Fog

Can anyone give me a short short intro to why games uses FOG?


- Is it because it is suppoesd to hide the objects far away, so it should render faster (don't think thats why)

- Or is it to hide the objects that you don't render far away due to space partitioning?

- Or is it to make it more "real" looking?

- Or is it simpley to ad fog to the terrain, if there is fog in the air...???

- Or is it any other reason?

Ow when you said FOG before I guessed it shood for something. I didn't realise you just meant fog. in that case its to limit the range the player can see. It also makes it nicer for not rendering out of range objects becuase they fade into the fog then you can safly stop rendering them and the player is non the wiser :D.

But if it makes it nice, and you are still rendering the things in the background, then it will actually be slower then not having fog...don't you agree?


But if you use a quad three and narow the rendering so you can actually see that some of the terrain is missing if you are on a hill top or something, maybe we can hide it with fog? Or maybe that will look weird with a skybox?? I have no idea here. Never used fog before...maybe we can test, or find an article that can answer it for us. Or maybe you know it...;)

The 3D sample I showed you before (think it didn't run on your box or something ? :confused:) used fog, it looks ok but the problem is it looks a lot better with a skybox and no fog.
SkyBox's and fog don't mix at all, otherwise the skybox would be hidden by the fog ;).
Fog is good for cutting down the load on the rendering but it comes with the consiquences of the player being limited in how far they can see.
As you said if we dont use fog then we can use a good render queue to keep the load down. It would be good if we could have fog that is set to a really big range but then the skybox wouldn't get shown :(.

Yeah, I was worried about the problem with skybox and fog at the same time...then we just better hope that the quad three does it job, so we never see that the terrain is cut off...:D

I don't think it'll be too bad, the ROAMing will have cut the landscape down to a couple of Verts at large distances and we might be able to get rid of textures and use solid color at distance blocks.

Not sure if ROAM has the ability to make fewer triangels in a terrain...but I found out that there is a new datastructure called ROAM 2 the other day...maybe we can make ROAM 3 and make it show fewer triangles..(MERGE) :D

Quote:

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Posted by NoteMe
Not sure if ROAM has the ability to make fewer triangels in a terrain...but I found out that there is a new datastructure called ROAM 2 the other day...maybe we can make ROAM 3 and make it show fewer triangles..(MERGE) :D

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I must have misunder stood those articles I read, they were generally about terrain rendering. I thought it was all about ROAMing.

It talked about you have a datastructure that will define the terrain in high detail (or at least using the points in it and drawing curves from them) then the actual model is basically made to match the data closly if the camera is pointing at it and its close and the furthe away it is the less detail is used. This is dont by joining triangles if its already at a high detail or splitting triangles if the camera is getting closer to it.

Was a really good article to read.

Hehe...maybe we havn't read the same...ok...was it one of the aricles I posted a link too...maybe I should read that one too...:D..

But of course it will work, it is just to find out what is near and what is far away. And the beauti is that we can also find out where is is useful to split it like in cuved geometry, becuase in flat land it is not so usefull..