I'm looking for an image editing tool capable of editing images with alpha channels. I am working on a computer game and sometimes I need direct access to the R, G, B and A channels. I need to view them and edit them separately. The alpha channel is not always transparency. Sometimes it is a reflection mask, sometimes it is completely unrelated to the RGB image, and sometimes I need it to be completely black.
So far the only acceptable tool I've found is Photoshop. It can show each individual channel as a grayscale image and I can directly paint on it.
Most of the tools I tried don't even support alpha.
Some - Corel DRAW, Paint Shop Pro, etc. can only use the alpha channel as a mask - they have no direct editing capabilities.
The only one that came close to Photoshop is GIMP. But it is way too quirky. For example it always shows the alpha channel as transparency. If you have black alpha, then you can't see anything!
Do you guys know of such a tool? Hopefully free, or at least cheaper than Photoshop...