and removing this code seems to have cured the glitches.

[sinisterseed]

Groovy.

Now if only we could get rid of the sprites/voxel flickering in games...

[Graf Zahl]

That's going to be harder. This was merely some missed commit, the sprite flickering looks like an algorithmic problem, i.e. a lot harder to find and fix.

[sinisterseed]

I was actually thinking of the same thing.

The curios aspect is that I don't recall seeing this in neither NBlood or EDuke32, maybe it's another case of old code not playing well with the new backend.