Seeing a past pet peeve of mine discussed, I thought I’d chime in with some experience I had on the topic. Not sure if it helps with the discussion at hand, but these were my experiences with PBR and bloom in jme:
It’s been a while (as visible from someone’s screenshot in this thread), but back in the day when PBR support was still fresh, I spent a lot of time trying to get the default bloom filter to play nice with PBR materials. For dark or indoor scenes, GlowMode.Scene worked fine with enough tweaking, but for any kind of a daytime outdoors scene, it was almost impossible to get the bloom to not just turn into an overexposed blurry mess. Either it had too little intensity and was almost imperceptible or it just overexposed any remotely bright part of the scene.
In the end, I went with the following:
- MipMapBloomFilter from ShaderblowEX in
GlowMode.Objectsmode. I picked this one because I really wasn’t happy with the box blur the default bloom filter used to do in order to generate the bloom. The mipmap version instead uses mipmaps in order to generate gausian-like blur. - A copy of the PBR material definition that added the
Glowtechnique in order to support the Objects glow mode.
If I remember correctly, I even had plans to integrate MRT (multiple render targets) rendering into the shader in order to avoid a separate glow pass, but I don’t think I ever got around to doing that.
The last couple posts in this thread seem really similar to the frustrations I was facing at the time. Either the Scene glow mode simply does not offer enough control, or there is a severe lack of documentation/examples on how satisfactory results can be achieved. I do not remember why Nehon designed it this way, but from an artist’s perspective, jME’s bloom was (at least out of the box) rather useless when it comes to PBR workflows.
Side note: I wrote most of this post in past tense, as I haven’t actively worked with jME in a quite a couple years, but given how the last meaningful commit that affected BloomFilter.java was done over 10 years ago, I think I can safely assume nothing has changed.