With the release of GeForce RTX graphics cards, NVIDIA ushered in the era of ray tracing in games. And this was the reason for the ongoing debate about the very expediency of this technology in games. We can definitely say that tracing has not become a mass phenomenon, and the list of compatible games is still small. Soon it will be replenished with the action movie Control, and then the autumn game season will begin, which will also bring something interesting. In anticipation of new games, we decided to talk about tracing in already available projects. Let’s take a look at how beams affect graphics and performance in Battlefield V and Shadow of the Tomb Raider. At the same time, we will study the features of NVIDIA DLSS technology, which, in addition to these games, is also available in Anthem.
What is ray tracing? This is a rendering method that builds and traces the paths of light rays to each point in space. This method allows you to accurately determine the illumination of objects, reflected light and mutual shading. This is another step towards the realism of the virtual image. But ray tracing is extremely resource-intensive, so it was previously unavailable in games. And now this method cannot be fully used. At the moment we are talking about hybrid rendering, which combines standard rasterization with tracing. The latter is used to implement individual effects, for example, to render correct reflections and shadows.
Ray tracing works on Windows 10 (version 1809 and later) through the DirectX Raytracing (DXR) API, which is an extension to DirectX 12. Ray tracing is currently available in Battlefield V, Shadow of the Tomb Raider, Metro Exodus, Stay in the Light, and Chinese MMO Justice. Also, effects based on this technology are promised to be added to Wolfenstein: Youngblood, where everything is implemented in the Vulkan API environment.
The optimal solution for ray tracing is NVIDIA GeForce RTX graphics cards, which have hardware improvements to speed up the corresponding operations, in particular, additional RT blocks. And when talking about tracing, they often operate with the definition of RTX, which hints at the technology and the corresponding video cards. At the same time, all the functions of the DXR API are also supported by older Pascal architecture video cards, which allows you to enable new effects on the GeForce GTX 1080 Ti and other video cards of this series. But without appropriate hardware optimizations, tracing is given to them with huge performance losses.
NVIDIA DLSS technology is not directly related to tracing, so it can be used in games without new effects. This rendering method is used to speed up performance, which is critical when activating RTX effects. And since DLSS uses the hardware features of GPU Turing, the technology works exclusively on GeForce RTX graphics cards.
This review used a system with a GeForce RTX 2080 Ti graphics card. Screenshots and videos in 4K are provided as visual materials. First, we will consider the visual features of the tracing in each game in stages, and at the end we will talk about DLSS.
Ray tracing in Battlefield V
Let’s start with the last part of Battlefield, since it was the first game to support tracing. A new technology was tested on it, and since the release, the developers have done a good job of optimizing, bringing performance with tracing to an acceptable level.
In Battlefield V, a new technology is used for reflections. The game has several levels of tracing quality, which are determined by the DXR settings — low, medium, high and maximum quality. According to information from open sources, these settings affect the number of rays rendered and which surfaces they are applied to. Let’s try to identify the main visual features.
Below is the most striking example of the impact of tracing. The camera position may change slightly due to the need to restart the game and the difficulty of selecting the same angle.
In normal mode, on the water surface, you can see the reflection of the sky and the reflections of the branches and at the edge of the puddle. In this case, everything happens in a grove, and a puddle is surrounded by trees. Activating the simplest DXR option adds reflections of these trees. And the whole scene is perceived somewhat lighter, which is noticeable even by the color of the foliage in the background. Switching to Ultra-quality produces minimal changes — the ripples on the water look different, and there are no light halos around objects in the water.
Let’s see how tracing affects ice and snow. The position of the hero is slightly different, so we do not pay attention to the contours of the snow.
Tracing immediately adds reflections on the ice, which are not originally there. Increasing the quality gives a strange effect when some areas of the ice lighten up. In fact, it acquires a different texture — some areas seem smoother, and some more rough. This is an example of the fact that we get a material with different reflective properties.
Tracing doesn’t just add reflections to puddles and water surfaces. It affects how any wet surfaces, glass, metals and other reflective materials look. At the minimum and medium level, this is felt only on water and wet surfaces. At high and ultra DXR settings, the effect on metal car bodies, environmental elements and other objects is already noticeable. This is clearly visible on the tank hull on the bottom slide. Well, as the quality improves, an increase in the distance where tracing is used is noticeable. At a low DXR level, distant puddles do not change, at a high level they do.
As a final comparison, below is the same scene without tracing and with DXR Ultra.
This scene is interesting in that a bridge hangs from above, blocking the light. But in normal mode, there are bright puddles of light under the bridge, and the puddle in the left corner reflects the sky. With tracing, puddles and wet asphalt change. And although they look darker, the texture of wet asphalt seems more realistic. The body of the tank also looks different.
You can better appreciate the changes in a video comparing graphics in 4K.
Tracing can change the perception of the whole scene, and not just create reflections on the water. Since the game has a lot of locations with mud, puddles, wet asphalt, etc., the general changes are sometimes clearly visible. But this does not affect desert locations and similar levels — reflections appear on the glass, the texture of the metal changes somewhere, but these are minor nuances. With tracing, there is more flame glare from explosions on surrounding surfaces, which makes such scenes brighter.
Read more about performance on the last page.