Why does bloom cause such a CPU hit?

[Guest]

In every other game I have seen bloom is a GPU function, so why does it cause such a massive CPU hit in FSX?

[victorwest2 0]

I think it's something to do with having to render the image twice.

[tohughes76 0]

I'm keeping my fingers crossed that the DX10 update will better allow for the use of bloom. Currently costs me about 5-6 FPS, which is just too much. Really looks great when it is on, though...

[Guest Lith1um]

Bloom, 2.x water, and shadows in FSX all require the video card to render an extra pass. In other words adding those post processing effects makes the video card render the same frame twice before it's displayed. The world is rendered, then the post processing effects are rendered. The 2 frames are combined in the frame buffer and then displayed as one frame with the post processing effects on the top layer.So basicaly it's an instant 50% performance hit.Phil Taylor posted about it in his blog, http://blogs.msdn.com/ptaylor/archive/2007...-fps-costs.aspxI just mentioned this in another post.Solar Eagle, are you Silly Eagle @ nvnews?

[Guest]

>Solar Eagle, are you Silly Eagle @ nvnews?>Check the screenshot thread there if you haven't, I posted a couple nice ones of Oahu island, and there's some interesting dialogue too. lol

[Guest]

Because FS has and most likely always will be an inefficient resource hog. Heck it can't even load textures on time.

[BobP 56]

I just read Phil Taylor's blog on the sliders and appreciate the choices. I do have a comment on the last paragraph:"You have to understand FSX and its performance as a Socratic, holistic thing across all the subsystems and how they interact. It

[n4gix 4,947]

>I just read Phil Taylor's blog on the sliders and appreciate>the choices. I do have a comment on the last paragraph:>>"You have to understand FSX and its performance as a Socratic,>holistic thing across all the subsystems and how they>interact. It

[Guest jshyluk]

He does put the Phil back into Philosophy, don't he? As far as I understand what Phil was trying to say - and I firmly believe the only reason I passed my Philosophy course in University was that the professor didn't want to have me back in his class the next term - is that the philospher Socrates would try to look at a problem by taking it up as a whole, whereas Aristotle the philosopher would try to solve problems by breaking them down into simpler parts, and attempt to solve each part on its own terms. As for bloom, I would suggest that the limits to it would fall into basic categories:1) How much of the game world that needs bloom is visible at one time. Think of a first-person shooter that takes place in a tight maze of hallways versus a view that encompasses many virtual square miles.1a) How many different textures in the visible area need their own bloom.2) How robust the user's PC is, including drivers.3) How talented/well-paid the development team is, and how crushing and dehumanizing their production schedule.4) Miscellaneous other, possibly including a detailed understanding of Classical-age philosphy.Jeff ShylukSenior Staff Reviewer, Avsim

[Guest Paul Middleton]

>whereas Aristotle the philosopher would try to solve problems>by breaking them down into simpler parts, and attempt to solve>each part on its own terms. >Indeed he did. Not that he ended up with simple explanations, unfortunately. :-('Now there clearly is something which is transparent, and by 'transparent' I mean what is visible, and yet not visible in itself, but rather owing its visibility to the colour of something else; of this character are air, water, and many solid bodies. Neither air nor water is transparent because it is air or water; they are transparent because each of them has contained in it a certain substance which is the same in both and is also found in the eternal body which constitutes the uppermost shell of the physical Cosmos. Of this substance 'light' is the activity -- the activity of what is transparent so far forth as it has in it the determinate power of becoming transparent; where this power is present, there is also the potentiality of the contrary, viz. darkness. Light is as it were the proper colour of what is transparent, and exists whenever the potentially transparent is excited to actuality by the influence of fire or something resembling 'the uppermost body'; for fire too contains something which is one and the same with the substance in question. .......etc..etc.' (De Anima, Book Two, Chapter 7)None of which, I'm afraid, sheds any "light" on bloom. Plato also used to talk about light.'At first, when any of them is liberated and compelled suddenly to stand up and turn his neck round and walk and look towards the light, he will suffer sharp pains; the glare will distress him, and he will be unable to see the realities of which in his former state he had seen the shadows; and then conceive some one saying to him, that what he saw before was an illusion, but that now, when he is approaching nearer to being and his eye is turned towards more real existence, he has a clearer vision, - what will be his reply? And you may further imagine that his instructor is pointing to the objects as they pass and requiring him to name them, - will he not be perplexed? Will he not fancy that the shadows which he formerly saw are truer than the objects which are now shown to him?' ("The Analogy of the Cave", The Republic, Book VII)Maybe Plato was thinking of light blooms, but he doesn't really help much, either. I'll shut up. ;-)

[Orlaam 306]

Forgive me for saying this, but why use Light Bloom? All the screens shots I've seen of it look neat, but in reality, unless you're looking through a greasy window, lights don't look like that. It just always reminds me of having awful vision or glasses on with Armor All all over 'em.

[Qatsimo 7]

Those who wear glasses have an advantage here, without loss of frames ;)Regards, Gerrit

[BobP 56]

Thank you everyone for your "interpretations". :) Perhaps years from now philosophical simmer's will discuss Phil's comments and meaning as part of simming folk lore. You know? like the real meaning of "Puff the Magic Dragon" or the actual words to "Louie Louie". LOL.All I know is that when I read Phil's summary, MY frame rates drop to single digits. LOL.Bob...

[PhilTaylor 45]

That is basically what I was trying to get across. You cannot just break it down and say "well you are light on shaders here and..." like I have seen some try to do. You have to consider the entire engine and its workload.With that in mind, FSX isnt really comparable to an FPS game with hand-tuned levels. We have a 15G db of world data and we ( and the engine ) never really know what is going to be loaded. It makes optimization interesting.And as someone said, 3 features require an extra pass:1)shadows2)water with reflections3)bloom.Those extra passes add up quick.

[Guest D17S]

Maybe, "Allegory of the Cave"? . . . one of my all time favs. Ever read Ralph Ellison's "Invisible Man"?. Same bloomin' idea, 2400 years later. Really enjoy'n these analogies.