Talk:HDR Skybox Creation

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HDR Shop no longer available

There links are all dead and it appears that HDRShop has removed the free version from circulation. Are there any comparable tools?

• Top shelf, nice job Jeff. --wisemx 14:36, 23 Nov 2005 (PST)

i made an hdr skybox by skipping Organize the skybox images into a single file then did each skybox texture one at a time so i didnt need to use splitskybox --User:ChoGGi

Yea, I made my skybox that way also, splitskybox is never needed really. --Hipshot 16:40, 21 Jan 2006 (PST)

Could you explain in depth what was not skipped? What I'm confused on is how you were able to put the different exposures into the single file. -- User:silentsteps 18:39, 27 May 2006

• I made a TGA as explained in the tutorial but HDRshop won't load it.

Heck it won't even load the dod:s source/example file. (just says error but no specific reason whats wrong) Also any ETA on the hdrsplit tool?--Bluestrike 15:24, 5 Aug 2006 (PDT)

• • I, too, cannot open the combined files. I used the GIMP, latest version, and a 2048x1536 .TGA. HDRShop says there is an error opening the file. It may be a slight format error, I'll check HDRshop's site, but it opened the single-side ones just fine. I'm trying to ask the HDRshop forums, but the thing is slow. --Gman003 18:30, 24 May 2007 (PDT)
    • I found a workaround. HDRShop doesn't open any .tga format I tried, but saving it as a .tif works. --Gman003 16:41, 9 Jul 2007 (PDT)

Okay, it's made...now...

How do you put it into the level? Would the name be in this case; sdk_sky_example or sdk_sky_example_ or what? And would it be possible to name the materials skyname_bk.vtf and skyname_hdr_bk.vtf, etc, so long as your VMT files were also made to match? Would you then call the skybox in the level editor through skyname or skyname_ or skyname_hdr skyname_hdr_ or what?

I'm going to be doing a few tests in 20 hours, after my monster Skybox finishes rendering, and if this isn't answered I'll post my findings.

EDIT: My test showed that I needed to use skyname_hdr_ in the level to make it work, which is perfectly fine by me. Call it by the HDR name.

Compiling the textures

OB's vtex doesn't compile HDR textures at all, and Ep1's outputs VTFs with the wrong exposures. Has anyone outside Valve successfully created an HDR texture? --TomEdwards 12:52, 6 Jun 2008 (PDT)

Wow thankyou for posting that, your right, Orangebox vtex doesn't work on these for some reason, but ep1 does! Thx a bunch for posting that.

BGRA8888 HDR texture format?

I've noticed that many HDR skybox textures use the BGRA8888 image format instead of, as stated in the article, RGBA16161616F. These VTF files are treated as LDR textures with an alpha channel by vtf2tga and VTFEdit, which output images with heavy color banding that are nearly transparent. I first thought it could be a wrapped RGBE color model, but the alpha/exponent values don't seem to be usable for this. Has anyone figured out how to export these textures into a proper LDR/HDR image format? --Barracuda 06:32, 13 January 2011 (UTC)

That's what you get when you make a compressed HDR texture. I suspect it's actually a new DXT-compressed format that VTFEdit doesn't understand. --TomEdwards 14:13, 13 January 2011 (UTC)

Ok, it's indeed influenced by the "nocompress" flag. And I could understand that VTFEdit doesn't support this kind of compression. But Valve's official tool vtf2tga doesn't seem to support it neither, which is quite strange. Too bad there's no public source code for vtex... could it be a proprietary compression algorithm? --Barracuda 15:00, 13 January 2011 (UTC)

Alright, figured it out! It's a fairly simple compression, the formular is: HDR color = RGB * (A*16). Then divide the RGB colors by 256 (for example, can be varied for the desired exposure) and you get the correct LDR image.

Source: SIGGRAPH 2006 HDR Publication, page 26.

--Barracuda 16:50, 15 January 2011 (UTC)

Nice one, I added it. --TomEdwards 17:46, 15 January 2011 (UTC)

pointsample 1

pointsample 1 // needed for compressed HDR skies, otherwise there will be harsh pixelation artifacts in-game. Don't use for uncompressed HDR

I just added this to the Creating Materials section. I've never seen it mentioned anywhere, but compressed HDR textures need point sampling enabled or else they'll look like this:

All of Valve's skies have the Point Sample flag enabled, you can test it yourself by disabling it.

Nukedrabbit95 (talk)