Graphical error?

[JTE]

In order to create an open-sky area like Aerial Garden, the trick is that the thok barrier needs to have a floor other than F_SKY. As long as the thok barrier has a floor texture, it will still work right. That's why AGZ has that ring of ruins that you can't land on or do anything to around the entire stage. It's the thok barrier. It's a rather annoying quirk, but at least there is a workaround.

I tried that. For some reason, Rock Skull Mountain Zone needs the floor and ceiling to be seperated. And most other Thok barriers won't even accept that, for some reason. Maybe I have an outdated ZenNode? It's like SRB2-Playah's problem: You can't see the sky on both the floor and the ceiling at the same time. I have a feeling that the only reason it works in Rock Skull Mountain is because the ceiling is so high above the floor anyway or something.

 

[a441]

I was using ZenNode 1.0.8 until recently. It has occasional problems with OpenGL, but otherwise works fine. The only particular sky bug I know of, other than what Mystic described, is if you have a sector with both the floor and ceiling set to sky and it also has FOFs, it can't be touching the thok barrier.

The sky also glitches in extremely large areas, where it seems to have no other specific cause. (Example: Nimbus Ruins Zone.)

 

[Mystic]

The sky glitch in large areas only occurs in software. You can see it a lot in Nimbus Ruins and any very large open-air stage.

Another interesting sky glitch for those who are interested is that if you place a FOF next to a thok barrier, you will see sky instead of the floor of the thok barrier when looking from the FOF to the thok barrier. A really easy place to see that is Chaos Space's water on the outside where it touches the thok barrier.

Most renderer bugs fortunately are rather harmless, since many of them are pretty much unfixable.

 

[a441]

All the sky glitches mentioned here are exclusive to software.

 

[SRB2-Playah]

I think that the walls-in-the-sky thing has something to do with... What was it called? Mip-mapping? Something like that... Not Bitmap.
the thing where a program makes several diffrent-sized copies of a texture, and display them depending on how far away you are.
I think it has something to do with that, Since it happens when you're in a really large empty area. The texure is soooo far away, the Mip-mapping messes up.
But, that's just a guess.

 

[a441]

Mipmapping is a feature of video cards, only used in hardware render mode (OpenGL). The glitches we're talking about are present only in software render.

 

[SRB2-Playah]

Oh.
Nevermind, then.

 

[SSNTails]

It probably has to do with overflow on the fixed_t variable types.

 

[a441]

The "large area" glitches, sure, but you can just make a tiny thok-barriered open-air map, and give a sector neighboring the thok barrier a floor and ceiling of F_SKY1, and add an FOF, and you get a sky glitch. Even if there's nothing that could overflow a short there.