making skies like this :

monkeycracks · Post by **monkeycracks** » Fri Jul 20, 2007 1:47 am

...i hate you
lol
thanks for the help with the pixel stuff earlier
im too tired to comprehend anything right now though
SP away.

bitplane · Post by **bitplane** » Sun Jul 29, 2007 9:14 am

finally got round to taking it outside this morning...

I took a couple of images (with my phone), mixed em together in gimp, used filters->distort->polar coords thing to unwrap...

and ended up with this:

not bad for a first attempt! gonna get my real camera back and try some higher quality ones. I'll have my eye on the skies for interesting cloud formations from now on!

JRowe47 · Post by **JRowe47** » Sun Jul 29, 2007 4:03 pm

nice! I'm now wondering what other neat tricks can be found on other game dev /engine sites?

Good results, though!

deesine · Post by **deesine** » Sun Jul 29, 2007 6:59 pm

A follow up on the sky domes, there's something called light probes, from what I can tell they are about the same thing, though the light probe images are HDR, correct me if I'm wrong. I've used them extensively for sky rendering.

Light probe image gallery

There's also a prog called HDR Shop, which can be used to convert the probe images to vertical cross-cube.
(Link from the above site)
HDR Shop

I'll try to chip in with some thoughts on cube/dome rendering and how to get a decent looking horizon later with examples.

TheGameMaker · Post by **TheGameMaker** » Sun Jul 29, 2007 10:30 pm

I'm currently working on a Technik, using Tubulenced Perlin Noise to generate !!REALTIME SHADED!! Clouds...
The idea is simple: Use a 3D Perlinnoise, have coplanar planes going through it, and render this planes. For shading you now just have to do a Texturelookup for all the planes In the direcktion of Light (above\below) to find the amount of light, that will reach this point.
The problems:
1) Irrlich doesnt Support 3D Texture Lookups, so you would have to fake a 3D tex by 2D Textures, ergo you have eery plane to be individual.
2) You just may look from Below or above, otherwise it will look baaaaaaad..
the adventages:
1) Great looking
2)Realtime Generated

some Pics, of this technique (still done In MAX, so no Realtime.. sry)

then you still have to do a nice Looking Sky gradient, and everything would be fine... maybe^^
hope this will work out, as I want it to...
tgm

deesine · Post by **deesine** » Sun Jul 29, 2007 10:55 pm

This is similar to mayas' fluids, a bunch of planes with noise texturing. And considering that clouds are fairly elevated most of the time, the below-or-above problem should be much to worry about, unless you want to fly through them. Maybe some kind of billboarding effect could fix that issue.

TheGameMaker · Post by **TheGameMaker** » Mon Jul 30, 2007 12:41 am

yeah.. your totaly right.. the only "special" thing in real time would be the lighting... The Problem with billboards would be, that your cloud cover has large extends in 2 Dimensions, and in the high, its very small. So if you would use Billboards the amount of billboards facing up would not be necessary very high.. (about 10 looks good enough) but if their facing to the sides you would need a few thousand to fill the entire volume.. besides of this, the Billboards would have to shift their center depending on the angle of View (otherwise they would be all at the same XY coordinates, but with a little z Offset). This approach would work, if we have a single cloud, inside a more
or less box formed bounding box. (I was thinking about this too, but for a MAX plugin..)

omaremad · Post by **omaremad** » Mon Jul 30, 2007 5:15 am

This cloud stuff looked interesting so i modified my old volumeteric fur/ grass postprocessor and got some basic results, ill still have to code lighting and some extra prespective corrections but this is just a little start.

The cloud are voumeteric and are derieved from a 2d texture mappped on a sphere.

TheGameMaker · Post by **TheGameMaker** » Mon Jul 30, 2007 1:38 pm

Great work Omaremad!!
Looks fantastic.. It actually looks like you got the lighting to work (pic1 the shadow...)
I wonder if your volume scenenode is opensource.
greetz tgm

omaremad · Post by **omaremad** » Mon Jul 30, 2007 2:11 pm

Currently there is lighting but thats derievd from the sky sphere, there is allot of work to be done on it so i wont release now (my old grass is ready so i can give that to you to look at it). I guess our methods are sorta suited to diffrent things, mine being nice on planets (who knows it might work nice if view from the inside)

My technique uses sevral assumptions and the opposite of what people do achieve bumps, maybe it works like hypertexturing? the resuluts are really similar:

Hyper texture

http://www.noisemachine.com/talk1/10.html

My grass/fur:

Crysis uses a very simple method for shadows and lighting, 2d billboard/ sky spheres are used but to fake volume a very smart lighting technique is used You can have a look on it here:
http://developer.download.nvidia.com/pr ... Crytek.pdf
(works on shader model 2 look for the clouds part in the middle of the pdf)

omaremad · Post by **omaremad** » Mon Jul 30, 2007 2:15 pm

Btw hyper texture isnt realtime

Virion · Post by **Virion** » Mon Jul 30, 2007 2:42 pm

omaremad wrote:Btw hyper texture isnt realtime

as long as it looks cool.

TheGameMaker · Post by **TheGameMaker** » Wed Aug 01, 2007 12:49 am

well, I saw hypertexturing in the "make noise blog thingy, but to be honest, I still don't know what exactly it is... (volume-visualization??)
I tried the thingy in real time now.. (in Rendermonkey, not in Irrlicht..)
and although it has a big fat bug in the lighting, it works very well with 16 layers without recognizable framerate hit... (sry.. no screens jet, there is this lighting issue)
tgm