[Bf-committers] Color space issues in importers/exporters

[Antony Riakiotakis]

Hello, we have a bug report that claims our importers do not do any
sort of color space correction
for external assets, see https://developer.blender.org/T43025

The issue should be that most exporters presume srgb color space while
our material definition is in linear space.

I am not sure if the asset formats have an explicit color space in
their specification but if not we can assume srgb. In that case, we
should make sure to backconvert from srgb to linear when doing
material conversion.

A quick test importing and exporting an obj from blender has no
issues, but that is simply because blender just dumps the linear
material value to the file, so reimporting will have the previous
value.

A way to fix this would be to handle it RNA side assume that assigned
colors are considered srgb and convert them internally but this can
backfire. It might be better to take care of it in our exporter files.

I am sending this to the list because we have a few maintainers for
our various asset formats.