Rendering glitch with strong pitch

[Gez]

When looking up or down, but not straight vertically, sometimes part of the visible world geometry ceases to be rendered in the corner. Perhaps excessive culling of subsectors? Most times, it merely causes a flickering effect when turning, but more rarely you can get the missing part to remain missing on a static scene. It seems more likely to happen in detailed maps. I've managed to get some screenshots of the effect in Valiant and Sunlust. Pay attention to the lower corners.

For example:

Those little slivers of sky on both sides? That's on Sunlust MAP31, ca. 3835, , -1147, too bad idmypos doesn't show angle and pitch as well.


Sunlust MAP23, ca. 3180, -1010


This one is Valiant MAP24 IIRC. Forgot the precise coordinates but there were plenty of areas with the problem around the cathedral.

I have seen it in other wads as well but due to its flickering nature it's pretty hard to screenshot. I have also seen it happen when looking up, though that situation comes up less often in play so don't have a screenshot of it.

[Graf Zahl]

This seems to have been emphasized when aspect ratio correction was moved from the projection to the view matrix. The effect has been there forever but it was quite rare.

[NeuralStunner]

The effect has been there forever but it was quite rare.

I've seen it a few times in detailed areas with a lot of midtextures. I don't remember the last time I saw it, I might have assumed it was a temporary issue.