Looking to make textures for Unity3d, and I'm stuck at what seems to be a simple stage. My goal is to create an RGBA image, with color information for every pixel, and a separate alpha channel. These two components get fed into Unity as base color and reflection strength, respectively. (Using "Reflective/Bumped Diffuse" material.)
If I use masking tools in Photoshop, I can erase parts of the output image (transparency). However, I would like to keep the original RBG color information when output, and not just have "blank" areas. Also, it would be nice if I could do it non-destructively, ie. the final alpha channel is dependent on a standard layer, or built from a path object, etc.
I have the same problem with The Gimp.
Any help on this would be greatly appreciated.
(If Photoshop/Gimp are not the tools for the job, can someone please recommend a better one?)