Print
Achieving great realism through light and shadows
It’s all about light. Without light, you can’t see. In 3D games, all lighting is created using mathematical cheats—approximations of how real-world lighting behaves. Some of the most interesting lighting effects lie in the absence of light: darkness and shadows.
Shadows have evolved from simplistic shadow maps—where the shadows all looked the same from any angle—to the more sophisticated techniques used in today’s games.
Variations on ambient occlusion are becoming increasingly more popular. Ambient occlusion takes into account how light falls on objects to create shadows, and that the properties of light and shadows change over distance. Crysis was one of the first games to attempt a form of ambient occlusion, known as screen space ambient occlusion (SSAO). SSAO techniques try to determine where a point in the scene exists relative to other points, and the effect that light falling onto that point has on other parts of the scene. Objects have reflective properties, and may in turn bounce light to other parts of the scene—even those blocked from the direct light source.
Real-world objects tend to have crevices, wrinkles, and depressions, which may not be directly lit by a light source (the sun, for example). But they aren’t dark, either—they pick up light being bounced off other parts of the environment or even a nearby surface of the same object that is in direct light. Previous games often ignored this, so crevices and depressions were either completely dark or looked as brightly lit as the other parts of the object.
Other types of ambient occlusion found in newer games include high-definition ambient occlusion (HDAO) and horizon-based ambient occlusion (HBAO). These are still variations on the same idea—that where a pixel exists relative to other pixels determines how light falls on it, how it bounces that light, and what type of light it is (direct or reflected.)
Without Ambient Occlusion
With Ambient Occlusion
The circled areas in this DirectX 11 SDK example show how high-definition ambient occlusion (HDAO) produces more realistic details. Notice the increased depth, sharper lines, and greater shadowing.
Above is an HDAO sample from the DirectX SDK. Note the internal shadowing made possible in the lower screen by using this ambient occlusion technique. It is relatively subtle, but the overall scene seems more realistic when you’re running the application in full-screen mode. In the top shot, HDAO is disabled; the bottom one has HDAO enabled.
With DirectX 11, a new technique is emerging called contact hardening. If you think about how real-world shadows behave, you’ll realize that a shadow doesn’t look the same along its full length. Close to the object—say, at the base of a lamp post or tree—the line between shadow and light is sharply delineated (the “hard” in contact hardening.) The farther away from the object, the shadow is more diffuse. That’s because farther away, light seeps into the shadow area from the surrounding environment. Contact hardening shadows using Direct 11 graphics emulate this look. Right now, the only game using contact hardening shadows is STALKER: Call of Pripyat (below).
In this DirectX 11 SDK sample, shadows have harder edges near the object and softer edges farther away, as in real life.
Next page: Postprocessing Effects >>
Comments are closed on this article
jielg97
May 20, 2011 at 3:56am
In computer popular today, believe that daily life can't computer, natural cannot leave keyboard . http://www.laptopkeyboardshop.net/
liuyiyi
March 01, 2011 at 1:44am
