![]() ![]() Dynamic objects cast a fully dynamic shadow. As a first adjustment, we excluded dynamic and opacity masked objects. (Example showing before and after of Composition after lighting at a coarse pixel size of 4×4)Īfter excluding the passes where VRS is unusable due to artifacts, we began to work on adjusting the shading rate based on other factors. The following passes proved to have a performance improvement from VRS, but had too many artifacts to be worth using: We could have good results in a city during the day, but artifacts in a sand environment with various foliage or at night in the rain. This process was fairly time consuming as Gears Tactics has multiple biomes with multiple types of weather conditions. Next, we examined the severity of artifacts produced in those passes by VRS. Responsible for rendering any direct lights to the scene color buffer. The process to re-use screen-space information for creating reflections.Īnti-aliasing for the results of the Screen Space Reflections pass. Responsible for screen space ambient occlusion and decals.īloom effect generated from light shaft rendering. This pass iterates on shadowed lights with this falloff in mind to render shadow projections. Smooths out translucent meshes within a volume to prevent aliasing issues.Īttenuation is the outer bounds when calculating the falloff of a given light. Lighting for subsurface scattering materials. ![]() To figure out which had the most promise, we enabled VRS on all passes and then narrowed down in PIX the areas that showed a benefit. ![]() Passes that relied on accurate pixel information were one cause of these artifacts. We determined our next step would need to be evaluating which passes had the most promise for gains from VRS and then testing multiple shading rates on those passes and excluding any that had artifacts. We enabled VRS for all draw calls in the base pass and the translucency pass and immediately noticed the artifacts were too severe in the translucency pass. In our initial investigation, the base pass and translucency stood out as large potential for gains compared to most other passes. We found we could benefit from VRS throughout the renderer, including some full screen draws. For more background on VRS, refer to this blog post.īecause our usage of VRS did not extend past tier 1 we needed to determine which rendering passes ( Gears Tactics uses Unreal Engine 4) could support VRS, as well create new ways to determine when to reduce the shading rate. For this reason, our implementation is exclusively Tier 1, which lets us set a shading rate per draw. To support our goal of reducing the hardware barrier to entry, we wanted to include the broadest range of hardware in our VRS implementation. performance.Īvailability of VRS is based on hardware. In this article we’ll detail our process of iterating on VRS to achieve a good balance of quality vs. We landed on Variable Rate Shading (VRS), which gave a generous performance boost with minimal quality loss. This led us to look for new solutions to improve performance that didn’t entirely involve sacrificing visual quality. One of The Coalition’s primary goals on Gears Tactics was to reach a wider audience on PC by reducing the hardware barrier to entry. Gears Tactics is a fast-paced, turn-based strategy game set in the universe of one of gaming’s most-acclaimed franchises– Gears of War. ![]() Iterating on Variable Rate Shading in Gears TacticsĬam McRae, Technical Director at The Coalition Check out this guest post where Jacob Nelson and Cam McRae share implementation details, performance data and future ways to expand VRS. VRS let Gears Tactics achieve large performance gains – up to 18.9% (!) – on a wide range of hardware with a minimal impact on visual quality. Gears Tactics is the very first game to ship with support for DirectX 12 Variable Rate Shading (VRS), one of the major features in DirectX 12 Ultimate. ![]()
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