Volume: 29 Issue: 1 (January 2006)
Let the Games Begin, Part 1
|One of the most popular gifts this past holiday season was Microsoft’s Xbox 360. For those lucky enough to have unwrapped one, there is little question as to why this relatively small gift box was on so many wish lists. The first of the new gaming consoles to be released by the big-three vendors, the machine was met with great fanfare as hopeful buyers flocked to stores for their chance to experience the next big thing in computerized gaming.
As Sony and Nintendo prepare their systems for release later in the year, Microsoft alone ushered in the next generation of interactive entertainment, which offers the power and performance that players could only have dreamt about a year ago.
Taking an early lead in the billion-dollar gaming industry, the Xbox 360 is giving players a good look at the present state of gaming, where graphics are on the fast track. In Part 1 of this series, we take a peek under the hood of the console, to see what’s driving the next-gen titles. Next month, in Part 2, we examine the new Xbox 360 title Project Gotham Racing 3, to see how far one developer pushed the console’s capabilities.
Microsoft’s Xbox powers next-gen gaming
On November 22, 2005, the look of computerized gaming in North America changed radically. That’s when Microsoft released its Xbox 360, the first in a trio of expected new consoles to hit the market within the next several months. (Because Microsoft came late to the console game, the 360 marks the company’s second hardware release, while competitors Sony and Nintendo are preparing their third systems.)
Far more than a game console, the Xbox 360 is a video game and digital entertainment system that, in addition to fueling high-def gaming, lets users port music to the hard drive, watch progressive-scan DVD movies “right out of the box,” and instantly stream and store digital video and other media, including digital photos.
Unveiled on MTV in May 2005, the Xbox 360 is touted as placing the user at the center of the experience, anytime, anywhere. The machine is always connected (through its Xbox Live feature that allows a person to play with others in any location), always personalized (with a customizable interface), and always plays in high def (at 720p or 1080i resolution).
The machine-by taking advantage of the industry’s latest breakthroughs-represents a dramatic leap forward in high-def gaming and entertainment (see the table, below). As a result, gaming experiences are more expansive, dramatic, and lifelike than ever before: Epic worlds spring to life with unprecedented detail, while extremely intelligent characters display a depth of emotion never before associated with gaming. Realism emerges not only in the advanced texturing and lighting effects of the graphics, but also in the way the settings themselves respond to characters’ movements. For instance, if an enemy hiding in brush makes a sudden move, the player will hear and see leaves rustle, alerting them to the character’s presence.
The first of the new game consoles to hit the market, Microsoft’s Xbox 360 incorporates state-of-the-art hardware for a dramatic leap forward in high-def gameplay and game graphics.
According to Chris Satchell, general manager of the Xbox Game Developers Group, the 360 provides a true generational leap in every aspect of the system’s hardware, software, and services for advancing gameplay graphics. For example, the cutting-edge custom GPU offers innovations such as 48 parallel-processing ALUs, Shader Model 3.0+, and real-time automatic scheduling of system resources, allowing every game to run at either 720p or 1080i resolution.
Microsoft has paired the GPU with a custom CPU running at 3.2 ghz and featuring three symmetric cores. The CPU offers huge processing power for large-scale, complex worlds. To provide storage for this level of detail, the vendor has added 512
mb of ultra-fast system RAM, a 12X DVD drive, and a 20
gb removable hard drive. “When added together, these elements allow visual and gameplay experiences beyond anything seen in the current generation,” proclaims Satchell.
Compared to the first generation of the Xbox, the 360’s GPU is capable of processing almost 30 times more shader instructions (in the thousands of instructions) and 40 times the fill-rate bandwidth. Moreover, the Xbox 360 has double the bandwidth and has eight times the memory of the Xbox 1, allowing developers to simulate massively rich worlds. Aside from providing a new level of graphics fidelity, these functions are now able to process the kind of effects in real time that previously had to be prerendered. In addition, the CPU has 10 times the processing power of the Xbox 1 and offers a blend of general-purpose processing power for game logic and math horsepower to drive next-generation physics, animation, and AI.
