What is ray tracing, and how will it change games?


Ray tracing is a lighting technique that brings an extra level of realism to games. It simulates the way light is reflected and refracted in the real world, providing a more believable environment than is typically seen in more traditional games using static lighting. But what is ray tracing, exactly? And most importantly, how does it work?

A good graphics card can use ray tracing to increase immersion, but not all GPUs can handle this technology. Read on to decide whether ray tracing is necessary for your gaming experience and whether it justifies spending hundreds on an upgraded GPU.

virtual photon

To understand how the revolutionary lighting system of ray tracing works, we have to step back and understand how games previously provided light and what needs to be simulated for a photorealistic experience.

Games without ray tracing rely on static “baked in” lighting. Developers place light sources in an environment that emits light evenly across any given scene. In addition, virtual models such as NPCs and objects do not contain any information about any other models, requiring the GPU to calculate lightweight behavior during the rendering process. Surface texture can reflect light to mimic glare, but only light emitted from a stationary source. compare the reflections gta v As an example below.

Overall, GPU developments have helped this process become more realistic in appearance over the years, but games are still not photorealistic in terms of real-world reflections, refraction, and general illumination. To accomplish this, the GPU needs the ability to detect virtual rays of light.

In the real world, visible light is a small part of the electromagnetic radiation family that is perceived by the human eye. It consists of photons that behave as both a particle and a wave. Photons have no real shape or size – they can only be created or destroyed.

That said, light can be recognized as a stream of photons. The more photons you have, the brighter the perceived light will be. Reflection occurs when photons bounce off a surface. Refraction occurs when photons – which travel in a straight line – pass through a transparent material and the line is redirected, or “bent”. The destroyed photons can be considered as “absorbed”.

Ray tracing in games attempts to emulate the way light works in the real world. It traces the path of simulated light by tracking millions of virtual photons. The brighter the light, the more virtual photons the GPU has to calculate, and the more surfaces it reflects, refracts, and scatters further away.

Minecraft RTX Ray Tracing Beta
Ray tracing alone makes a huge difference in Minecraft. Matthew Smith / Nerdshala

The process is nothing new. CGI has used ray tracing for decades, although the process required fields of computers in the early days to produce a complete film, which could take hours or even days to render a single frame. Now home PCs can emulate ray-trace graphics in real time, taking advantage of hardware acceleration and clever lighting tricks to limit the number of rays to a manageable number.

But here’s the real eye opener. Like any movie or TV show, scenes in CGI animation are typically “shot” using different angles. For each frame, you can move the camera to capture the action, zoom in, zoom out, or pan the entire area. And like animation, you must manipulate everything on a frame-by-frame basis to simulate movement. Grind all the footage together and you have a flowing story.

In games, you control a single camera that is always in motion and always changing perspective, especially in fast-paced games. In both CGI and ray-traced games, the GPU must not only calculate how light is reflected and refracted in any given scene, but it must also calculate how it is captured by the lens – your point of view. For games, this is a huge amount of computational work for a PC or console.

Unfortunately, we still don’t have consumer-level PCs that can actually render ray-traced graphics at high framerates. Instead, we now have hardware that can effectively cheat.

let’s be real

Ray tracing’s fundamental similarity to real life makes it an extremely realistic 3D rendering technique, even in blocky games like making Minecraft Look near photo-realistic under the right conditions. There’s only one problem: it’s extremely hard to emulate. Recreating the way light works in the real world is complex and resource-intensive, requiring computing power.

So existing ray-tracing options in games, such as Nvidia’s RTX-powered ray tracing, aren’t true to life. They are not actual ray tracing, whereby each point of light is simulated. Instead, the GPU “cheats” by using multiple smart approximations to deliver something close to the same visual effect, but without the tax on the hardware. This will likely change in future GPU generations, but for now, it’s a step in the right direction.

Most ray tracing games now use a combination of traditional lighting techniques, commonly called rasterization, and ray tracing on specific surfaces such as reflective puddles and metalwork. battlefield v A great example of this. You see the reflection of soldiers in the water, the reflection of the terrain on the plane and the reflection of the explosions in the paint of the car. It is possible to show reflections in modern 3D engines, but not at the level of detail shown in the game battlefield v When ray tracing is enabled.

