Like I mentioned in my previous post, in implementing my emissive mapping, I had a huge breakthrough that allowed me to fix my runtime glow mapping system to do what I had always intended.  While it provided a unique effect, the previous implementation had weird black borders that I couldn’t seem to get rid of and which prevented it from looking like the nice, blurred glow that I wanted.  The solution, it turned out, was very simple.

The fix was doing purely additive blending in my post processing.  Previously, I had figured that doing this would create an undesired effect were something to be a different color underneath.  Looking back, I have no idea why I thought that, it’s obviously wrong.  The original test I was performing was just to reject black pixels as a mask and layer on anything else over the final scene.  So, it should make perfect sense why there was a black band around the glow outlines; the blur created many pixels that were nearly black, but not quite, so they all passed the test and got layered in.  By switching to a pure additive system, the closer to black a pixel was, the less impact it had in the final composite scene.  And I finally had the effect I was after the whole time.  Like 5 months later.  I am smart.

This image was taken on 2/3/13.