Watch a movie on a Blu-Ray disc. If you know where to look — and what to look at — you’ll see something strange. The images aren’t crisper than those you’ll find in video games. Quite the opposite: distant objects can seem fuzzy. In games, by contrast, they’re often sharp and jaggy. That’s part of why movies can seem more lifelike and immersive.
It takes an artist’s eye to notice details like this. And it takes a hard-core coder to do something about it. Tim Lottes is both. Maybe that’s why the NVIDIA engineer’s technology has been built into hundreds of games. Lottes specializes in a field of visual computing known as ‘anti-aliasing.’ The aim is to smooth the jagged lines created when putting an image on a screen composed of dots, known as pixels.
His latest creation is an anti-aliasing technology dubbed TXAA (temporal approximate anti-aliasing). The NVIDIA-only techology, which debuted in July, gives games running NVIDIA’s latest Kepler-based GPUs a more cinematic feel. In the five months since its debut, TXAA has been built into “The Secret World,” “Assassin’s Creed III,” and “Call of Duty: Black Ops II.”
It helps that Lottes knows how to think like a game developer. Before joining NVIDIA, he worked at computer game developer Human Head Studios.
For years, the way graphics were generated for movies and videogames were different, he says. Now, developers are looking for technologies that mimic the look of a Blu-Ray movie. “My personal goal is to get games up the quality of a feature film,” Lottes says.
That’s a goal propelled forward by the 34-year-old’s passion for landscape photography. You begin to notice small details when stitching together realistic panoramas out of high-resolution images, he says.
Lottes also has a knack for writing ‘low-level’ code. He likes stuff that’s as close to the bare metal in a machine as you can get. “I was writing assembly language before I was a teenager,” says Lottes, who holds a degree in Computer Science from the University of Illinois, Urbana-Champaign.
So when he got the chance to join NVIDIA three years ago, he jumped. He soon began working on an anti-aliasing technology now known as FXAA (Fast Approximate Anti-Aliasing). Inspired by a technique that ran slowly on CPUs, known as ‘MLAA,’ Lottes aimed to come up with the fastest possible anti-aliasing technique for GPUs.
Rather than using hardware ‘multi-sample anti-aliasing’ (MSAA) — a process that takes place as an image is rendered — FXAA smooths the edges on the screen after all the rendering is finished. The result: more life-like images on older, slower hardware. The technology is now used in many of the top tier video games for the PC, PlayStation 3, and XBox 360.
Lottes wasn’t satisfied, however. His latest creation, TXAA aims to remove the crawl seen on the edges of objects and inside many shaded surfaces that appear as characters move through a virtual world. “I wanted to take what the film guys have been doing with anti-aliasing and get as close as I could to that,” Lottes says.
Not easy, considering filmmakers can rely on banks of servers working days, or weeks, to generate life-like effects. To do that Lottes exploits his knowledge of NVIDIA’s GPUs to craft a compact ball of code that can deliver superior image quality with a smaller performance impact. The trick? “I do the right amount of work, and I don’t do too much work,” says Lottes, who is already working on another round of improvements to TXAA .