VRS, or Variable Rate Shading, was featured in both Gears 5 and Gears Tactics with its Tier 1 implementation. In a new blog post published on the DirectX 12 developer site, Chris Wallis (Senior Software Engineer at The Coalition) explained that both games have now had their VRS implementation upgraded to Tier 2, enabling even better performance. During the tests, The Coalition noticed a 14% performance boost in Gears Tactics when using a 6900XT GPU at 4K with Insane Settings and Quality VRS.
Tier 2 VRS is available on all hardware supporting DirectX 12 Ultimate, including Xbox Series X|S, AMD Radeon RX 6000 Series graphics cards, and NVIDIA GeForce RTX 20 Series and 30 Series GPUs.
VRS for different rendering passes
This is a list of passes that we applied VRS to:
- Base Pass: Renders all opaque meshes
- Screen Space Ambient Occlusion: Use screen-space information to approximate areas that should receive less light due to occlusion.
- Lighting: Calculate lighting for all light sources on the visible opaque meshes.
- Screen Space Global Illumination: Use screen-space information to calculate bounced lighting.
- Screen Space Reflections: Use screen-space information for creating reflections.
- SSR Temporal AA: Anti-aliasing for the results of the Screen Space Reflection pass.
- Translucency: Renders all translucent meshes.
Many of the above match the same passes we applied VRS to in Gears Tactics with our Tier 1 implementation, but one interesting pass to call out is Translucency. Tier 1 VRS applied to Translucency caused artifacts too severe to apply VRS due to the reliance on translucency for some UI effects. However, with the extra control enabled in Tier 2, we were able to bring back VRS to Translucency. Tier 2 VRS ensured UI elements in the translucency pass maintain their crispness while particles, like dust are good candidates for coarse shading.
Performance Results
For PC we allowed VRS to be tuned with 3 different video settings: Quality, Balanced, and Performance. Quality matches what is used by default on Xbox Series X|S and targets no perceptual impact. Balanced similarly targets a minimal amount of perceptual difference, but under scrutiny may show some differences in favor of extra performance. Performance is an aggressive use of VRS that makes some visible compromises but gets back the most performance.
So far, not many games have implemented Variable Rate Shading in general, let alone its Tier 2 version. However, we do already know that Ubisoft’s Far Cry 6 will feature support for it.
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