As the price of 4k displays decreases, many games are competing to join the trend of supporting 4k. For example, " Far Cry 5" in March this year supports native 4k on Xbox One X. To cater to the public, Sony and Microsoft have upgraded their consoles and released the Xbox One X and PS4 Pro. However, in fact, there are many mysteries hidden in it.
For the current image processing system, "the main work done in each frame (processor) is roughly proportional to the number of shadow pixels." said Timothy Lottes, an AMD image engineer. However, although the number of 4k pixels is 4 times that of 1080p, the PS4 Pro is not 4 times stronger than the PS4; so the current hardware is actually not as good as the 4k resolution level - the Xbox One X is not good either. Lottes' calculation results show that if a game wants to reach 30 frames on PS4, it needs to perform about 7.4 Tflops per second (trillions of floating-point operations) under 4k image quality; the PS4 Pro has at most 4.2 Tflops/second, and the Xbox One X has only 6 Tflops/second, and Lottes' calculation is still simplified, and many other factors have not been considered.
So, in order to enable games with only 1080p picture details to output at 4k resolution, the game producer needs to use many small tricks. For example, the racing game "Onrush" actually only renders half of the 4k pixels, which means that it only doubles the difficulty of rendering 1080p images; then a temporary reconstruction technology is used to provide a unified anti-aliasing solution, and then the resolution is "stretched" to 4K, which can fill all the remaining pixels well. Temporary reconstruction is to use the previous few frames to infer the picture and fill it; another similar solution is the checkerboard filling method, that is, rendering it every other pixel, and the effects are similar, but each has its own advantages. Oli Wright, chief graphics programmer of Onrush, said they had only experienced a double resolution change before, and this time they were unable to adapt to it by 3 times, so they used these methods to "pretend" that the resolution was still only doubled.
However, it seems that not all developers are like this, such as Sumo Digital, the producer of "Crackdown3", which has led Microsoft to advertise "real 4k". Although Lottes believes that jumping from 1080p to 4k must have to give up some visual effects - for example, a video compared " Far Cry 2" and "Far Cry 5" and pointed out that the latter cannot achieve dynamic growth trees and larger fires for video fidelity - Sumo head Ash Bennett still firmly stated that they will not sacrifice gameplay because of the pursuit of 4k image quality; he believes that the game process is CPU simulated and will not occupy visual resources.
, and Alex Perkins, the head of Onrush, believes that although they have made adjustments, the visual effects are equally satisfactory and have not affected other aspects of the game. He believes that if they use very realistic grass simulation technology but occupy 50% of the game resources, it is not worth it - unless they are doing grass simulation 2018.
However, even "Rampage-Extinguishing Men 3", it can only run at 30fps in 4k image quality; according to Lottes' calculation, if you want to output 4k images at 60fps, you must have at least 14.7Tflops/second, which is more than twice the upper limit of the Xbox One X. In fact, the current top-notch computers, such as Nvidia Geforce 1080ti and AMD Vega 64, can only reach 11.5 and 13.7 Tflops/second respectively, and still cannot really make 4k+60fps.
For Lottes, high fps is just as important as high resolution because fps determines the smoothness of the action and the instantaneousness of the game's response. Digitally, native 4k 30fps and native 1080p 120fps render the same number of pixels, and he is more concerned with the latter.He believes that if we keep 720p no longer changes, the producers do not need to just use the GPU to fill more pixels, but can perform each existing pixel more perfectly, gradually approaching the visual effects of CG animation;
CG animation
Or, higher quality anti-aliasing and ray special effects can also be used (such as real-time ray tracing technology exhibited by Microsoft and Unreal at GDC this year); or, no visual effects can be even made, but further improved world simulation, strengthen AI, physics engine and other mechanisms to enhance the immersion and interactivity of the game; even in the future, dynamic resolutions that change according to the changes in players' vision, instead of rendering each pixel to the same level as now.
The first game to use real-time ray tracing technology - "The Departure of the Metro"
However, after all, marketing is the biggest factor in determining the sales of the game; for the majority of players, the visible and tangible 4k image quality can attract the players' attention the most; and other advantages of the game often do not have such an intuitive and strong impact. Throughout the history of games, games with good picture quality and good visual effects are often sold. So now, the powerful image quality brought by 4k resolution with unprecedented precision has become the focus and selling point, which is the general trend.
