What is ray tracing? (and what it means for computer games)

Have you noticed your eyes dilate a lot when you’re playing lately? If so, it could be because new technology is slowly spreading across the game field. The latest and greatest visual improvements in PC gaming are delivered through ray tracing, something only recently made possible in real time using specialized hardware.

Although ray tracing is commonly referred to in PC games, Microsoft’s Xbox Series X and Sony PlayStation 5 also have the necessary hardware and a growing library of games that support it. This article discusses how ray tracing differs from traditional rasterization, why it’s important to the future of gaming, and of course, whether ray tracing should impact your next gaming PC purchase (whether it’s a gaming desktop or gaming laptop) or console.


Ray tracing basics

Ray tracing is a well-functioning technique for illuminating a computer-generated scene. The concept is not new; what or what He is What’s new is access to computational muscles to pull them efficiently.

Imagine shooting a beam of light at an object and tracking how it bounces off the surface, almost like walking into a dark room and pointing a flashlight. Then imagine shooting several rays, using the ones that come back (and don’t come back) to find out what the scene should look like. For example, rays that fail to return are likely to have been blocked by an object, thus creating a shadow. (Thinking of the concept in the same way that radar does is not far off.)

Basic diagram of how ray tracing works

This basic explanation shows how ray tracing parallels real-world illumination: the light that reaches your eye tells your brain what you see. Animation films have been using ray tracing for decades; Pixar Toy Storyfor example, came into the limelight in 1995, and great strides have been made in its introduction since then.

For as long as the movie industry has been using ray tracing, video games have relied on a different technology, rasterization, to render 3D worlds. But, before we get into the reasons behind this, let’s contrast ray tracing with drip.


The basics: ray tracing vs. rasterization

Rasterizing is an object-based approach to rendering a scene. Each object is drawn in color first, then logic is applied to show only the pixels closest to the eye. By contrast, ray tracing colors the pixels first, and then identifies them with objects later. Simple… That explains it all, right?

NVIDIA GeForce RTX 3080

Nvidia GeForce RTX 3080 is a high-end graphics card with hardware ray tracing support.

so no so farSo think of it this way. The rasterization process requires special techniques, adjustment and alteration to create realistic images. For example, a game view pipeline may be designed and optimized to apply a specific effect, where pixels on an object have a certain style. Naturally, this kind of reasoning varies from object to object and from scene to scene. It takes effort on the developer’s part to take advantage of this, but it can pay off efficiently, as a computer may be able to render a complex scene without proportionate amounts of processing power.

Ray tracing tends to be applied in a more general manner than rasterization, as it is based on the imaging of light rays. As a result, the techniques for achieving visible results using it depend on how these rays are used. Softer shadows and reflections, for example, require more rays to be fired, while motion and opacity effects may require changing the ray timing or ray point of origin.

In general, rasterization and ray tracing can be used to achieve the same result (or at least come close to it). Now let’s explore why one is used over the other.


Mainstream games, meet ray tracking

Decades ago, dashing took its place in video games because the hardware required to do so was affordable enough for regular buyers to access, as opposed to what was required for ray tracing. This is still very much true. Gaming graphics cards are optimized for rasterization, and will remain so for many years to come.

Ray’s tracing journey into mainstream gaming began in 2018 with the launch of Nvidia’s line of GeForce RTX desktop cards, in the form of the GeForce RTX 2080. Nvidia introduced the second generation of GeForce RTX 3000 series cards in 2020 (titled GeForce RTX 3080) and quickly followed suit. Competitor AMD followed suit with the Radeon RX 6000 series. (See our review of the flagship Radeon RX 6800 XT.)

AMD Radeon RX 6800 XT

AMD’s Radeon RX 6800 XT competes with the GeForce RTX 3080.

In short, it took so long for ray tracing to enter the gaming scene because the computing resources to pull it were out of reach at prices that would allow mainstream adoption. To be sure, the cost of entry is still relatively high – neither AMD nor Nvidia has yet offered a low-end desktop graphics card with hardware ray tracing. Currently, the “entry level” hardware ray-tracing video card is the GeForce RTX 2060, which was launched in 2019 with an unexpected budget of $349 and is selling way more than most sources these days, due to the high demand for video cards. (And the low supply of them).

The best ray tracing graphics cards we tested…

stay here Some Point, prices will stabilize. And the scene is set for continued mainstream adoption, particularly since the latest gaming hardware joined the party.


Visual improvements with ray tracing

It’s important to realize that ray tracing has only set foot in the gaming graphics door. This is due to file submission entire The game in real-time ray tracing is still far beyond the capabilities of today’s hardware. Games that support ray tracing only use it for certain effects, especially those related to shadows and lighting, while everything else is still pixelated.

First, a quick primer on terminology. Nvidia’s RTX-branded cards—the GeForce RTX 2060 or RTX 3080, for example—use a proprietary graphics rendering application that Nvidia widely refers to as “RTX.” This implementation maybe Use DirectX 12, more specifically DirectX Raytracing API (DXR) to render light paths in the game engine.

