Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

nothings.org

Post reply on HN
Print view View original

91–100 of 100 posts

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#91

Post by cindyllm »

inigyou wrote: post #89
Terr_ wrote: post #53

Earlier quoted context omitted.

Right, too many games pitch the "realism" of "really like a Hollywood movie", reproducing effects which are really telltale flaws in cameras, microphones, or the theater-experience. This is in contrast to the realism of "if you were there in person". If you step outside and look towards the sun and see lens-flares, consult an eye-doctor. If you see polyhedral lens-flares or bokeh... consult a roboticist.

I think you have to exaggerate certain things to get them over certain mediums. The lens flare isn't telling you the sun literally makes polygonal shapes. It's telling you the sun is fucking bright and it's dazzling you , and it's doing that by reference to something we've seen in films shot with cameras. You can achieve it other ways. HL2 Lost Coast - Valve's HDR tech demo - conveys the same basic fact by delaying t…

[dead]

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#92

Post by mananaysiempre »

inigyou wrote: post #83
mananaysiempre wrote: post #51

Earlier quoted context omitted.

I recall a GDC presentation about a physically-based atmospheric model developed for a (good) AAA game released sometime in the last decade, and it reportedly took up a noticeable part of the frame budget, so evidently you’re not alone in this opinion.

I'm not sure you would need that unless you're making a space simulator. Surely the model just spits out a color gradient which you might as well hardcode?

There are indeed precomputed LUTs, but apparently you need to be a bit more sophisticated than that if you want your sun angle to be dynamic, and they also did clouds: https://www.ea.com/news/physically-based-sky-atmosphere-and-....

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#93

Post by mfro »

gmueckl wrote: post #59
Maken wrote: post #56

Earlier quoted context omitted.

AO is an approximation of how indirect light behaves. If you have an actual global illumination solution you don't need these tricks.

AO is derived from full GI with some extremely crude approximations. Anything that simulates full GI more accurately is implicitly a more physically accurate replacement of AO. Still, AO is not dead because it is still a rather simple and cheap cheat to add more visual definition to concave corners and highly shadowed areas. Sometimes, artists decide that their scene should have this extra touch.

yes, this is something I have seen used to good effect, for example in the RE:4 remake

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#94

Post by 21asdffdsa12 »

Geee wrote: post #30
overgard wrote: post #7

I agree with his overall point, but I would point out: realism is not usually the point, the point is to look good. The problem with realism is once you get past "wow the computer can do that now", it's not very interesting -- most of reality is pretty dull looking!

I don't think this is true at all. I've been experimenting with a physical sky / atmosphere modeling, and it really seems that the most physically accurate sky is the most beautiful. I think this applies more generally to all light and shadows, and all natural effects which people perceive as beautiful, and at the same time difficult / expensive to recreate on a computer.

Golden hour light shining through leaves is literally the gold standard

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#95

Post by gmueckl »

inigyou wrote: post #84
gmueckl wrote: post #58

Earlier quoted context omitted.

One theme that is common to almost all visual art that strives for some form of realistic appearance is that they start out with real material appearances and physical lighting behavior. Both are inescapable parts of the reality in our physical world, anyway. By extension, this means that it is highly desirable to have a renderer capable of reproducing the real world as a baseline for highly controllable aesthetic tw…

If you want something realism-adjacent that makes sense. If you want to create Antichamber, which is a game about non-Euclidean geometry, maybe not. You can carefully try to match up the lighting on both sides of an invisible teleporter, but it's going to be much easier if your engine doesn't try to do lighting at all. (Antichamber is mostly flat colors, basic flat shading, and hand-drawn accents)

Approaches to stylisation different a lot. Feature animation works a lot with physically correct rendering as a starting point, for example. But when a hyper stylized look is the goal, approaches start to differ a lot. For example, algorithmically flat shading and outlining 3D characters to give them a manga/anime appearance is an art form in itself at this point.

