Addressing this low priority TODO task T71898: Grayscale BMP output files are 24-bit, not 8-bit
This change makes it so exported bmp's come out at 8bpp instead of 24bpp, cutting file size by two thirds.
This was a little more complicated than you'd expect because the BMP spec expects that 8bpp files use a color palette, so we have to spam out a color palette that is just every grayscale value.
On the cleanup side, I thought things read nicer with underscores rather than running the words together in lowercase. How it was previously didn't seem in-style but I've only looked at a very small portion of blender C code. I also removed some hyperlinks in comments that are now dead.
I've attached an exported file with these changes in place.
I'm not 100% sure if this is a good idea because not all image viewers can import it correctly, in particular Windows' default image viewer Photos. Here's the testing I tried on my Windows 10 machine.
works in:
- blender import
- irfanviewer
- gimp
- renderdoc
- imageglass
- visual studio 2017 (it actually has an image viewer built into it??)
- chrome
fails in:
- Photos (default Windows 10 image viewer for this type)
- Paint
- Paint 3D
Happy to let this sit until Bcon1.
