Hi, my project at the moment is something akin to a game in which you fly around in a plane, or helicoptor. You fly around, not too fast, the camera is a set a little behind the craft you fly. I want the world to be pretty. I want the sky to be pretty, as you will rarely see the ground. I imagine having pretty, whispy clouds. with this in mind, the options I can easily imagine are: 1/ Sky box with the clouds. The sky box would have the textures animating slowly over them, to give the impression of wind on the clouds. However, in my game you can''t see all the way to the end of the world, so the skybox and its clouds would be invisible for much of the time, which means no clouds. However for cut scenes, This would be an excellent method. 2/ have 3d objects as my clouds. However, the world is fairly large, and I can only imagine i would need alot of these 3d objects. Perhaps generate them dynamically would be the idea. I think i could do that. Also, there would need to be several different cloud models otherwise it would become repetative. However, I don''t think I could make a 3d object look cloudlike, although with some alpha blending perhaps i could, not a real artist here :-) 3/ I have no other idea on how to create clouds for my world. The very best thing I can imagine is something along the lines of opneGL''s fog. But a localised version. As I understand it, opengl''s fog is either on or off. If it''s on, the whole scene is affected by the fog. But if the fog could affect only a small area, that would be the prefect thing for my needs. Has anyone seen anyone else working on soemthing like this, and how they dealt with it? Thanks for any suggestions.

Perhaps some kind of particle system would be a good way to do it? If you set the blending modes / particle velocities correct they would look rather realistic. Plus you could have your particle system be affected by wind so it looks more realistic. Also that would allow you to do things like when you fly through the clouds it stirs them up, sort of how rockets in UT 2003 stir up smoke.

NeHe just wrote a tutorial on volumetric fog... Read it!

James, I did so.

However, it appears that volumetric fog is tied to actual geometry, where I would require this cloud or fog to float in the air, not actually tied to any polygons.

I believe that volumetric fog as described by Nehe can not be used as simply floating clouds of fog.

Please correct me if I am wrong, becuase it would be great if it was of use for this.

Bah!



Doesn''t matter, I realise now what someone else said in this thread, this fog is a blending method, so the fog would have no effectover invisible poly''s.

I am trying a way to do nice whispy clouds you can fly through and see from afar, as per a real cloud, and this seemed a way to do it, but it clearly isn''t.

This is really foxing me.

Use a skydome instead of a box and put several layers of perlin noise generated cloud textures over them. Go take a look at the Graphics programming & theory forum. There is an *excellent* sky renedring thread by Yann L. there. (do a forum search for it)

Sander Maréchal
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Yann Clouds Thread:
http://www.gamedev.net/community/forums/topic.asp?whichpage=1&pagesize=20&topic_id=86024

Do a search for Mark Harris, he has a cloud paper that does exactly what you want(fairly complex though...)
Jesse

For the actual sky box - i would consider using a skydome that is permanently centred around the camera, i have used this in my game and think it looks good.

feel free to have a look

www.brownmonster.co.uk

Bargh. Some people just dont understand that a sky box doesnt actually SURROUND your ENTIRE world. It can be significantly smaller if thats what you want. You disable depth testing, draw the box around the camera, re-enable depth testing, and draw everything else.