Living in the real world, few people pay attention to all kinds of light. The reflection and refraction of sunlight, the reflection in the lake, the flashing light of neon lights, the light in the room through the light-transmitting window, although the different forms of light are inconspicuous, they make the world full of fireworks.
In contrast to the virtual world in the game, no matter how clear the picture is and how moving the characters are, it always makes people feel that there is a lack of realism. Someone once summed up the difference between the virtual world and the real world, and the contrast brought by light was emphasized. The light in the virtual world is often direct, lacks reflection and diffraction, lacks light and shade, depth and shadow, and lacks the overall sense of three-dimensionality.
In order to make the picture in the game more realistic, NVIDIA released the Turing-based graphics card three years ago, adding “ray tracing technology” that simulates the effect of light in the real world, which is the so-called ray tracing.
At the PC-side light-chasing graphics card conference, computer-side games have entered a new era, and countless netizens are immersed in the realistic world of light-chasing effect rendering. On the mobile phone side, the light tracking technology did not make players wait long.
Last week, mobile phone chip manufacturer MediaTek released a mobile ray tracing solution that uses new hardware image processing combined with ray tracing features to achieve a leap in image quality with lower power consumption.
How is light tracking technology implemented?
In middle school physics, the principle of light propagation has been introduced: light will have refraction, reflection and shadow effects during the propagation process, and light tracing technology is to use existing principles to trace the propagation direction of light and apply it to visual screen rendering. Specifically, the method of photon propagation is used to calculate the irradiation path of light in the environment and the reflection effect formed after collision with the object. After the calculation is complete, the system knows where it is bright, where it is dim, and where it is illuminated by the first light reflection.
To give a simple example, we usually see realistic special effects in movie theaters, and many of them use ray tracing technology. Many scenes do not exist in the real world, but they look “realistic” on the big screen.
The computer-side ray tracing technology was first proposed by Microsoft, which was specially used for 3D rendering. Unfortunately, Microsoft did not study this technology in depth, so that few people were interested in it for a long time. The change appeared in 2018. Nvidia, which is mainly engaged in the research and development of graphics cards, launched the RTX 2080Ti graphics card that supports real-time ray tracing technology in August of that year, which is known as the biggest revolution and success in the graphics card industry in the past 12 years.
As we all know, NVIDIA is a great graphics card company, and graphics cards are the core of computer-side image rendering. After the launch of NVIDIA’s ray tracing graphics card, many game masterpieces have supported ray tracing. In those few years, graphics cards that did not support ray tracing were hardly qualified to be called masterpieces of the year. When many game masterpieces use the light tracking technology, players find that the sense of realism and layering has become better, very close to the light and shadow effects in the real world. Once players use the ray-chasing graphics card, it is difficult to leave it.
Features of mobile ray tracing technology
There is no doubt about the effect of NVIDIA’s light-chasing graphics card, but it is relatively far away for ordinary players. The price of a graphics card that supports light tracking technology is at least several thousand dollars. Adding hardware such as CPU and hard disk, it will cost at least tens of thousands of yuan to save a computer that supports light tracking technology.
At the same time, light tracking technology is not perfect. Ray rendering is so complex that even the most advanced graphics cards cannot simulate hundreds of ray transport trajectories. The reason why the ray tracing effect in blockbuster movies is close to reality is that it is not a real-time ray tracing screen, and the film and television post-production workers have enough time to perform ray tracing rendering on the existing video.
The ray tracing technology on the graphics card belongs to real-time ray tracing, and it is difficult to process a large number of samples in a short time, and the real-time rendering effect is naturally greatly reduced. In addition, the addition of RT Core to the graphics card has an extremely large amount of calculation, which affects the rendering effect of the graphics card itself. Many netizens reported that the number of game frames plummeted by 70% after the light chase.
The computer graphics card can’t handle the real-time light chasing technology, so how should the mobile graphics card handle it? In fact, MediaTek used a tricky method here.
If you follow NVIDIA’s route, MediaTek needs to develop high-performance GPUs, and then divide a part for light tracing calculations. However, the performance of the MediaTek processor GPU is not excellent, and if a part is divided, the screen Display effect will lag behind competitors such as Qualcomm and Apple.
As a result, MediaTek creatively came up with a ray tracing SDK toolkit, combined with the ray tracing rendering pipeline tailored by Tencent Games for mobile platforms, so as to realize mobile ray tracing. Technically, the MediaTek optical tracing SDK is extended based on the Vulkan optical tracing extension specification.
The Vulkan ray tracing standard is an open, cross-platform, and cross-vendor ray tracing standard. Based on it, MediaTek cooperates with the downstream game manufacturer Tencent to provide customized ray tracing improvements for specific games.
In terms of display effect, according to the test video released by MediaTek, the game screen on the mobile terminal is significantly improved, and the light effect is very immersive. However, the real-time display effect may be somewhat different from the test video. Considering that MediaTek adopts a software toolkit solution, theoretically, the light-chasing effect is not as good as that of NVIDIA’s light-chasing graphics card.
It is difficult to evaluate the effect of MediaTek light tracking before the official experience. However, MediaTek’s release of optical tracking technology itself is a huge breakthrough, which symbolizes the first time that mobile chip manufacturers face up to the demand for optical tracking. In the future, chip manufacturers such as Qualcomm, Apple, and Samsung may follow suit one after another, and the era of popular light chasing for mobile games is just around the corner.