2D skybox brightness

[SteveL]

Happy New Year everyone. I read Sotha's skybox tutorial and made myself a cubemap of a wooded hilly backdrop in Terragen. It renders lovely in game, except that it's too bright and saturated. I adjusted the lighting and colour in terragen for a bright moonlit scene, so the land looked right -- darker than the sky and with desaturated colour. But when put in in game the non-black parts of the scene gain a lot of saturation and brightness. Ambient light doesn't seem to have an effect -- or at least, moving my skybox in and out of the range of my ambient_world light doesn't affect it, and my ambient_world is set to only 8.

 

All that makes up my test skybox is an info_portalsky surrounded by a cube of caulk brushes with my cubemap on the inside surfaces. I have no light in there that I could dim or remove :-/

 

Is it one of these parameters in the material file that's adding the illumination? I copied these from the tutorial, but I haven't been able to find out what "texgen skybox" does, for example.

 

textures/skies/custom/yoursky
{
qer_editorimage   textures/custom/skies/yoursky.tga
noFragment
noshadows
nooverlays
forceOpaque			// so transparent windows can draw on top of it
{
blend	  add	  // so transparent windows can draw on top of it
cameraCubeMap   env/custom/yoursky
forceHighQuality
texgen	  skybox
texgen		 wobblesky .0 .0 .0
}
}

[Sotha]

Maybe re-touch the skybox texture files with gimp and tone the brightness down?

[SteveL]

Apologies, I started to test your advice, but now think the problem is due to some kind of graphics config problem my end. I started by changing one panel of my cubemap, and so as to have something to compare, I took a screenshot in game to load into GIMP alongside my cube texture. The screenshot had a very similar colour profile to the original tga -- in other words, it looked right. But it wasn't like the colour I see in game, which was still brighter/more saturated. Then I accidentally closed TDM and while it was not running, the original scene in Terragen got the additional brightness and saturation too! I've seen this effect before: having TDM running in the background darkens all my other windows, but not when TDM has the focus. So you are right, I do need to reduce the brightness/saturation of my renders, and I need to do it without TDM running.

[rebb]

Alternatively to adjusting the images, you can try putting something like

rgb 0.75

into the cubeMap stage of the material, that should darken it.

 

Since it sounds like you are trying to tie your skyBox into the global Ambient Level, you might even be able to include it like this :

red ( global2 * 0.75 )
green ( global3 * 0.75 )
blue ( global4 * 0.75 )

 

The 0.75 is just an arbitrary value and can be anything, or dropped completely.

If you want to have the skybox show even at very low global ambient values, you can also add some arbitrary value on these lines.

[SteveL]

Thanks, that sounds really useful for tuning the skybox. I have no idea about material files though, and the wiki doesn't help much. When you say "the cubemap stage" do you mean you put that property in the same block as the cubemap property in the material file quoted above? And are global2/3/4 to be substituted with some particular name, or are they global names already defined somewhere for ambient RGB levels?

 

I guess I should test it... Thanks again

[rebb]

global2-4 are the actual names of the variables, mapping to the global ambient RGB multiplier values.

 

Just taking your example material from above :

 

textures/skies/custom/yoursky
{
 qer_editorimage   textures/custom/skies/yoursky.tga
 noFragment
 noshadows
 nooverlays
 forceOpaque                     // so transparent windows can draw on top of it
 {
   blend     add     // so transparent windows can draw on top of it
   cameraCubeMap   env/custom/yoursky
   forceHighQuality
   texgen    skybox
   texgen           wobblesky .0 .0 .0
   red ( global2 * 0.75 )
   green ( global3 * 0.75 )
   blue ( global4 * 0.75 )
 }
}