Production quality special FX (??)
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- Gnoblar
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Production quality special FX (??)
I've been working on some 3D rendering special effects that I'm considering testing/implimenting into OGRE. Here they are:
Low impact model-to-environment soft shadowing
Highlight glow/glare effect
And in summary:
Low impact model-to-environment soft shadowing:
Models casting soft shadows from dynamic lights onto their environments. As far as models casting shadows on themselves, a simple stencil buffer would suffice (since most models aren't large enough to warrant soft shadows (the distance from an arm to a chest, for example, doesn't reveal very soft shadows, now does it? )). Basically, it would be (relatively) low impact on CPU speeds. I'm ignoring per-pixel lighting as an effect because it's incredibly intense on the GPU, as well as the fact that a lot of older (ok, circa Geforce2MX) video cards wouldn't be able to support the shaders (not all of you care, that's ok). Basically the algorithm would cast (relatively)realistic soft shadowing from a lightsource to a model to the environment without a huge strain on either the CPU or GPU.
Highlight glow/glare effects:
A scene specific glow effect that is visible (for example) in any normally lit photograph. Nothing dramatic, but a suble glow effect around any glaring surfaces in the scene, and automatically applied to the entire scene. This is not a replacement for light glows or lense flares, but more as an accent for an entire scene.
Let me know if anyone is interested in my experimenting/testing/implimenting either of these algorithms into the OGRE source.
soniCron
Low impact model-to-environment soft shadowing
Highlight glow/glare effect
And in summary:
Low impact model-to-environment soft shadowing:
Models casting soft shadows from dynamic lights onto their environments. As far as models casting shadows on themselves, a simple stencil buffer would suffice (since most models aren't large enough to warrant soft shadows (the distance from an arm to a chest, for example, doesn't reveal very soft shadows, now does it? )). Basically, it would be (relatively) low impact on CPU speeds. I'm ignoring per-pixel lighting as an effect because it's incredibly intense on the GPU, as well as the fact that a lot of older (ok, circa Geforce2MX) video cards wouldn't be able to support the shaders (not all of you care, that's ok). Basically the algorithm would cast (relatively)realistic soft shadowing from a lightsource to a model to the environment without a huge strain on either the CPU or GPU.
Highlight glow/glare effects:
A scene specific glow effect that is visible (for example) in any normally lit photograph. Nothing dramatic, but a suble glow effect around any glaring surfaces in the scene, and automatically applied to the entire scene. This is not a replacement for light glows or lense flares, but more as an accent for an entire scene.
Let me know if anyone is interested in my experimenting/testing/implimenting either of these algorithms into the OGRE source.
soniCron
- staringmonkey
- Greenskin
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Well, these both sound interesting, but you should know that shadows will be (as I understand) Sinbad's focus for the 0.14 release. I think the other (glow) is a little too implementation specific to be a part of the engine itself, but could be cool, shall we say, "for the sake of being cool."
staringmonkey
staringmonkey
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- Gnoblar
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- staringmonkey
- Greenskin
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Hehe, well I'd be the last person to describe myself as a hardcore Ogre developer (or maybe that's nieve as it's almost all I do with my free time right now ), but as it goes I advise you to dive in and see what's being done, their are a lot of very very cool additions/plugins/tools being written at the moment, but their is certainly room for any quality addition. Best of luck with it.
staringmonkey
staringmonkey
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- Gnoblar
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- sinbad
- OGRE Retired Team Member
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From the work that I've seen, accurate softshadows (the kind that use a shadow volume) are still slow even on the current top-end cards. Projective textures give the nicest averagely accurate effect for low overhead although they have limitations, they're my favorite practical shadowing approach. Shadowmaps are more accurate but don't look as nice. Stencil shadows are ok but look very artificial. 0.14 will allow all of these except the volume-based soft shadows, because the realistic performance you get out of them right now just isn't worth the effort - if no-one can use them in any real-life product then theres no point, I'd rather wait a year or two until gfx cards catch up and can do them at practical speeds.Basically the algorithm would cast (relatively)realistic soft shadowing from a lightsource to a model to the environment without a huge strain on either the CPU or GPU.
- Kencho
- OGRE Retired Moderator
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Well, Sinbad, as far as I know, volume textures and shadowing is not as hard... plus you have many effects at the same time, as you can make some materials translucent (project the shadows in the back side), draw the light shafts, and the most important, shadows!