DXR, meanwhile, is a ray tracing API that can run independently of, or in combination with, Nvidia hardware. For example, game developers Crysis showed a demo of their Crytek engine several years ago that ran ray tracing reflections on an AMD Radeon RX 5000 series card (a GPU without RT cores on board), although performance was predictably slow. . If you were to run the same demo on an AMD Radeon RX 6000 Series card, complete with RT cores on board, you would process the DXR scene faster.

RT cores help any graphics card, branded AMD or Nvidia, to run DXR faster, but DXR doesn’t need RT cores to run.

Let’s see how ray tracing can improve the game visually. The following pairs of screenshots were taken in Square Enix’s Shadow of the Tomb Raider for PC, which supports ray-traced shadows on Nvidia GeForce RTX graphics cards. Specifically, look at the shadows on the ground.

SOTTR Non Ray Tracing 2

point shadows

Sutter ray tracing 2

Ray tracing shadows (using in-game Ultra setting)

Here’s another pairing of scenes from Shadow of the Tomb Raider…

Sutter non-radial tracing 1

point shadows

Sutter ray tracing 1

Ray tracing shadows (again, with the Ultra setting in-game)

And let’s take a look at the final set…

Non-radial tracking SOTTR 3

point shadows

Sutter 3 . ray tracing

Ray Tracing Shadows (in-game ultra setting)

Ray-traced shadows are softer and more realistic than the harsher point versions. Its darkness varies depending on how much light the object blocks and even within the shadow itself, while rasterization appears to give each object a solid edge. The raster shadows still don’t look bad, but after playing the game with ray tracing shadows, it’s hard to get back into them.

Currently, support for ray tracing in games is somewhat polarized because the feature has to be implemented separately For AMD and Nvidia cards. More games support Nvidia cards mainly because Nvidia was the only company to produce graphics cards capable of ray tracing until 2020, but more games are starting to support both flavors. Recent examples include Cyberpunk 2077, Dirt 5, Godfall, and World of Warcraft: Shadowlands.

Recommended by our editors


Ray tracing: performance effect

When it comes to computer graphics, everything It comes at a price, and the visible ray-tracing stuff is no exception. Enabling it generally results in a performance penalty that varies in its effect from game to game.

Let’s take, for example, the standard built into Shadow of the Tomb Raider. I ran it on a gaming-ready desktop with an AMD Ryzen 9 5900X processor, GeForce RTX 3080 graphics card, and 32GB of memory. The numbers shown below, tested at two resolutions, are average frames per second (fps). A minimum of 60 FPS is required to play smoothly.

The double-digit performance results from ray tracing are important, and note that this is done with the performance-optimized DLSS feature turned on. DLSS is an Nvidia-specific feature supported in certain games that can help reduce the impact on frame rates of ray tracing’s computational load. (For more information on DLSS, see our feature testing Nvidia’s DLSS 2.0: Higher frame rates for free?) DLSS shows great promise, but the game has to support it. While it is gaining momentum these days, support for it is far from universal.

Remember that this performance trade-off only comes from applying shadow and lighting effects, so today’s technology is still a long way from using ray tracing to deliver a full game. However, the performance results are the worst case scenario in this case, since this game has ray tracing shadow settings with less negative impact on performance.

The improvement of the game is worth mentioning. Developers will undoubtedly learn to improve ray tracing better like they did with rasterization, so it should become possible to get more ray tracing effects from existing hardware. (Again, look at how far the dripping has come.)

The main ray tracing games we reviewed

DLSS is one approach that will also help, and we expect DLSS to improve and expand over time. AMD is also working on its own variant to provide performance similar to DLSS, dubbed “Ultra Resolution”. Super Resolution is jointly developed by Microsoft’s DirectML team (“ML” abbreviation for “machine learning”). However, AMD says the technology is still a long way off, and we likely won’t see any games working in it until 2022 at the earliest.


A ray-traced future: slowly gaining strength

Despite the limited applications of ray tracing in today’s games, it is here to stay. The writing has been on the wall since AMD followed Nvidia by offering Radeon graphics cards with hardware ray tracing support. Hardware ray tracing support on Xbox Series X and PlayStation 5 brings this point home.

On that note, ray tracing has been chosen for console players. It’s also designed for PC gamers who buy modern mid-to-high end graphics cards, as all newer models support hardware ray tracing, but the question remains whether gamers with older or lower-end graphics cards should be upgraded, or those in the market should. pony.

atomic heart

In short, there’s no need to invest in a graphics card that supports hardware ray tracing unless you determine that the visual differences are worth the money. Ray tracing currently offers a few other advantages to gaming, so it just boils down to simple enjoyment.

The current limited availability and high graphics card prices make ray tracing a bigger investment than it should be, so unless you’re lucky enough to get a GeForce RTX or Radeon RX 6800 card, it might make sense to keep ray tracing. Wishlist and use coins for games. This strategy could work better in the long run, as you’ll be able to retry any game you’ve purchased that has added ray tracing support while you wait.

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