[OGL] FlatSky rendering support

[Zeberpal]

I've made a supporting wad[zdoom-only] to this suggestion of why it could be a good idea. It's just a very small variation of how flatskies could be usefull.

Flatskies along with Gzdoom-only feautures could provide some interesting graphic results, and may cause in making nonstandard beautiful ideas on doom engine.

At this moment Gzdoom is not able to "flat" skies. It stretch them. Stretched skies are extremely unreliable when it comes to graphic accuracy.

Just using many skies, no matter if it is a "sky texture" or "skybox" method were used, it cause glitch results in gzdoom, which won't happen in software mode(flat).

How to use:
To save compatibility, it could be defined which sky(texture) will be flatrendered in GLDEFS.

[InsanityBringer]

Define "flat sky"

If you mean skies rendered the same way as software, it's technically possible, but you run into trouble with the fact you can look all the way up and down

[ZZYZX]

It can just go into gradient and solid color at some point (over/under software caps), for example.

Also while I think this could be replicated with shaders in GZDoom instead of using gross hacks, the feature itself would be nice to have to complete the software emulation along with software lightmode.

[Graf Zahl]

It can just go into gradient and solid color at some point (over/under software caps), for example.

No, it can't. At high angles the projection would completely fall apart and look weird. The software way of projecting a sky does not work well with real view pitching, it works to a reasonable degree with how the software renderer does it.

[ZZYZX]

No, it can't. At high angles the projection would completely fall apart and look weird. The software way of projecting a sky does not work well with real view pitching, it works to a reasonable degree with how the software renderer does it.

Looking at how this map does it, I believe that at least for it the sky should be projected like sprites, i.e. not exactly like software (always flat), but as a flat billboarded vertical polygon. Not sure how that would look like ingame.

edit: zzz it's a [No] already without any discussion. What's that even.

[Graf Zahl]

I consider this mostly pointless. It won't look good, only has use for edge cases. I have more important things to do.

[AdmiralAjax]

I consider this mostly pointless. It won't look good, only has use for edge cases. I have more important things to do.

Only for edge cases? You mean like, the edge case of every map in Doom ever???? But yeah, I'm sure rewriting [NO]Doom five more times is so important.

You do know that when emulator developers say that the emulators they make are only for archival purposes, they're only saying that to save their asses, right?

[Caligari87]

G/ZDoom isn't an emulator. It's an advanced source port focusing on advanced features, and in some cases those advanced features (like LOOKING UP AND DOWN) trump accuracy. If you want accuracy, play on Chocolate Doom.

[Kinsie]

Note Self: Use this sky trick to make a map that's deliberately, intentionally broken in GL, point at this thread when people complain.

[Zeberpal]

Note Self: Use this sky trick to make a map that's deliberately, intentionally broken in GL, point at this thread when people complain.

That's not a right focus. It was deliberately and intentionally made to show which (exclusive) feature zdoom engine has and other game engines don't.
Just tried to point out gzdoom could be a tool for something-something 3d avangarde, as it is trendy. It could get an attention to engine. Seriously.

I consider this mostly pointless. It won't look good, only has use for edge cases. I have more important things to do

I'm defendless here. I'm the only edge case so far :< Can only hope this idea will be a continuation for other modders to expand.

[Graf Zahl]

How did you even manage to have no sky displayed whatsoever in GZDoom? Normally the regular sky should be used, albeit wrapped around a dome-like shape.

[Zeberpal]

How did you even manage to have no sky displayed whatsoever in GZDoom? Normally the regular sky should be used, albeit wrapped around a dome-like shape.

Sorry, I don't really understand. If you mean, why that sky won't render properly in Gzdoom...In Gzdoom case, it happens when two or more sectors with different skies are close or adjacent to each other.
To reproduce this try to run attached file in software and OGL modes.
That's the thing. I could probably simulate flat skies with acs and camera hacks(which would not worth the effort, though) , but it would not render correctly after all anyway. It's glitchy, sometimes sky dissapear or won't appear at all. It really looks like a bug, to be honest.

[JimpArgon]

Zeb. I re-downloaded the file because I seen the original post had been edited today. Went to drag and drop (as I did with your first release.) and nothing happens. It just loads up stock doom 2....

Is there something wrong with the file?

[ibm5155]

what could be done is a 3D model around the skybox viewpoint, and limit the up/down view angle so the player will not see the missing part on the botton/top.
Or even a normal sector that has the format of an circle and the câmera on the mid of it.

[Zeberpal]

This is really just a half-measure, which would only work in very small amout of certain cases, or would not work at all. Besides as I explained earlier there is a problem with GZD not having a good time rendering two or more different skies which are close to each other.
When I was making this thread, I thought that sewing flatskyrender feature into GZDoppengl would also fix this bug i just point out.