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» MEDIA (8) Figure 1: Object Overhead Reduction Figure 2: Improving Shader Processing Time With a Unified Architecture Figure 3: Crysis Comparisons Figure 4: Motion Blur Figure 5: Depth of Field Figure 6: Soft Shadows, Volumetric Lighting Figure 7: Who Doesn't Like Explosions? Figure 8: Atmospheric Scattering, Inclement Weather

Arguably the most anticipated and touted feature of Windows Vista is the newest version of Microsoft's computer graphics framework, DirectX 10. It promises performance many times that of the previous iteration, as well as unprecedented visual effects that may finally begin to blur the line between reality and its virtual counterpart. In this second half of my look at Vista and its effect on PC gaming, I shed some light on a subject of which many speak, but few know. Is DirectX 10 reason enough to upgrade? Read on and decide!

» WHAT IS DIRECTX?

DirectX is a collection of application program interfaces, or APIs. While the term "DirectX" actually encompasses many different ways for software to directly interact with hardware, common usage refers to the APIs used for graphics, namely DirectDraw and Direct3D. These are used by game developers to more easily create advanced visual effects without essentially having to re-invent the wheel, leaving more time to focus on content.

Built from scratch and utilizing Vista's new display driver model, WDDM, Direct3D 10 is not backwards-compatible with previous versions. Because of this, Vista also ships with Direct3D 9 to support the thousands of applications and supporting hardware in the new operating system. There is also a revised version of D3D9 that is capable of utilizing new features provided by WDDM, called D3D9Ex, which is used by several Vista-specific applications such as the three-dimensional desktop.

» DX9 VERSUS DX10

While Direct3D 9 represents over a decade of development, it is not without its flaws. Below are a few of the problems faced in D3D9 and how D3D10 will address them:

• API Object Overhead
Before your graphics card renders a frame, it must wait for the application to tell the D3D API what needs to be rendered, which then tells the display driver how to render it. The CPU handles all of the communication between the four entities, which, when done many times per second, uses up a lot of resources that could otherwise be used for physics or artificial intelligence. The amount of this overhead is such that the number of objects rendered in any one frame must be limited to prevent a massive CPU bottleneck. Designers must carefully balance every visual aspect of a game so that it can run smoothly.

Solution: The Direct3D API was completely rewritten to reduce object overhead by nearly ten times, allowing developers to put much more into games. The only limitation is the hardware's performance capability. (Figure 1)

• Fixed Pipeline Shader Architecture
Previous GPUs were designed with reservations as to what type of processing can be done in particular pipelines, such as vertex or pixel shading (the method through which visual effects are applied to vertices and individual pixels in a frame). If the pipelines were lanes in a highway, these reservations would dictate which lanes can be used by trucks and which can be used by cars. Depending on the traffic, there may be five times as many trucks as cars, resulting in the congestion of some lanes and the relative emptiness of others. The same holds true for shading pipelines; if a scene required much more vertex than pixel shading, work that the pixel pipelines could be doing is wasted and vice versa.

Solution: DirectX 10 is based upon a unified shader architecture. Instead of assigning a specific number of pipelines for each task, several multi-purpose pipelines are available for any type of shading that needs to be done. This results in overall faster processing. (Figure 2)

• Capability Bits
Thus far, graphics card manufacturers have had a bit of wiggle room when designing their DirectX 9 processors. There are several optional features, called capability bits, which may or may not be supported by each GPU and do not affect their qualification as "DX9 capable." The discrepancy in supported features caused problems for game developers, who had to spend more time programming to make sure each method used by different GPUs would produce the desired result in-game.

Solution: There is a strict, standardized set of specifications that a GPU must meet in order to be called "DX10 capable." The developer need not worry about which GPU the user has, only that it is qualified for DX10.

» ROLLING OUT DIRECTX 10

Obviously, newfangled graphics software is worthless without the hardware to implement it. NVIDIA was first into the fray with their GeForce 8800 GTX. With 128 unified shaders, 768MB of GDDR3 VRAM, and the G80 core running at 1.35GHz, 900MHz, and 575MHz, respectively, it's a force to be reckoned with. However, prices range anywhere from $550 to $800, depending on manufacturer-specific overclocking and cooling options. Fortunately for those on a budget, you can get an 8800 GTS for around $300 or wait a month or two for the 8600 and 8500 series cards. Prices on the latter two are yet unconfirmed, but DX10 capabilities for under $200 may not be out of the question. Just expect the performance to be fairly proportional to the price.

