Microsoft announced this week its DirectX Raytracing (DXR) 1.2 application programming interface, which introduces new features that significantly improve visual quality and rendering performance by up to 2.3 times. AMD, Intel, Nvidia, and Qualcomm, along with game developers like Remedy, are working to integrate DXR 1.2 technologies into future gaming hardware and software.
The DirectX Raytracing 1.2 update includes Opacity Micromaps (OMM) and Shader Execution Reordering (SER), two technologies that boost performance in raytraced games by 2 (SER) to 2.3 times (OMM). Both technologies must be implemented into actual games or game engines to experience the performance benefits.
2X – 2.3X performance boost
One of the main issues with alpha-tested geometry (foliage, fences, hair, etc.) in raytracing is extra calculations required for light to determine whether it hits a surface or passes through. Opacity Micromaps (OMM) improve how alpha-tested geometry processes by applying a texture with an alpha channel to a flat surface. It then removes pixels below a certain transparency threshold. OMM reduces the number of times shaders need to be used, leading to higher efficiency and performance.
In the best-case scenario, Microsoft claims an improvement of 2.3 times. However, keep in mind that not all games and scenes contain a lot of elements like foliage and fences. For example, while S.T.A.L.K.E.R. 2 has loads of grass, leaves, and fences in practically all scenes, Cyberpunk 2077 barely has any foliage.
Shader Execution Reordering (SER) seems to be a more universal feature as it reorders how shaders are executed to avoid shader divergence. Shader divergence occurs when nearby pixels require shaders to do different tasks, a common situation in scenes with heavy raytracing effects, such as complex lighting, realistic shadows, and detailed reflections.