Is earth displayable in the Doom sky?

Has anyone ever successfully done a sky, featuring earth in it for Doom? Or is the "skybox" tech not advanced enough?

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There's no real obstacle to it. Depends where you want it positioned, though.

If you're mapping for Doomsday, GZDoom, or other OpenGL ports, you can use a standard cubic skybox. That'll allow you to have stuff in the sky right at the vertical of the player, instead of the cylindrical-or-hemispherical projection of the usual sky textures which can only cover the sides.

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You need four 256x128 patches to build into a 1024x128 texture with the name of the sky. One of them will have the Earth drawn on it.

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Can be done, but when viewed from Mars we're just one of the larger dots in the sky. Only really makes sense if your map's set on the Moon or closer.

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Dragonsbrethren said:

Sweet. I suppose that graphic would be vulnerable to freelook and f_sky cliffs, but its the only example I've seen that might work for the original engine/non-GL ports.

EDIT: clarity of formulation

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For sky cliffs, you just need to leave at least 72 pixels between the Earth and the top of the sky (assuming freelook is disallowed), though this may be too close to the horizon (100 pixels) for your liking.

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Foxpup said:

For sky cliffs, you just need to leave at least 72 pixels between the Earth and the top of the sky (assuming freelook is disallowed), though this may be too close to the horizon (100 pixels) for your liking.


If you get close enough to the cliff edge, I'm pretty sure that still would leave misalignments (the texture doesn't tile on Y) at the corners of the screen. Still, its workable. You could make a story concerning the fate of earth using that.

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Soundblock said:

If you get close enough to the cliff edge, I'm pretty sure that still would leave misalignments (the texture doesn't tile on Y) at the corners of the screen.

What are you talking about? Sky textures tile vertically the same way as any other texture: every 128 pixels, with a tutti-fruity effect if the texture is shorter than that. As long as the texture is 128 units tall, it will tile properly.

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Foxpup said:

What are you talking about? Sky textures tile vertically the same way as any other texture: every 128 pixels, with a tutti-fruity effect if the texture is shorter than that. As long as the texture is 128 units tall, it will tile properly.


Sure it'll technically speaking tile properly but unless the art is made to tile vertically, and it generally can't be once you include a horizon line, the sky would have an unnatural looking edge at the screen corners, once you're in an elevated position.

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That depends entirely on what you put on the horizon. If you're doing the surface of the moon, just make the sky completely pitch black (stars are not visible during the lunar day) and have the mountains fade to black at the bottom of the texture (which, if you're putting the Earth near the horizon, is astronomically accurate because the only places on the moon where the Earth can be seen on the horizon in its "traditional" (north = straight up/down) orientation is at the poles, where, due to the sun never rising far above the horizon, the pits of craters are constantly in shadow).

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Does vanilla complain if you use a sky texture taller than 128 pixels? I know in ZDoom, with freelook, you need a sky texture 544 pixels tall if you don't want any tiling, no matter what; though I guess 512 pixels tall should be enough in most case and might be easier to find (it's a power of two).

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Gez said:

Does vanilla complain if you use a sky texture taller than 128 pixels? I know in ZDoom, with freelook, you need a sky texture 544 pixels tall if you don't want any tiling, no matter what; though I guess 512 pixels tall should be enough in most case and might be easier to find (it's a power of two).

As I recall (it was a long time since I tested this), vanilla crashes on a texture taller than 128 pixels, though you can have patches extending past the bottom of the texture without problems, but the excess will be cropped out in vanilla Doom (though I've heard vanilla Heretic can use tall skies created this way). But it won't work in any case because the sky is aligned differently in ZDoom than vanilla (specifically, the horizon is at 200 pixels in ZDoom and 100 pixels in vanilla), so it's impossible to use the same sky texture for both and have it look right.

Fortunately, the TEXTURES lump overrides TEXTUREx in ZDoom, and is ignored by vanilla, so you can just define a tall sky in TEXTURES and keep the short sky in TEXTUREx.

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Foxpup said:

astronomically accurate


Simulation-level accuracy would definetely be secondary here, as long as the rendition creates a good illusion. I think most people (and, hopefully, stars) would forgive Doom's inherent 2.5D'ness for shunting pinpoint accuracy in favor of an interesting level design excercise.

In case you were wondering why I am bothering you with this, I am playing with the idea of creating a new level 11 for Doom2 - with all its story implications - finding the evil switch that must be pulled to save earth's population.

The exact pinpoint location for the level (moon, space station, holodeck, etc.) would likely be dictated by how convincing the available earth-in-the-sky rendition is, in regards to this plotline. If the map is ever started. The linked textures in this thread could potentially be used as base, unless they're heavily copyrighted.

I'd optimally like to have the option of squeezing some vertical drama out of the map while mapping (wall edges, cliffs, etc.), which is why I'm arguing the point...

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With regard to copyright, all photographs by NASA are public domain, so you can use/modify those to create textures without any legal issues, provided you credit NASA in your text file.

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Public domain means you don't even need to credit them. It's just polite (and helps people know that your texture actually are derived from public domain sources, I guess).

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/brushes off thread dust

I made a few new skies, and found 1024x512 to be the optimal solution, at least for ZDoom.

Here's the slice showing earth.



As you might spot I ended up modding the original id graphic, thx for all links/help.

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It looks promising! Would it be correct to assume that the level takes place on the moon, then? And...

Soundblock said:

I am playing with the idea of creating a new level 11 for Doom2 - with all its story implications - finding the evil switch that must be pulled to save earth's population.


...You should definitely go ahead with this, if you haven't already!

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Soundblock said:

Has anyone ever successfully done a sky, featuring earth in it for Doom? Or is the "skybox" tech not advanced enough?


Yeah Knee Deep in the Dead had a skybox converted from hawaiji view.

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