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#96

Post by 21asdffdsa12 »

inigyou wrote: post #90
21asdffdsa12 wrote: post #80

Unrelated, but how would one fake splashing raindrops via a shader?

I'm assuming you can't see the actual splash but only the ripples it causes on a puddle, so maybe the surface of your puddle should displace what's under it by an animated noise texture?

Oh, the raindrops- in puddles there is something for that on shadertoy.

I thought about doing several 3d normal scales at pixel offset - and then do a animated "hair" texture on those layers..

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#97

Post by lesostep »

As an artist, I was taught that when dark area meets a lighter one, I should add a slight gradient, deepening the dark near light.

Is it realistic?

No. But it looks more realistic. Because as our eyes track across real room, they adjust to the brightness.

So the darker region would look much darker near a light region – not on camera, but to human eye. And we replicate that effect in drawing, to trick the nerve behind the eye into believing that our pupil adjusted.

That's it, I think. We are not cameras, and our realism doesn't look like a photo.

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#98

Post by tormeh »

This critique has accumulated some issues over time. Modern approaches like GTAO are way less intense than before. They essentially only add shadows to crevices. A normal corner like this will barely look different. More importantly, techniques like SSGI will correctly take color into consideration to darken black corners and brighten white ones.

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#99

Post by dcrazy »

inigyou wrote: post #89
Terr_ wrote: post #53

Earlier quoted context omitted.

Right, too many games pitch the "realism" of "really like a Hollywood movie", reproducing effects which are really telltale flaws in cameras, microphones, or the theater-experience. This is in contrast to the realism of "if you were there in person". If you step outside and look towards the sun and see lens-flares, consult an eye-doctor. If you see polyhedral lens-flares or bokeh... consult a roboticist.

I think you have to exaggerate certain things to get them over certain mediums. The lens flare isn't telling you the sun literally makes polygonal shapes. It's telling you the sun is fucking bright and it's dazzling you , and it's doing that by reference to something we've seen in films shot with cameras. You can achieve it other ways. HL2 Lost Coast - Valve's HDR tech demo - conveys the same basic fact by delaying t…

Lens flare effects have gotten decidedly more camera-like in recent years as other cinematic postprocessing effects have become common. You’ll see lens distortion and chromatic aberration along with aperture-shaped lens flares in many titles nowadays.

Re: Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion (2012)

#100

Post by Terr_ »

inigyou wrote: post #89
Terr_ wrote: post #53

Earlier quoted context omitted.

Right, too many games pitch the "realism" of "really like a Hollywood movie", reproducing effects which are really telltale flaws in cameras, microphones, or the theater-experience. This is in contrast to the realism of "if you were there in person". If you step outside and look towards the sun and see lens-flares, consult an eye-doctor. If you see polyhedral lens-flares or bokeh... consult a roboticist.

I think you have to exaggerate certain things to get them over certain mediums. The lens flare isn't telling you the sun literally makes polygonal shapes. It's telling you the sun is fucking bright and it's dazzling you , and it's doing that by reference to something we've seen in films shot with cameras. You can achieve it other ways. HL2 Lost Coast - Valve's HDR tech demo - conveys the same basic fact by delaying t…

> Lost Coast [...] This is also how your pupils work, of course.

As a purely temporal change it was neat, but I recall being distinctly annoyed with Lost Coast over how that effect made things worse (less realistic) for scene elements not under the crosshair / gun / avatar's-nose. We naturally expect contrast (and focus, see DoF rant) to improve when we direct our auto-adjusting eyeballs towards the area. In other words, realism of moving between light-environments came at the expense of realism in glancing around the room.

The straightforward fix would be gaze-tracking hardware... but now that I think about it (and with 20 years of tech improvements) I can imagine a much more mad-science approach: Track a simulated visual memory for the avatar!

Imagine a game that tracked recent virtual saccades to build up a cache of data like gaussian splats. So if that player has already seen the black notebook on the black desk in the dark room, it shows up more easily even if they walk in and out of the bright outdoors.

Post reply on HN