ArnoldShaderUI : Add presets menu for image.color_space parameter

[johnhaddon]

No description provided.

[johnhaddon]

Pushed one more commit to do the same for CyclesShaderUI, as requested in #5618.

[ericmehl]

Code all looks good, nice to add this to Cycles as well!

Arnold doesn't seem to have access to all of the color spaces Gaffer does - if I put in Input.ARRI.Linear ARRI Wide Gamut 3 I get a warning from Arnold that it can't make the conversion. After that it seems to silently default to ACEScg when choosing a color space it can't convert to. Even after restarting a render and flushing the caches.

I haven't been able to find anything that lets you get the known color spaces from Arnold. I find their documentation to be hard to navigate though, so maybe I missed it.

Arnold also doesn't seem to respect the OCIO environment variable, even when using an actual .ocio file like what ships with Gaffer.

I guess without a way to know what Arnold can convert, and without a way to tell Arnold about additional spaces, there's not a much better alternative to showing all color spaces Gaffer knows about? Is it worth finding a way to reduce the list to known good spaces? I'm not even sure what those are besides ACEScg, sRGB and Raw.

[johnhaddon]

Arnold doesn't seem to have access to all of the color spaces Gaffer does

Are you using an Arnold colour manager to match Gaffer? You can get one in the NodeMenu at Arnold/Globals/Color Manager/Ocio, and the default values there should make Arnold use the same config as Gaffer.

[ericmehl]

Ahhhhh, that's what was going on! With that all is well and LGTM.