ATI/AMD's DX10 offering, codenamed the R600, will feature their second attempt at a unified shader architecture; the first was the Xenos chip created for the Xbox 360. Officially released specifications for the Radeon 2900XTX include 700 million transistors, 1GB of GDDR4 VRAM with a 512-bit bus, a board length of 9.5" (12" for OEM), dual-slot vapor chamber cooling, and native HDMI and Crossfire support. However, it has been repeatedly delayed and is now headed for release in the second quarter of 2007. While doing so allows AMD more time to refine their product based on consumer expectations, they risk losing market share to their competitor. On the bright side, this provides more time to scrounge up the rumored $600+.

Since the GeForce 8x00 cards hit retail a few months ago, the lucky few that could afford it have been wondering when they will get to flex its DX10 muscle. Well, a variety of games are being developed specifically with DirectX 10 in mind, including Crysis, BioShock, Alan Wake, Unreal Tournament 3, Hellgate: London, Age of Conan, and World In Conflict. There are also plans for patches that will enable DX10 support in titles already released, such as Flight Simulator X, Company of Heroes, Supreme Commander, and EVE Online.

» DID SOMEONE SAY CRYSIS?

If you have not heard of Crysis, I would like to welcome you back from whatever desert island you've been living on for the past couple of years. Hands down the most gorgeous video game anyone has ever seen (see Figure 3), it is at the top of many a must-have list. A veritable poster child for gaming on Windows Vista, much of the jaw-dropping visuals are achieved using the advancements brought about by DirectX 10. While it is true that DX9 is technically able to produce similar effects, the limitations discussed earlier would prove it to create little more than a pretty slide show.

DX10 is about immersion, for us. DX9 is about giving fidelity and graphics quality as much as we can, but DX10 is about video-realism. It's about the motion, the blurs, the depth of field, the cinematic effects like volumetric lighting, atmospheric scattering... All of that which you would see in photos, to get realism into the gaming. That's about DX10, getting cinematic gaming, essentially, into Crysis. - Cevat Yerli, CEO, Crytek

Cinematic effects like motion blurring and depth of field more realistically mimic the way the eye works. In Figure 4, you can see the blurring effects on the falling tree, the alien machine's tentacle-like arm, and the Korean soldier attempting to dodge said tentacle-arm. A camera recording at 25 fps is collecting image data over an interval of 40 milliseconds. Any motion that happens throughout that interval is combined into a single frame, causing a blur in the image. A similar effect occurs while your eye is accumulating visual data over a period of about 125 milliseconds. Figure 5 shows an an example of depth of field. The camera is focused on the chair in which the nano-suit clad soldier is sitting, while everything beyond is, well, out of focus. It's a fairly new concept to video games and may seem strange at first, but it is a perfectly normal and accepted optical phenomenon.

It's getting close to photo-realism, and that's the key, basically. When you get there, it's something that is exciting, and you can't be more real than real-looking... It runs great on DX9. DX10 brings much more fidelity and many more particles and a smoother experience. So basically, it's on top of an already great experience on DX9. - Jack Mamais, Lead Designer, Crytek

You could stare at screenshots all day (see Figures 6-8), but the real beauty of Crysis comes out in motion. Do yourself a favor and watch any of the numerous videos that have come out in the past few months. I particularly recommend one from the recent Game Developer's Conference that shows off the level editor and the dynamic day/night cycle. Suffice to say, you will be amazed. Crytek is tight-lipped concerning a release date, saying it'll come out when they're finished with it. They have, however, announced plans for a multiplayer beta sometime soon, so keep your eyes peeled.

» DX10, WINDOWS VISTA, AND YOU

PC gaming is not a cheap hobby. It never has been and it never will be. There is no doubt that keeping up with the Joneses is much more expensive than buying a new console every four years. The trade-off is that you can always be ahead of the curve, and that's part of the fun!

Due to the lack of WDDM, it is extremely unlikely that Windows XP will ever see any form of DirectX 10. Like it or not, if you want to have the best possible experience with the newest games, you need Windows Vista. This is quite a bone of contention for those of you resisting the switch.

The most common reason not to upgrade seems to be how Vista requires more resources than XP. I am baffled by the people that expect their rig to run a brand new operating system as well as it ran a five-year-old one. The natural progression of software has intimate ties with the explosive growth of hardware. There is so much computing power available to the consumer, at all price points, but when an application wants to make use of it, it's labeled a "resource hog."

There are plenty of reasons not to switch to Vista. For basic tasks - email, web surfing, movies or music - you'll be fine with XP. Many businesses have deemed Vista unnecessary for their needs. That's fine, too. But for gamers, I firmly believe the answer is quite clear. You need Vista and what it will bring to PC gaming.

Whether or not requiring an operating system upgrade in addition to a new multi-hundred dollar graphics card is too much... that's subjective. Do you wait until XP and DX9 are forgotten and you are forced to upgrade, kicking and screaming? Or do you bite the bullet, upgrade your machine, and revel in the glory that is the bleeding edge of gaming goodness?

I say, if you can't stand the heat, get out of the kitchen.