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Skybox Shader

Posted: Sat Apr 28, 2012 9:09 am
by Infernis
I'm trying to make a Skybox. I've found enough tutorials on how to make one, but one problem remains. I want to have a clear blue sky with moving white clouds. A good example of the effect I'm trying to achieve can be seen at 01:04 minute into this video.

I know I'll need a shader to achieve this and I could probably use a base shader from Quake 3 itself. So what's the problem then?

Do I need to make an entire blue skybox and have the shader refer to an image only containing the white coulds?
Which shader values do I need to use to achieve this?

I hope the above makes any sense. Any help would be appreciated!

Re: Skybox Shader

Posted: Sat Apr 28, 2012 12:57 pm
by obsidian
You'll probably only need one texture for blue sky and clouds. tcMod scroll takes care of the scrolling. An optional additive layer can be layered on top if you want a sun.

The rest of the shader (if you look at a basic Q3 sky shader - the q3map_, surfaceparm_ prefixed directives) takes care of the amount of light emitted by sun and radiosity, designates that it is a sky, no impact, etc.

Re: Skybox Shader

Posted: Sat Apr 28, 2012 2:44 pm
by Infernis
Thanks for the tips!
Would you also recommand using Terragen Classic to quickly generate skyboxes? Or do you prefer other programs?

Re: Skybox Shader

Posted: Sat Apr 28, 2012 10:25 pm
by obsidian
Terragen works, most 3D rendering programs, pretty sure Photoshop had a plugin as well.

Re: Skybox Shader

Posted: Sun Apr 29, 2012 5:54 am
by dONKEY
Hey.
Couple of things to consider. Do you need a skybox or will a sky shader do? If you need a sky box would a yadnar style 1024x1024 sky texture over a single colour skybox do?
You don't necessarily need to have a traditional 6 texture box.
If you are going for a single image sky or sky box choose carefully. Finding the right image takes awhile, and working on it to make it tile will take longer. At the risk of being shot down by the artist here, the 'make image tile' filters can save you a lot of time, but use with care.
Tiling the image by hand can give better results and after you have worked on a few textures you will begin to get the feel of which images lend themselves to tiling and which don't.

Re: Skybox Shader

Posted: Sun Apr 29, 2012 7:29 am
by Infernis
Hi dONKEY,

Well actually, I want to use this sky and then have if float over like in the video I posted earlier.