Could a zombie really teach your development team how to optimize its game software? The answer is yes if the zombie is Zombie Studios, the Seattle-based creator of the popular Blacklight*: Tango Down multiplayer shooter game for the PC, Sony PlayStation* 3, and Microsoft Xbox* 360.
With a background that includes building simulation systems for the U.S. Department of Defense, Zombie founders Joanna Alexander and Mark Long are no strangers to virtual reality. Their young company is currently hard at work building Blacklight: Retribution, the sequel to Tango, that unlike its US D 15 predecessor will embrace a free-to-play model that relies on ingame microtransactions for revenue and will be available only for the PC.
Zombie’s lead developer Chance Lyon is charged with squeezing every possible drop of performance from Retribution while supporting the largest spectrum of PC configurations possible. Considering the enormous variety of PC, processor, memory, and GPU combinations, he’s got his work cut out for him.
To ease the job, for the past eight months Lyon has been using Intel® Graphics Performance Analyzers (Intel® GPA), a free optimization suite that comprises platform, frame, and system analysis tools for Microsoft Windows* applications. “We rely on Intel GPA to help us decide where to make platform-specific trade-offs,” said Lyon.
To hear Lyon tell it, Intel GPA can be set up and working in minutes on his team’s development workstations, which happen to be equipped with the 2nd generation Intel® Core™ i7 processor, 8 GB of memory, discrete GPUs from either ATI or NVIDIA, and two or three monitors each. Once Intel GPA is configured to auto-detect launched applications, it picks up Zombie’s games automatically “ . . . and capturing frames is very easy from there,” said Lyon.
We’ve found [Intel® GPA] integrates easily with basically any engine, offers lots of flexibility, and most important, it’s stable and being actively maintained, which makes me very happy.”
—Chance Lyon, Lead Developer, Zombie Studios
Lyon has come to rely on Intel GPA to identify potential performance problems early in the development process, where they can be remedied most quickly and with the least expense. When testers report a big drop in frame rates, for example, Intel GPA Frame Analyzer quickly identifies the components within the frame causing the bottleneck.
Plenty can also be done at runtime to optimize application performance. “With DirectX* 11, we can exploit quite a bit of scalability using dynamic tessellation, image reflection, and other features. Based on runtime detection of players’ system characteristics, we can turn these on and off.” At the very low end, for example, levels of shader complexity can be reduced, objects can be removed, or detail can be lessened. “We can certainly reduce data rates to the client if necessary.”
The stability of Intel GPA tools also has proven to be a key benefit to Zombie. Prior to Intel GPA, Lyon and his team used “ . . . a combination of Unreal Engine* 3 in-game metrics for CPU profiling and [Microsoft’s] PIX* when debugging GPU issues. “I have also used RAD Telemetry* and NVIDIA PerfHU D* on the PC, as well as a slew of console-specific profiling tools.”
Building an Audience
Lyon and his team strive to create optimal play experiences for individual gamers, which they see as one of the best opportunities to grow the Blacklight: Retribution following. Lyon investigates optimization opportunities by digging into the data he gets from the Intel GPA tools.
The heads-up display, a major advance introduced with Intel GPA 4.0, superimposes performance stats atop a running game. This is particularly useful for delivering productivity when hunting for the cause of bottlenecks. “Having timely, accurate, easily accessible data is key when I’m trying to optimize play experience across the continuum of platforms we span,” he said. “Ultimately, the results of optimizations using the Intel GPA tools make the game experience better and better for players. [And] the faster we can make the game, the more features we can include.”
Lyon relies on the productivity and performance advantages that leading-edge Intel® processors and solid-state drives afford his team. In addition to systems built around 2nd gen Intel Core i7 processors, Lyon’s six-member engineering team recently added Intel® Solid-State Drives and has seen a marked performance improvement in their development workstations. “My team has some pretty lofty hardware requirements,” said Lyon. “Every day, they are compiling, running, and debugging code, and working to evaluate the effects of various artwork approaches. Every little bit of added performance helps.”
Of course, the programmers also take advantage of multi-threading. “We’re using a lot of the SIM D (single instruction, multiple data) instruction sets for the animation systems in the game, particularly for skeletal animations,” said Lyon. (For an in-depth look at using SIM D programming techniques to improve application performance, read “Optimizing Applications Using SIM D Applications” at software.Intel.com/file/33940/). “It’s very demanding work, so I do everything I can to keep them fully productive.” The team’s 2nd gen Intel Core i7 processor systems have proven themselves more than capable of keeping Zombie developers productive through the company’s aggressive development cycles.
The Science of Optimization
Lyon suffers no illusions about Zombie Studios, which he sees as a small fish in a big, crowded pond. “We have to go head-to-head against other game publishers that have hundred-million dollar marketing budgets and years of release cycles on us.” So to get noticed, Lyon said Zombie’s games “will have to be remarkable.”
To accomplish this, Lyon said Zombie’s strategies have been to focus entirely on making games that are fun to play and to make optimization decisions based on hard performance data (not hunches). To provide the necessary insight, he has integrated Intel GPA Platform Analyzer within Zombie’s in-game stat system, a process that he described as “relatively painless.”
