When Sony announced the PlayStation 5 in early October, system architect Mark Cerny went out of his way to clarify that “ray tracing” will be baked into the hardware. He believed it was “the statement people were looking for.

More than just a buzzword, gamers understand the term as the clearest signal of “next generation graphics,” despite the technology being conceived in 1969. For years, it’s been a feature of big-budget Hollywood films (see this white paper Pixar wrote on ray tracing in “Cars”). It has not made its way into the gaming world en masse until now, however.

In simplest terms, ray tracing is a computer’s graphical simulation of how light works in the real world. Complex algorithms would re-create how a beam of light would act, creating color that bounces and reflects off other objects, creating more realistic shadows and reflections.

Until recently, games have struggled to communicate its appeal. And more importantly, it’s tough to implement in games because it requires so much processing power. Movie studios like Pixar can run wild with effects when there is a set sequence of events, but game developers have to make sure their game is a playable, smooth experience that can render graphics based upon the player’s inputs rather than a static script.

Enter Remedy Games’ Control. The game is ray tracing’s “killer app,” as dubbed in the above video by Digital Foundry, a games technology analysis shop.

Alex Battaglia is a Digital Foundry analyst who initially freelanced for the shop for two years as its resident PC graphics expert. He’s made 10 videos explaining ray tracing to an audience of gamers already fluent in graphics technology. But it wasn’t until he covered Control when it clicked for his viewers.

“It was too abstract,” Battaglia said to The Washington Post. “If I just described the physics of it, I don’t think people can picture it in their head and how it applies to the game. But with Control, there was this moment when you see your character’s reflection in a bottle, or a weird redness bouncing light from a chair ... that’s when it clicks."

The comments under the video reflect the sentiment, saying Battaglia’s explanation of modern graphical features were even better than the explainer by Nvidia, the company creating expensive graphics cards enabled with ray-tracing features.

Battaglia made a detailed analysis of Control’s ray-tracing tech on the Foundry’s YouTube channel, but also provided the following high-resolution comparison images he used to The Post.

You can easily see the difference in this bottle, particularly the amount of depth given to the image thanks to the prominent reflection of the room, the material of the wall, and the deeper blacks on shadows.

Control, a psychological thriller, takes place in the Brutalist architecture of a federal agency, with plenty of sterile but clean surfaces for the technology to shine.

“Given the game’s wealth of shiny surfaces, opaque reflections and transparency reflections on average are going to be the largest differences you’ll ever see,” Battaglia said.

Notice how the red frame around the shelter service hatch renders more accurately — a slightly different shade because of the light reflecting at a different angle than the flat hatch — with ray tracing effects turned on, not to mention all the off-screen objects like the red carpeting (behind the main character) being reflected onto the wall (at about shoulder level).

PC games often have dozens of options for players to tweak visual settings to meet their computer’s specs. Battaglia would often use special tools to explain the ray-tracing concept. Control was the first game where the difference was stark enough for anyone to notice.

“It was one of the first times where I could explain what was happening graphically in the game just by using the game itself,” Battaglia said. “All I had to do is load up the game, and turn settings on and off to get the point across.”

The below image shows objects and light sources not visible on screen appearing clearly in the sheen of this pool of blood.

With ray tracing, lighting and reflections feel more dynamic. Reflections in games are usually pre-rendered static images, called “cubemaps.” But look at the ketchup and mustard bottles, and how the light bounces off them to have their red and yellow colors reflect off the coffee carafe.

With ray-tracing reflections and shadowing, the staircase behind playable character Jesse Faden is reflected along the sheen of the wall. Shadows are cast more accurately on Jesse’s jacket, as well as her hair. Note the shadowing between Jesse’s leather jacket and her shirt, giving the character model a more realistic impression of depth and layers.

And details along this wall are lost without ray tracing. With ray tracing, objects that appeared dark finally have light against them, revealing the world reflecting off the wall’s surface.

At this point, no one outside Sony knows what ray tracing on the PlayStation 5 would look like. Digital Foundry prognosticated the PlayStation 5′s guts based on the WIRED magazine article. Based on patents filed by AMD, which is working with Sony to build the next console, Foundry analysts guess that the next Xbox and PlayStation machines may still not have ray tracing as complex as the current Nvidia graphics cards, including what’s on display with Control. But consoles also come with custom configurations, so its capabilities are still unknown.

EA’s Battlefield V, released late last year, is actually the first game to feature ray-traced reflections. But Control features five ray-tracing options including reflections, debris and transparent reflections.

“The way they implemented ray tracing, they slotted it in and modified existing effects,” Battaglia said. “You get a prettier-looking version of the game, and their way of designing it is actually the smartest way to go about it. We’re in the nascent days of what it looks like now.”

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