Alpha Sky Texture or Alpha Texture

[Tormentor667]

While working on one of my latest maps, I had a little idea and as I am not sure how complicated it is to achieve or if it is even possible, I just wanted to ask now. So what's my idea?

Imagine we have a map that looks like this now:

I never really liked the transition between the end of this asteroid and the skybox itself so I imagined something more unreal and different and came up with an idea like this:

Sure, right now this looks very odd but it could also work with one-color-floors, different skyboxes & walls and different flats (depends on how far this is possible).

I thought, how could this be done in an easy and maybe technically possible way, and so I came up with the "Alpha Sky Texture" (or Alpha Texture, whatever you like better.

I thought about creating a texture like this (also dependant to the mapper, this can be quite different):

...that's also defined in the ANIMDEFS as a special texture format

Code: Select all

alphatexture GRADIENT

maybe with other parameters depending on what's needed and what's possible.

Now using these textures would be quite simple: You just place lines directly in front of lines that you want to "fade", use the texture and voila, you're done:

Another possibility would be an ACS based solution but that would be more difficult but also more accurate. Nevermind, after doing this in DoomBuilder that way, the GZDoom ingame result would look like this:


So what would the engine have to do?
Simply draw the - by the image's white parts given - percentage of the skybox/sky or floor texture (horizonline style) instead of the "visible stuff behind it" (things, sectors, whatever lies behind). It would work exactly like LineHorizon, only that it doesn't draw this in 100%.

I can imagine that this is quite difficult for sector flats but I am almost sure that it shouldn't be too hard for Skybox-style Alpha Textures. Just let me know if something like this is possible. It would make up for great ideas and transitions in some places

[DaniJ]

If my understanding of GZdoom's current feature set is correct, this effect should already be possible. I'll however leave it as an exercise to figure out how since that is half the fun

[Rachael]

DaniJ, that's not how we do things here, this community forum is aimed towards being helpful towards people. Your post pretty much says to me "Yeah, you can do it, but I don't know how so I won't tell you."

I'm sorry if this is a bit more honest than you wanted to hear, but it's what I am seeing.

Additionally, as far as I am aware (Graf, correct me if I am wrong), what Tormentor wants is not actually possible yet. If you know how to do it, then by all means, let us know.

[Graf Zahl]

Without resorting to hacks, no. And I don't really know how to do it. The entire suggestion depends on very specific construction details to work. In most levels it wouldn't let the sky show through but random stuff that happens to be rendered behind the transparent wall, which is not necessarily the sky.

[DaniJ]

I didn't want to explain why I believe it to be possible because as you may or may not know, I'm a developer of the Doomsday engine and didn't want to step on anyone's toes.

However here goes:
GZdoom supports 3D floors so make the bottom of the asteroid a 3D floor with another sector below it which uses the sky flat for the floor.
Then add 3d mid textures to the linedefs which make up the edge of the asteroid and texture them with a copy of the material used on asteroid (the rock texture) but then add a linear gradient mask. Basically the exact same process as used for the light beams in the map already.

Yes it would require specific construction in the map itself but thats better than trying to get the engine to do this automagically whilst also considering skyhack walls etc.

[Graf Zahl]

Yes, that's probably the only way to do it. No matter how I look at this, there is simply no way to make this work as an engine feature.