Thanks! I'll take a closer look at this when I have more time on my hands.

At a glance, it looks like this effect duplicates the bloom effect which is suboptimal from a maintenance perspective. If this effect doesn't require the bloom-related code, it should be removed.

It might also make sense to create a dedicatedLensFlarePass for theLensFlareFeaturesMaterial to implement lens-flare-specific configuration options in that pass. The pass would then be used instead of the internalShaderPass.

I'm also not sure about the duplicated luminance threshold and downsampling code. It would be better if the existing passes could be reused.

Thanks for reviewing! I agree with your points and will work on those changes.

Wow excited for this one, thanks@shotamatsuda for your work!