I think that the new material framework will help on this...
Anyways, visit http://www.cgshaders.org to see some samples of what I'm saying ^_^
I think that the new material framework will help on this...
Anyways, visit http://www.cgshaders.org to see some samples of what I'm saying ^_^
- sinbad
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Yeah, I'm quite familiar with www.cgshaders.org thanks. Pity it's not updated any more though, it's showing its age.
I think you'll find if you actually try to use some of those effects you'll see they are not quite the panacea you might think they are. Texture-based shadows like the one in the 'misty room' demo are fine at short range but really show their inaccuracies at longer ranges - that's why the demos are always in very small enclosed areas. Shadowmapping and projective textures suffer from this problem too. To use them you need to have relatively short shadows otherwise artefacts appear.
Stencils can do longer shadow ranges but aren't soft, unless you use techniques as described here: http://www.ce.chalmers.se/staff/tomasm/soft/ - this research is looking very interesting, except that even on my FX 5900 it still runs far too slowly to be practical - given that the average card spec is lower than that I prefer to wait until it can be done well on most people's hardware.
All this comes down to needing to supply a number of shadowing options so people can choose the best one for their situation.
I think you'll find if you actually try to use some of those effects you'll see they are not quite the panacea you might think they are. Texture-based shadows like the one in the 'misty room' demo are fine at short range but really show their inaccuracies at longer ranges - that's why the demos are always in very small enclosed areas. Shadowmapping and projective textures suffer from this problem too. To use them you need to have relatively short shadows otherwise artefacts appear.
Stencils can do longer shadow ranges but aren't soft, unless you use techniques as described here: http://www.ce.chalmers.se/staff/tomasm/soft/ - this research is looking very interesting, except that even on my FX 5900 it still runs far too slowly to be practical - given that the average card spec is lower than that I prefer to wait until it can be done well on most people's hardware.
All this comes down to needing to supply a number of shadowing options so people can choose the best one for their situation.
- Kencho
- OGRE Retired Moderator
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- Gnoblar
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more shadows
Hey dudes,
http://developer.nvidia.com/object/fast ... lumes.html
This is the most interesting shadow implementation that i've seen, in terms of its performance. This is the only shadow volume that actually runs well on my card BTW, what about the shadow volume used in Doom3? Didn't John Carmak say the game was originally written for running fine on Geforce3? What does he do differently to make it possible?
Beers!
http://developer.nvidia.com/object/fast ... lumes.html
This is the most interesting shadow implementation that i've seen, in terms of its performance. This is the only shadow volume that actually runs well on my card BTW, what about the shadow volume used in Doom3? Didn't John Carmak say the game was originally written for running fine on Geforce3? What does he do differently to make it possible?
Beers!
- kfoong
- Gnoblar
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I found this a while back, might be useful:
http://www.maxjoi.com/keen/misc/GoldenGlobe.zip
too bad its in delphi
http://www.maxjoi.com/keen/misc/GoldenGlobe.zip
too bad its in delphi
- Keen
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- Gnoblar
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Just remember, opacity-wise, less is so much more. You don't want to end up with a Photoshop-esque, 100% opaque lens flare that just looks like it should be out of a low-budget sci-fi TV series. You probably want to play down the corona, have a little streaking (sharp needles of light pointing to the centre of the light) and banding (blurred lines of light eminating from the centre of light) and have a little (emphasis on the little) bit of flaring/rainbow pattern. There's a lot of information out there on the Internet about lens flares but, judging from Google, quite a bit of it is talking about the Photoshop/Max-style lens flares which, if I was being picky, I would say are a little cheap as well.
Less is more and imperfection is closer to reality when it comes to lens flares, glows, blurring and fogging/mist.
http://www.sxc.hu/browse.phtml?f=view&id=114199
http://www.gamespot.com/xbox/action/max ... ml?page=29
http://www.gamespot.com/pc/action/maxpa ... ml?page=84
Less is more and imperfection is closer to reality when it comes to lens flares, glows, blurring and fogging/mist.
http://www.sxc.hu/browse.phtml?f=view&id=114199
http://www.gamespot.com/xbox/action/max ... ml?page=29
http://www.gamespot.com/pc/action/maxpa ... ml?page=84
//redux.
- Antiarc
- Greenskin
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