Alpha channel on skybox images / blending skyboxes - how?

[motorsep]

I was thinking about making 2-layer skybox (skybox inside of a skybox), where 1st layer (closest to player so to speak) would have mountains and whatnot, and the sky will be transparent, and the 2nd layer (behind the first one, farthest from player) would have clouds and I would scroll it.

 

Is it something possible to do out of the box? Any idea how material with transparent parts of the skybox would look like?

 

Is there any way to blend/transition one skybox into another? Like day skybox into night skybox ?

 

Thanks!

[Springheel]

You should look at the default portalskies included in many TDM missions.

[SteveL]

I had exactly this setup in a dynamic moonlight demo I did last year. I made the backdrop in terragen and split it into 3 layers so that the clouds could scroll in front of the stars and moon, but behind the landscape. The moonlight changed brightness depending on the could cover. That bit was a bit complicated too set up but the 3 layer split worked easily enough

[motorsep]

I had exactly this setup in a dynamic moonlight demo I did last year. I made the backdrop in terragen and split it into 3 layers so that the clouds could scroll in front of the stars and moon, but behind the landscape. The moonlight changed brightness depending on the could cover. That bit was a bit complicated too set up but the 3 layer split worked easily enough

 

Do you have map/material setup handy ?

[motorsep]

You should look at the default portalskies included in many TDM missions.

 

Portal sky doesn't work well with 120k x 120k open world maps (or rather it's very problematic to compile, and with all the hacks compiling such map takes more than half a day)

[SteveL]

 

Do you have map/material setup handy ?

 

The test map and materials etc are in this post, near the bottom: http://forums.thedarkmod.com/topic/16046-dynamic-moonlight/?do=findComment&comment=339487

 

 

Portal sky doesn't work well with 120k x 120k open world maps (or rather it's very problematic to compile, and with all the hacks compiling such map takes more than half a day)

 

Do you mean info portalsky, i.e. the skybox camera entity? What would you use instead?

[motorsep]

 

The test map and materials etc are in this post, near the bottom: http://forums.thedarkmod.com/topic/16046-dynamic-moonlight/?do=findComment&comment=339487

 

 

Do you mean info portalsky, i.e. the skybox camera entity? What would you use instead?

 

Oh, yeah, that map.. I though you are using portal sky (info_portalsky) on it.

 

I was talking about standard skybox - a room with skybox texture assigned. Several rooms inside each other, like Russian doll.

 

It could be done the way RAGE does it:

 

 

but it's more work than several skyboxes with alpha.

[SteveL]

I guess you could do it in a single material, with 3 cubemap textures either as separate stages or a single stage that uses 3 textures in its fragment program. But to get the cloud layer to scroll... that's tricky. You'd have to write a shader that incorporates the standard skybox (cubemap) texgen, and you'd have to pass in the player's view direction every frame as shaderparms. Then you use the view direction unamended to sample the foreground and background cube maps, and you'd apply a rotation to it for the cloud layer.