Ray Tracing on Mobile: Fact or Fiction? 

Ray tracing is a common rendering technology present in modern PCs, games, and animated movies (CGIs). The technology is progressively gaining ground on mobile devices as an increasing number of manufacturers have already released their first-generation of mobile devices supporting real-time ray tracing, for example Samsung S22, Xiaomi 13 Pro, Vivo X90 Pro, and Oppo Find X6 etc. While ray tracing on mobile devices has not achieved the same level of widespread adoption as on regular PCs, there is a distinct trend indicating that ray tracing is making its way into the mobile device market. However, is there an evident need for ray tracing on mobile? And can the cost of ray tracing be justified? Or is it just a trendy buzz?  

Before diving further into the discussion about mobile ray tracing, let’s get a clear understanding of what ray tracing really is.   

Ray tracing is an illumination rendering technology enabling the creation of lifelike light and shadow renderings. Ray tracing has been around for a very long time and is commonly employed in movies or animations using 3D CGI. Although, in such cases, we are talking about “offline” ray tracing rather than real-time rendering. Due to the high computing power needed for real-time ray tracing, rasterization has been the preferred technique to use, since it doesn’t require as much processing power, which means that it is more affordable. However, as new more powerful and affordable graphics cards have entered the market, real-time ray tracing is becoming more prevalent. 

With real-time ray tracing nearly having established itself as the new norm on PCs, larger vendors are already implementing the next generation of the technology, known as real-time path tracing.  

However, for mobile devices, the story is a bit different. Due to the notably limited computing power, mobile devices still lag in terms of ray tracing support.   

If we look back at the previous technological advancements, the mobile environment seems to closely follow the same technological trends as in PCs. Consequently, the developments in the PC field are expected to be spread on mobile as well. A similar pattern in trends can be spotted in the evolution of graphics units, multi-core processors, double data RAM, even display screens. 

Previously, many functionalities and applications were developed exclusively for PC; however, today, they are also available on mobile devices. For instance, in the past, video editing could have been considered as a “PC-only job”, but nowadays, it can be accomplished using your smartphone. If basic video editing applications already exist, it’s only logical for users to anticipate the availability of more advanced editing features on mobile applications, like those found on PC versions. Some editing apps have already enabled photorealistic production based on cloud rendering (like; XO3D, Prisma 3D, and Sculptura). Most certainly, this is just the first step, before moving to real-time rendering.  

While the adoption of mobile ray tracing is arguably heavily dependent on consumer demand and established patterns of technological development, a dilemma also arises regarding who will act as the driving force behind this mobile adoption – Is it the vendors, the software developers, or the end users? This is what David Harold, Chief Marketing Officer at Imagination, refers to as a  “chicken and egg problem”. Since ray tracing has such a big impact on the performance, which costs a lot of money for the chip vendor and the manufacturer, they want to be sure that there’s content that supports ray tracing before making substantial investments. But on the other hand, game developers won’t produce ray tracing content, unless there are devices that supports ray tracing. 

Computer games and 3D graphics production are the most common use cases where real-time ray tracing plays an important role. In computer games, ray tracing can be clearly visible due to the “live action” scenes. As for computer graphics, ray tracing significantly diminishes the gap between reality and CGI by introducing a substantial level of realism, primarily through enhanced lighting effects. 

However, what becomes a major factor to take into consideration when evaluating the effect of ray tracing is the size of the screen and resolution. Because one could argue that the most direct connection of real-time ray tracing usage relates, in the end, to the size of the screen. 

The larger the screen, the more details you will be able to see. If the screen is large and you spot a mistake, your eyes will focus entirely on it. But on smaller screens, such as on a smartphone, the impact of ray tracing is of course different. Since the screens are much smaller, it is hard to spot imperfections, which otherwise can be just ignored. However, real-time ray tracing brings additional realism to the scene, which will improve the graphics quality, and ultimately boosts the general experience. It brings that unconsciously perceived dose of realism which can be spotted only when it’s no longer there.  

Of course, in conjunction with the screen size, the other important aspect is the resolution. A physically big screen doesn’t bring that much, unless the device can support a high enough resolution. As seen using the latest ray tracing benchmarks, like GPUScore: In Vitro, the resolution in which the application runs, has a direct impact on the balance between quality and performance. And yes, at really low resolutions, the usage of ray tracing is not justified, because the details that bring the scene closer to reality become barely visible. 

What about ray tracing on tablets then? Unarguably, the gaming experience on tablet is entirely different from the one on smartphones. Despite the fact that technology is gradually establishing a stronger demand for it on smartphones, especially in the context of gaming, the trend seems to be more pronounced on tablets. Since the technology and the platform are fairly the same for both smartphones and tablets, it is fair to refer both devices to fall under the ‘mobile environment’ category. Most probably this is why mobile vendors have already produced the first models featuring real-time ray tracing support, due to the advantages of using ray tracing on tablets.  

Considering the effort that manufacturers put into integrating ray tracing technology on handheld chipsets, the costs for the first generation of the devices are usually high. Ray tracing on mobile is performance demanding and running a full ray tracing range of features at high frame rate is impossible. Considering that ray tracing on mobile is still quite a new technology, the trade-off, between cost and performance, does not come as a surprise.  

 In an article by Androidauthority, they refer to “levels” of ray tracing, as a possible means to administer the cost and performance issue. Some features on mobile might be rendered with ray tracing but not necessarily all, since manufacturers need to take into consideration the impact on performance. Therefore, they assume that just because a smartphone supports ray tracing, it doesn’t necessarily mean that the experience will be the same as on a console or PC.  

Historically looking, the technological advancements on mobile have closely followed the same patterns of the advancements on desktop. Moreover, the graphical improvements in gaming content are constantly pushing the limits of graphics quality, regardless of the environment. As the gap between desktop and handheld will mitigate, the number of applications and games that require real-time ray tracing will grow bigger, which will substantiate the need for ray tracing in the mobile environment.   

If you’re interested in learning more about mobile ray tracing, check our webinar together with Imagination Technologies “The Future of Mobile Ray Tracing and GPU Benchmarking”.