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jollyjeffers

Bloom filter for HDRI images

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Hi, For those familiar with real-time HDRI work, a common processing step is to blur/filter the HDR values and then add them back to the scene - giving bloom/star (etc..) filters.. Whilst the actual effects might not be physically accurate, they do seem to at least be close to the physical effects. My understanding, which might be the problem here, is that in real photography those effects are a product of the lens (and its optical properties) used to take the image(s).. Which, surely, should mean that all incoming light is subject to the same scattering/filtering effect. Either it's all just a general blur/bloom or it's all going to be a star-filter. ?? However, I saw a link for some PGR3 screenshots (XB360), one of which is the following:
(click to enlarge)
From the looks of that image, the general sky/sun light in the background (behind the distant buildings) is just a general blur; whereas the close-up metal work (on the car wheel for example) is a star-filter. That is, for one image, they're generating two different types of lens-related optics...?? I've been doing my reading on HDRI - and had a quick look at my reference material, and I can't seem to find anything that indicated whether that image is correct/wrong or if what I'm saying is true [smile] From past experience, you guys in this forum are the ones that know about this sort of thing [grin] Any ideas? Cheers, Jack

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Actually, the star effect is throughout the entire image, not just the car (As shown below):
Image hosted by Photobucket.com

Fwiw, in my opinion that's actually a fairly bad implementation of the bloom and glare effect. The sky is WAYYY too bright, and the star effect should be much brighter.

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Original post by Cypher19
Actually, the star effect is throughout the entire image, not just the car

My bad [headshake] - now you pointed it out, it's actually pretty damn obvious... I'm going blind, I'm sure!

Quote:
Original post by Cypher19
Fwiw, in my opinion that's actually a fairly bad implementation of the bloom and glare effect. The sky is WAYYY too bright, and the star effect should be much brighter.

Agreed. Presumably it's in work in progress, and the balance of those sorts of things usually comes down to artistic-tweaking, so it might well get changed before release [smile]

Cheers,
Jack

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Agreed. Presumably it's in work in progress, and the balance of those sorts of things usually comes down to artistic-tweaking, so it might well get changed before release


Probably not. Superpig's game has a huge amount of soft glare and softening in the image, almost purely as an artistic choice. Until we see a lot of games overuse it, it's going to be overused for a lonnng time :-(

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Original post by Cypher19
Quote:
Agreed. Presumably it's in work in progress, and the balance of those sorts of things usually comes down to artistic-tweaking, so it might well get changed before release


Probably not. Superpig's game has a huge amount of soft glare and softening in the image, almost purely as an artistic choice. Until we see a lot of games overuse it, it's going to be overused for a lonnng time :-(

I forget which "big name" in games/graphics programming said it, but they declared "HDRI bloom" as being the "next lens flare"...

Lens Flares were horrifically overused in some games [headshake]

Jack

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