“The key to the system is in the balance of each element,” says Satchell. “For example, the GPU has 10mb of embedded DRAM connected to the core, with a 256
gb/sec dedicated bus, to ensure that the system never gets fill-rate bound while rendering large, complex scenes-a common problem with current-generation graphics processors.”
Also unique to the Xbox 360 GPU is automatic load balancing of the 48 parallel ALU processing units. This means that for every cycle, the GPU automatically adjusts to the different rendering demands, thereby allowing the system to utilize its power more effectively than with a standard architecture.
According to Satchell, it is impossible to predict how game developers will begin to harness this power, although there are some common features that are likely to be exploited in new game releases. For instance, the vertex- and pixel-processing power will let many off-line techniques (such as displacement mapping, normal mapping, dynamic ambient occlusion, and global illumination approximations) run smoothly in real time.
“As developers start to take advantage of the hardware tesselator, gamers will see smooth, lifelike characters,” says Satchell. “The multi-core symmetric CPU has custom math-processing capabilities that allow complicated, dynamic simulations and complex artificial intelligence to be infused with new levels of animation, resulting in stunning, movie-like scenes containing many participants. And, characters will feature detailed secondary animations and have dynamics simulations for ultra-realistic actions and reactions.”
With the 360, gamers will experience a huge increase in texture detail from the use of high-resolution textures and deeper multi-layer techniques. (Novel texturing techniques, such as normal and displacement mapping, are becoming commonplace due to the newfound bandwidth, system memory, and GPU processing power.) Additionally, models are becoming much higher in resolution, and as developers become more familiar with the console, Satchell expects to begin seeing higher-order surfaces, this due to the inclusion of the hardware geometry tesselator within the GPU.
Additionally, scenes will be filled with hundreds or even thousands of characters. Because developers no longer will have to trade visuals for gameplay, complex games now will be more immersive, notes Satchell, and the use of new online services, such as the 360’s massive spectator mode (for watching friends’ gameplay), will offer new ways for the user to interact with the game world and the gamer community.
So, how will the level of detail in the Xbox 360 games compare to what we see presently in feature films or broadcast? Satchell expects a transition period while game developers mine the rich hardware resources of the new system. However, soon thereafter, he believes the techniques that previously were employed only for high-end film rendering will become common within the real-time realm. Also, the increased number, complexity, and texture resolution of in-game characters will start to close the gap between games and prerendered content.
For instance, polygon counts will increase dramatically, resulting in central characters comprising up to a quarter of a million polys. “When you add advanced lighting and shading techniques, like sub-surface scattering, displacement mapping, and ambient occlusion, you approach a look that is far more like film than we have ever seen before in games,” says Satchell.
Moreover, because every Xbox 360 game title will be playable in high definition, the real-time imagery will take a visual leap beyond current prerendered standard-definition visuals, such as those currently prevalent on television.
Perhaps most impressive is the fact that all this imagery fits inside a book-size box, which uses advanced compression techniques to maximize the available memory for both visual and audio resources. Remarkably, with the sheer amount of CPU and GPU processing power, it is now more viable to calculate required data than to store it in a pre-computed format. And, with multi-core architectures, developers can utilize real-time streaming of data from a DVD or hard drive without slowing gameplay.
“The stored data can also be kept in compressed formats to make better use of the storage capacity and streaming bandwidth,” Satchell says. “The overall effect of these features means that developers are able to store far richer game worlds and render them in true high definition.”
And with this, a visual revolution has begun.
Karen Moltenbrey is the executive editor at
Computer Graphics World.
To illustrate the potential of next-gen games-particularly those powered by ATI’s Radeon graphics technology-the video-card maker joined forces with digital studio Rhinofx to create “The Assassin,” the third installment in the duo’s series of cinematic Webisodes geared for the video-game environment.
