OSL : Vertex Alpha and Vertex Illum (Channels -1 and -2)

[lightcube]

OSL doesn't seem to have support to get the Vertex Alpha and Vertex Illum channels (-2 & -1). This means OSL cannot overcome the same shortcoming of the classic Vertex Color map that should also support these channels.

I would like to see OSL get native support for accessing all available vertex data channels.

[teratron]

You can plug an integer node into the map channel of the OSL UVW Channel node to access the negative numbered channels -2 for Alpha -1 for illum, and then you need another node if you want to split out the rgb channels.

This is pretty janky, we really need all this consolidated to one intuitive node with the channel names etc.

[teratron]

Can we just get a vertex color node with RGBA and Illum outs?