ENB experts: What causes this lightsource bloom effect?

[Asterra]

It's not ENB's default bloom setting in any respect. It's not any of ENB's primary settings. It's some kind of secondary effect. And because it seems to be something done by default with the ENB presets that use it, no control is given over how it works. It's just always there.

(This is for ENB for Fallout New Vegas / Fallout 3, but I've seen similar circumstances in other games.)

Here is what a hanging lamp looks like with lighting set to 0.0, in an ENB preset which lacks the bloom effect:



And here's the same shot, also with lighting set to 0.0, using an ENB preset which has the effect:



I basically have two questions.

1: What part of enbeffect.fx should I be trying to scavenge in order to transplant this effect? I thought I tried everything, but frankly I find the file fairly inscrutable. It's not LUT, it's not nightvision, and it's not any of the Kinematics.

2: The effect has an annoying artifact that can only really be seen when moving the camera subtly. It's as though the light being generated by the effect is shining through a pane of stained glass, reducing the glare to a series of individual squares with a total resolution on the order of, say, 480x270. Here, this is what I'm talking about: https://youtu.be/CzO2aDw4Gkc
(Unfortunately, the effect resembles compression artifacts a lot so it can be hard to discern after being compressed twice. You can definitely see it if you watch this spot, though:

You can see how the blooming effect seems to be a construction of individual large-ish squares that come and go as the image makes subtle changes, creating a sparkly effect. This sparkly effect is sort of a dealbreaker. I'm hoping somebody has an idea of whether the resolution of the squares can be lowered, or something, so that the artifact can be reduced or eliminated.

[ENBSeries]

It's bloom or lens effect. To avoid pixel artifacts in it's shader texture reading should be done by bicubic filtering (or any other better than bilinear).

[Asterra]

I figured out the lightsource blooming is being enabled by some custom tonemapping. I've already transplanted it and gotten some results.

The lingering issue is that low-res squaring artifact, which seems to only become a problem when the tonemapping enhances light. (It's always there, but almost unnoticeable under previous circumstances.) I got no clue where in the code anything is being calculated as bilinear or otherwise.

Here's a better illustration of the problem than my dumb video showcased:



Somewhere, the light is being calculated at a low, square-shaped resolution. The square sides travel with the illuminated objects. The resolution of the square matrix seems to be about 1/5th of the native resolution—5 native pixels for each "pixel" of the square light matrix.

(Actually the tiny line in the upper right of the image might be the best example. You can see the squared-off glow around it, and how it's essentially a stationary vertical rectangle despite how the line changes position.)