“This has allowed me to dig into the call stacks to do CPU profiling traces.” Armed with this information, Lyon can easily pinpoint major performance problems that might otherwise have remained hidden. For example, he can now study patterns of line trace calls, which can account for as much as 30 percent of frame time on the server side of the game. “Reducing those or offloading them to other threads is a considerable challenge, but it can be accomplished given enough data to fully define impacts on gameplay,” he said.
Intel GPA for Collaboration and Workflow
For a game on the scale of Blacklight: Retribution, optimization is never just about code. The structure, content, and interactions of artistic elements can matter as much or more than engineering approaches when it comes to performance. Resolving art-related performance bottlenecks often demands that two very different groups of people—artists and software developers—work together, communicate effectively, and learn from mutual experience.
Lyon described how he uses Intel GPA Frame Analyzer to identify bottlenecks and help engineers and artists collaborate more effectively. During a recent test play, Lyon noticed extremely sluggish performance from the program’s main menu. “[It] was rendering only about 10,000 polys . . . at 15 frames a second,” said Lyon. Nobody could figure out why performance was slowing to a crawl when there was just a single character on the screen and an apparently simple background menu.
Lyon used Intel GPA Frame Analyzer to dig into exactly what was taking up all of the rendering time. “It turned out that the background menu was extremely complex and included several layers of full screen blur.” Armed with this knowledge, he asked Zombie’s UI team to refactor that entire background menu. “The frame rate went from 15 to a solid 60 immediately.”
In another case, they discovered that the terrain in an entire level was being rendered in a single draw call, regardless of where the character was positioned. “With [DirectX] 11 tessellation, this meant we were drawing 300,000 triangles. We got the artist to divide the terrain and draw smaller increments less frequently.”
Without the Intel GPA Frame Analyzer data, Lyon said it would have been difficult to explain to the UI developers what they need to do differently. “Sometimes we have to ask the artists to do things in ways that are counterintuitive to their aesthetic mindset. It really helps to have rendering statistics in hand, so I can explain without seeming arbitrary. We’ve had a lot of success finding problem assets using the Frame Analyzer.”
Professional Advice on Professional Tools
With only six engineers, Lyon and his Zombie team have to wring every bit of productivity out of every day in their development schedule. For doing so, Intel GPA tools and hardware technologies have proven to be key assets. “We start with an accurate, detailed Intel GPA profiling of the engine,” he said, adding that without such concrete knowledge about what’s actually going on in the program, the team is running blind and guessing. “That wastes time and money and makes it harder to get to a stable game.”
For Zombie, Intel GPA has been a key tool for optimizing GPU and CPU performance. “We’ve found it integrates easily with basically any engine, offers lots of flexibility to use it the way we want, and most important, it’s stable and being actively maintained, which makes me very happy.”
Unearthing Zombie Studios
Finding two people more qualified than Zombie Studios founders Joanna Alexander and Mark Long to run a game development company would be a challenge indeed.
Co-CEO and COO Alexander has a BS in Mathematics from Yale and a Masters in Engineering from Princeton. She has led virtual-reality research in the Simulated Systems group at the Sarnoff Research Center where she received the lab’s Technical Achievement Award, has conducted research at the Max Planck Institute for Nuclear Physics in Germany, and served as Deputy Chair of a U.S. Department of Defense committee formed to advise government and military officials on issues relating to technology transfer and virtual reality.
Co-CEO , and designer and producer Long has an equally impressive background. He has produced more than 28 titles, and as a former member of the Silicon Graphics, Inc. advisory board advised SGI on requirements for their next-generation virtual-reality systems. His research experience spans the Sarnoff Research Center, University of Texas Institute for Advanced Technology, and General Dynamics’ Combined Arms Systems Engineering Laboratory. He has collaborated with the National Science Foundation, the University of Washington Human Interface Laboratory, and the University of Illinois to produce a summary report for the Congressional Task Force on Virtual Reality. He also co-chaired, with NASA and the Stanford Research Institute, a conference on next-generation virtual-reality research.
Tapping the intense military symmetry, Blacklight: Retribution could be the company’s most heart-poundingly authentic game yet. Alexander and Long formed Zombie Studios in 1994 with an eye to developing virtual-reality technologies for commercial and military uses. Today, while Zombie Studios mostly focuses on the consumer-gaming niche, the company’s Serious Games Division is still active in creating live-fire military simulations where real shooters train using real weapons and real bullets in virtual environments.
With Blacklight: Retribution, Zombie enters a new area of the gaming business: The free-to-play model, under which revenue is generated when players purchase game-related items such as ammunition, supplies, or clothing. “Future game-revenue streams will shift from up-front purchase to in-game microtransactions,” said Lyon. To succeed in this new business environment, a game must be feature-rich, immersive, and above all, engaging. It also has to perform well across a variety of platforms. In the free-to-play model, first impressions are critical because games must both attract players and retain their interest. “To win customers, we’ll have to compete for their time and attention before we get to compete for their money,” said Lyon. “Free-to-play is the future of multiplayer online gaming.”
With Zombie’s involvement in live-fire military simulations, let’s just hope they don’t invent a way to make those virtual realities cross over into the physical world.
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