Over at steakunderwater.com (Compositing Forum. They use Fusion) a guy (Midgardsormr) Made an exponential glow.
First he states:
People ask for an exponential glow all the time. The available macro is slow, and it’s something I’ve been eyeing for a while as a Fuse project. I don’t have the best eye, though, so I thought I’d open it up for commentary. Attached is the current state of my fuse. It’s significantly faster than the macro. Fusion’s blur method is really good; I experimented with scaling the input image down prior to blurring, as the macro does, and as is suggested in a few articles on HDR bloom effects for games, but the two scales took longer than the blur itself.
(Thread: https://www.steakunderwater.com/wesuckless/viewtopic.php?f=17&t=3275 Seems you have to be logged in )
Those are the Adjustments one can make to the glow:
Mode : The Exponential mode spreads faster and generally has a less intense core.
Threshold : Values below the low end of the Threshold will not glow. Values above the high end will glow with maximum strength. There is a gradual falloff of glow strength from high to low.
Gain : Pre-process on the source image. This occurs after the threshold.
Source Saturation : Pre-process on the source image. It doesn’t affect the actual source image, but it does modify the color that is used to perform the blurs.
Glow Saturation : Strength of a progressive desaturation of the glow—colors will become more or less intense with each iteration.
Glow Size : The initial blur kernel size. X and Y glow kernels can be unlocked and adjusted separately if desired.
Iterations : The number of glows to perform.
Falloff : The rate at which the brightness of the glow decreases.
Gradient : The glow can be recolored with this control. The first iteration will be the color of the left edge, and the final iteration will add the color of the right edge. The gradient is additive, so you may not wind up with exactly the colors you’re expecting.
Glow Only : Turns off the Merge onto the original source image, leaving only the glows.
com.MuseVFX.XGlow.zip (5.3 KB)