Ray tracing can also be taken advantage of to make shadows look more dynamic and realistic. you will see that it had a great effect shadow of the tomb raider.

Ray-traced lighting can create more realistic shadows in dark and bright scenes, with softer edges and more definition. It is extraordinarily difficult to achieve that look without ray tracing. Developers can only fake it through careful, controlled use of preset, steady light sources. Keeping All These “Stage Lights” From very Time and effort – and yet, the result is not perfect.

Some games go completely hog and use ray tracing for global illumination, effectively ray-tracing the entire scene. But it is computationally most expensive and needs the most powerful modern graphics card to run effectively. subway getaway Uses this technique but the implementation is not perfect.

Because of that, semi-measures such as only ray-tracing shadows or reflective surfaces are popular. Other games take advantage of Nvidia techniques such as denoising and deep learning to improve super sampling performance and cover some of the visual hiccups that result from rendering fewer rays than needed to actually create a ray-traced scene. There are. They are still reserved for pre-rendered screenshots and movies where high-powered servers can spend days rendering a single frame.

hardware behind rays

To handle these relatively modest implementations of ray tracing, Nvidia’s RTX 20-series graphics cards introduced hardware built specifically for ray tracing.

RT cores were introduced alongside Nvidia’s CUDA and Tensor cores – featured on Nvidia’s Turing architecture – 20-series GPUs. RT cores are only meant to handle real-time ray tracing. In the Turing card, the RT Core performed decently, but it wasn’t until the recent Ampere launch where we saw them shine.

Nvidia released a breakdown to generate a frame of subway getaway, where it showed how the rendering pipeline is laid out and how it is affected by ray tracing. While an RTX 2080 and a GTX 1080 Ti may be roughly comparable in performance for non-ray-traced games, when ray tracing is applied to a scene, a 1080 Ti without dedicated RT cores can generate It may take longer. same image.

Dedicated RT cores were a big selling point in the RTX 20-series GPUs, but they didn’t quite deliver the performance Nvidia suggested. Even the last-gen 2080 Ti struggled with supported ray tracing titles at launch. However, the new RTX 3080 and 3090 have new RT cores, and the performance improvement is obvious. These cards are not only faster than their previous-gen counterparts, but the new RT cores are also faster. In many ways, the RTX 30-series cards feel like the GPUs Nvidia was promising with the RTX in the first place.

However, Nvidia’s ray tracing method isn’t the only option available. There are also post-processing “path tracing” effects that provide comparable visuals without anything like a similar performance hit.

AMD now also has ray tracing options, which we’ll get to next.

You’ll still want a powerful graphics card for ray tracing no matter what the implementation, but as the technology catches up with game developers, we may be seeing a wider range of supporting hardware at more affordable prices.

What about AMD?

AMD Radeon RX 6000

AMD has struggled over the years to deliver hardware-accelerated ray tracing, but that has changed with the launch of the RX 6800, 6800 XT and 6900 XT. These new cards feature DirectX 12 ray tracing support, and deliver excellent performance, even if AMD isn’t quite at Nvidia’s level in the ray-tracing department (our RX 6800 XT vs. RTX 3080 and RX 6900 XT vs. RTX 3090). Read the comparisons) for more details).

Hardly a surprise considering the Big Navi architecture that powers AMD’s RX6000 card, this is the first generation of ray tracing acceleration. It’s the same architecture that powers the visuals in the PS5 and Xbox Series X, making for a lower level of overall performance than Nvidia’s flagship cards. However, because ray tracing is a standout feature on next-gen consoles, we expect better support and optimization going forward. In the near future we will see the introduction of AMD FidelityFX Super Resolution (FSR) for gaming PCs and the latest versions of Microsoft Xbox.

How can you do ray tracing at home?

You will need a recent and expensive graphics card to view ray tracing at home. Hardware-accelerated ray tracing is only available on the Nvidia RTX 20-series and…

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