Add a size/scatter parameter to CameraFrame.bloom

[animech-sijo]

The current implementation of Bloom has two parameters: intensity and blurLevel. They both have their purpose. However, I lack the ability to adjust the bloom size. While blurLevel could be used for such purposes, it feels more like a quality setting, i.e. how many iterations of blur. If I make the bloom "smaller" by lowering blurLevel, there's a sharp cutoff where the bloom ends.

Example of PlayCanvas Bloom, intensity set to 0.02 and blurLevel set to 5 (please look at the image against a dark background if using github in light mode, otherwise the cutoff is hard to see):

Unity has settings for Intensity and Scatter (i.e. size). Unreal also has settings for Intensity, and either Size for standard bloom or Scatter for convolution bloom. Below are screenshots of Unity's Bloom:

High Intensity, Low Scatter	Low Intensity, High Scatter

I'd love to see such a size parameter added to the built-in bloom. You want to be able to control Intensity, Size, and BlurLevel independently.