Shop to provide quality professional value of the trust-level digital camera battery charger Online sales cheap jvc battery chargercomp global?and panasonic battery chargerdelivery of quality value of nikon battery charger the letter lazy ~! JVC GZ-HD40 Battery Charger JVC GZ-HD320 Battery Charger JVC GZ-HD300 Battery Charger JVC GZ-MC500 Battery Charger JVC GZ-MG155 Battery Charger JVC GZ-MG157 Battery Charger JVC GZ-MG255 Battery Charger JVC GZ-MG275 Battery Charger JVC GZ-MG330 Battery Charger JVC GZ-MG330B Battery Charger JVC GZ-MG330H Battery Charger JVC GZ-MG360 Battery Charger JVC GZ-MG365 Battery Charger JVC GZ-MG555 Battery Charger JVC GZ-MG575 Battery Charger JVC GZ-MG730 Battery Charger JVC GZ-HD620U Battery Charger JVC GZ-HD620BUS Battery Charger JVC GZ-HM300BUS Battery Charger JVC GZ-HM330 Battery Charger JVC GZ-HM320U Battery Charger JVC GZ-HM330U Battery Charger JVC GZ-HM330BUS Battery Charger JVC GZ-HM340 Battery Charger JVC GZ-HM340U Battery Charger JVC GZ-HM340BUS Battery Charger JVC GZ-HM550 Battery Charger JVC GZ-HM550U Battery Charger JVC GZ-HD550BUS Battery Charger JVC GZ-MG750U Battery Charger JVC GZ-MG750BUS Battery Charger JVC GZ-MG760 Battery Charger JVC GZ-MG760U Battery Charger JVC GZ-MG760BUS Battery Charger JVC GZ-MS110U Battery Charger Panasonic Lumix DMC-FZ35 Battery Charger Panasonic Lumix DMC-ZS3 Battery Charger Panasonic Lumix DMC-ZS1 Battery Charger Panasonic DMC-TZ5 Battery Charger Panasonic Lumix DMC-TZ3 Battery Charger Panasonic Lumix DMC-FX33 Battery Charger Panasonic Lumix DMC-FS3 Battery Charger Panasonic Lumix DMC-FZ7 Battery Charger Panasonic Lumix DMC-FZ50 Battery Charger Panasonic Lumix DMC-FZ28 Battery Charge Nikon EN-EL15 Camera Battery Nikon EN-EL14 Camera Battery Nikon Coolpix S8100 Battery Charger Nikon Coolpix S80 Battery Charger Nikon D2XS Battery Charger Nikon D3 Battery Charger Nikon Coolpix S210 Battery Charger Nikon Coolpix S220 Battery Charger Nikon EN-EL2 Battery Charger Nikon EN-EL4A Battery Charger Nikon EN-EL3A Battery Charger Nikon EN-EL9A Battery Charger Panasonic DMW-BCG10PP Battery Charger Panasonic Lumix DMC-ZS5 Battery Charger Fujifilm NP-45A Battery Charger Samsung TL220 Battery charger Samsung TL100 Battery Charger Samsung TL225 Battery Charger Samsung TL205 Battery Charger Samsung TL210 Battery Charger Samsung SLB-07A Battery Charger Panasonic Lumix DMC-ZS1 Battery Charger Panasonic Lumix DMC-ZS5 Battery Charger Panasonic Lumix DMC-ZS7 Battery Charger Nikon Coolpix S70 Battery Charger Panasonic PV-GS29 Battery Charger
lihong
October 05, 2010 at 1:03am
<p>It is no double that you can buy <a href="http://www.ghd-straighteners.com/"><strong>GHD straighteners</strong></a>. <a href="http://www.ghd-straighteners.com/ghd-iv-gold-styler-p-194.html"><strong>GHD IV Gold</strong></a> is very worth having them instead of going to salon. <a href="http://www.ghd-straighteners.com/ghd-iv-styling-styler-p-193.html"><strong>GHD IV Styler</strong></a> is so useful,and which you can take anywhere, because it is so convenient. Come on, you will get unexpected benifits from this hair straighteners.Besides, <a href="http://www.ghd-straighteners.com/ghd-pink-iv-limited-edition-p-181.html"><strong>GHD Pink Limited Edition</strong></a> is so great and wonderful, which can save your time to style your hair. You only spend less time, which can make your hair beatiful. Buy <a href="http://www.ghd-straighteners.com/products_new.html"><strong>Latest GHD Hair</strong></a> now, you can get discount price with fast free shipping.</p>
lihong
October 05, 2010 at 1:08am
It is no double that you can buy [url=http://www.ghd-straighteners.com/][b]GHD straighteners[/b][/url]. [url=http://www.ghd-straighteners.com/ghd-iv-gold-styler-p-194.html][b]GHD IV Gold[/b][/url] is very worth having them instead of going to salon. [url=http://www.ghd-straighteners.com/ghd-iv-styling-styler-p-193.html][b]GHD IV Styler[/b][/url] is so useful,and which you can take anywhere, because it is so convenient. Come on, you will get unexpected benifits from this hair straighteners.Besides, [url=http://www.ghd-straighteners.com/ghd-pink-iv-limited-edition-p-181.html][b]GHD Pink Limited Edition[/b][/url] is so great and wonderful, which can save your time to style your hair. You only spend less time, which can make your hair beatiful. Buy [url=http://www.ghd-straighteners.com/products_new.html][b]Latest GHD Hair[/b][/url] now, you can get discount price with fast free shipping.