The latest episode was featured this past summer at the E3 game conference and at SIGGRAPH, both times running on the new Xbox 360 console, which sports a customized ATI graphics processor. The cinematics in “The Assassin” operated solely off ATI’s GPU in order to accurately demonstrate its capabilities within an interactive environment. According to Bob Feldstein, vice president of engineering at ATI, viewers can turn various effects (such as shaders) on and off within the demo for a visual look at the card’s latest functionality.
“The demo provides a vision of what game developers can do with the shaders and other features of the GPU-produce hair that blows in the wind, detailed skin textures, and realistic motion,” says Feldstein.
A year and a half ago, ATI and Rhinofx produced “Doublecross,” a technical demonstration that was soon followed by “Dangerous Curves,” used to illustrate the power of ATI’s X800 and X850 cards, respectively. All three episodes feature ATI’s Ruby character, a lean, mean, alluring secret agent who doubles as a global-branding icon. “Now that Ruby is recognizable, we’re able to push the envelope in terms of who she is,” says Rhinofx director Harry Dorrington, who spearheaded Ruby’s design and development. So, who is Ruby in this new adventure? She is a heroine with vulnerabilities and a warrior who can appreciate the threat posed by a formidable enemy, he explains. In “The Assassin,” that enemy is the title character: a new Dorrington creation named Cyn, a cold, snide, aggressor.
Cyn exists not only to take on Ruby, but also to take the ATI technology to another (game) level. A number of advances combine to deliver heightened realism in the characterizations, artistically elevated lighting schemes that underscore the dramatic element, and greater overall detail-all rendered in real time and without slowing gameplay, says Callan McInally, manager of ATI’s 3D Application Research Group.
With the Xbox 360, the team was able to push the look of “The Assassin” beyond what it had accomplished in the first two installments in terms of technology and aesthetics, says Dorrington. For instance, the characters’ skin textures are more physically accurate as a result of subsurface scattering, a process not typically found in gaming.
“The proof is in the polygons,” Dorrington says, “the more polys you have to work with, the more realistic the imagery becomes.” To this end, “The Assassin” has 25 percent more polygons than the previous segments. While Ruby is essentially the same model (80,000 polygons) from the previous episodes, the new hardware enabled the group to expand the environment and other characters-Cyn, for instance, consists of more than 120,000 polys-all of which use complex lighting calculations for added realism. As Feldstein points out, in the past, more polys would have meant a slower gaming experience; but with the latest graphics hardware, that was not an obstacle.
The differences in the animation are more difficult to identify, but they are present. Using Alias’s Maya, Rhinofx animator Dan Vislosky modeled and rigged the characters with a setup that allowed the group more freedom when editing the corresponding mocap data and blending between the mocapped and the keyframed animations. Also new to the series is an HDRI lighting setup, which communicates more information and delivers more accurate renderings.
On a creative level, the success of the first two Ruby installments has paved the way for narrative development. Now that there is a structure to the brand, the teams are adding twists to the story line, such as killing off Ruby’s nemesis, Optico, in the beginning of “The Assassin” and orchestrating a fight to the death between Ruby and Cyn. As such, Dorrington approached this project as he would a movie. “There is an implied depth to the series, and we’ve always treated it like a film trailer, or a snapshot of a larger picture,” Dorrington says. “We’ve got enough story lines collected so that if we wanted to do a feature film, we could.”
According to Dorrington, one reason why Ruby works so well, particularly in the gaming market, is that the audience is both critical and knowledgeable, absorbing the layers of the character as well as the technical capabilities of the gaming system. “The audience is so informed that it needs to see things in a more realistic and tangible way,” he says.
As McInally points out, at every gaming trade show, the number one question posed to the group is, when is the game coming out? “That tells me we have hit our mark,” he says. Alas, no Ruby game is on the horizon, but expect to see the heroine continue her adventures in a future technology demo.
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