I think most here are familiar with additive blending. This is just addition of colors' components to simulate light.
RED (255, 0, 0)
+ BLUE (0, 0, 255)
-----------------------
= MAGENTA (255, 0, 255)
It can be used to make things glow when they overlap.
However I find that there are interesting cases, when one channel maxes out and the result is no lighter:
BLUE (0, 0, 255) + BLUE (0, 0, 255) = BLUE (0, 0, 255)
Ideally it would be nice if some of that extra could bleed over proportionately into the other channels
BLUE (0, 0, 255) + BLUE (0, 0, 255) = LIGHT BLUE (128, 128, 255)
Is there a known color mode of blending that describes this?
I don't think SFML has a way to do a custom blending like this but my idea is to not just blend RGB but to add to the overall light "intensity" as colors are added.