lihong
October 05, 2010 at 1:06am
<a href="http://www.buy-suprashoes.com/">Supra shoes</a> even created a model with the X-games colorway, and needless to say, it was a hit. They say they don't do much to market their merchandise,<a href="http://www.buy-suprashoes.com/supra-strapped-grey-p-274.html">cheap supra shoes sale</a>,<a href="http://www.buy-suprashoes.com/">supra footwear</a>, but who says they need any more marketing?Their big clients are enough to prove that these things must be hella tight, <a href="http://www.buy-suprashoes.com/supra-suprano-dark-green-p-232.html">buy supra shoes</a>, <a href="http://www.buy-suprashoes.com/supra-skytop-ii-blue-black-p-119.html">supras shoes</a>, <a href="http://www.buy-suprashoes.com/supra-skytop-ii-blue-black-p-119.html">buy supra shoes</a>.
Wolfgang
July 11, 2010 at 3:54pm
Simply well put! I have owned my share of both manufacturers; back from the days of the 8MB Diamond Monster 3D and what mesiah is pointing out is completely true...
Settle down fanboys! I go with the best performance/efficiency/bang for your buck offerings that get the job done...whatever brand that may be.
Submitted by mesiah on Wed, 07/07/2010 - 5:44pm
Aparently you missed the point of this entire article. This was not a comparison of ATI vs Nvidia. This was a comparison of DX11 vs DX10. Yes, ati and nvidia were differentiated in the article because each companies cards respond differently to the added effects.
As far as driver stability goes, neither company has a clean track record for their drivers. Of course an Nvidia fan boy is going to claim he has never had a problem with Nvidia drivers. An ATI fan boy is going to do the same. Having owned my fair share of cards from both manufacturers, I can tell you that they both put out their fair share of lemons. But if you insist that Nvidias shit still smells like roses, I will remind you of their recent driver recall.
http://www.maximumpc.com/article/news/nvidia_yanks_19675_drivers_investigate_overheating_reports"
gothliciouz
July 09, 2010 at 9:59pm
dx 11 sounds pretty cool, now if only game developers will use them properly. beautiful games we will get.
Valek7
July 09, 2010 at 9:33pm
Generally speaking, I've had a lot of good experience with DX10 and only a couple of games (like Crysis) actually showed a noticeable decrease in performance over DX9. With everything else, it was either a minor boost or no change at all.
But, the one game that I have to tout is Flight Simulator X, which now runs like a scalded cat in DX10 mode and Windows 7 on a Core i7 920. I was able to increase the detail settings much much further than I could with DX9 and I'm getting more than double the frame rates! With DX9, I'm talking about low end detail settings and barely... I mean BARELY 20 fps. It was a joke, at best. With DX10... I now have plenty of the good detail settings (scenery nearly maxed, textures maxed, further view distances... you name it, all bumped UP) and I get 50+ fps consistently! It's like a whole new simulator! DX10 and FSX FTW!
zjone (not verified)
July 09, 2010 at 6:32am
nike shoe sunglasses,hangbag....cheap sale !welcome to http://www.voguecatch.com
gliscameria
July 08, 2010 at 2:54pm
First off, very good article. DX11 sounds awesome.
It's been a while since I've done photography, but I think you have this backwards:
"Stopping the camera down results in a soft blurry background behind the sharply focused image. Opening up the aperture brings the background into better focus. "
Bigger apertures capture more light but reduce the FOV. I always remembered this because nature hates us and has to make everything difficult.
//Glis
dracx619
July 09, 2010 at 5:03am
something that has confused me plenty. lets see i have to think about this, to get a nice DOF, i decrease the shutter and increase the apeture (lets more light in), to get a shot in full focus, i increase the shutter and decrease the aperture(less light in)... yep, you right, i think?
gliscameria
July 13, 2010 at 1:37pm
I'm drawing off of old knowledge here...
