"Emit Color" specifies emission color not depending on the diffuse color. "Ambient Color" modifies a color of the global ambient light that each material receives, and is used for the environment lighting instead of the diffuse color. If the ambient color is enabled, material preview uses global ambient color=(0.7, 0.7, 0.7) to get better preview.
These properties should be quite useful for NPR. I tried some test renders and indeed got much nicer results:
Also, this allows several importers/exporters to provide better support for materials.
The following things need further modifications:
- Game Engine
- COLLADA support
- Addons (importer/exporter and so on)
- startup.blend (material of the default cube)
I'm not sure if BLENDER_SUBVERSION should be bumped up.