When you increase aperture you allow more light in, but you also allow light coming in from more directions, which will decrease your DOE. Back in highschool VisCom you usually make pinhole cameras, they don't need a lens because the aperture is so small, but the exposure has to be pretty high. It's always a nasty tradeoff. It would be cool to see if you show a reduced DOE for humans in the dark. Maybe it's harder to focus on stuff in the dark because the focus has to be much more accurate, like seeing your blurry clock (outside of fuzzy eyes).
//Glis
dracx619
July 13, 2010 at 3:23pm
screw all this, it makes my head hurt, lol. i gotta dust off my dslr and try it all out again
bran6141
July 17, 2011 at 2:24am
Chris Evans Workout as he trains for the release of Captain America.
samduhman
July 08, 2010 at 10:27am
So is it time to buy a DirectX 11 card? I've been weighting this issue for a couple weeks now. I have a 4890 but being a hardware junkie I'm usually in the market to upgrade some part/s of my PC. Would you suggest I go ahead or wait for the next generation of gpus? I want a 5870 but don't want to spend that much.
cahedler
July 08, 2010 at 5:51am
It's interesting to see the results from Call of Pripyat, which have the GTX 480 being outperformed by a significant margin by the 5870. Can anyone shed some light on why it doesn't perform very well in Call of Pripyat?
Scintor
July 07, 2010 at 5:12pm
I cannot offer direct side by side comparisons, nVidia vs ATI, but there appears to be a lot of traffic in various forums to call into question the lack of stability in ATI's drivers for their video cards. On the other hand, nVidia has provided rock solid drivers for each of their video cards I have owned over the years.
It is relatively easy to compare performance of each company's video cards by using hard numbers for frame rates, and it is not so easy to quantify driver stability, but word of mouth is not so good for ATI, so I'll stick with nVidia.
Thanks for the 411 on DirectX 11.
mesiah
July 07, 2010 at 5:44pm
Aparently you missed the point of this entire article. This was not a comparison of ATI vs Nvidia. This was a comparison of DX11 vs DX10. Yes, ati and nvidia were differentiated in the article because each companies cards respond differently to the added effects.
As far as driver stability goes, neither company has a clean track record for their drivers. Of course an Nvidia fan boy is going to claim he has never had a problem with Nvidia drivers. An ATI fan boy is going to do the same. Having owned my fair share of cards from both manufacturers, I can tell you that they both put out their fair share of lemons. But if you insist that Nvidias shit still smells like roses, I will remind you of their recent driver recall.
http://www.maximumpc.com/article/news/nvidia_yanks_19675_drivers_investigate_overheating_reports
K0BALT
July 07, 2010 at 6:41pm
I love Nvidia and would pretty much call myself a fanboy, but I will also admit any flaws within their products as well. The ONLY issue I have encountered was the one driver that disabled overclocking... which only lasted a few weeks. All I have had is Nvidia and can't really compare the two brands. I've always had Nvidia and have never run into a problem besides that one driver...which didnt affect me because I dont overclock my cards unless im benchmarking. Theyve treated me well and I know ATI makes good things too. Which is why I don't put them down. But... in the end I am a firm believer that Nvidia is overall a better product because of their technology and software in daily use. ATI is greats stuff, but I think Nvidia will reign supreme. It's like comparing Windows to Linux. Theyre both good, but one is more used than the other for a reason.
This is my opinion and I'm entitled to it....as are you. not trying to start a flame war. We're all here for the same reason, so let's be adults. MaxPC to all!
-------------------------------------------------------------------------------------------------------
i7 920@4.4GHz,Heatkiller 3.0, EVGA GTX480, EVGA GT240(PhysX), EVGA X58 3X SLI, 6GB DDR3 OCZ Gold @ 1770MHz
mesiah
July 07, 2010 at 10:38pm
Everyone is entitled to their opinions. That doesn't make them right. Just kidding :P No, I agree with you. There is nothing wrong with brand loyalty. There are definately products out there that I have a preference for. What annoys me is when people let their love for a logo blind them to any and all flaws in a product. Its blind love for a brand that has made apple so powerful as of late. They could put out a dog turd with an apple logo and people would eat it up.
I think this is a good article and I didn't want to see the comments get derailed into an Nvidia vs ATI dispute. They have both put out good solid drivers, and at times they have put out some barely functional steaming piles of poo.
