March 24, 2020
Microsoft is debuting DirectX 12 Ultimate, giving developers access to the hardware features on the Xbox Series X and PC. As its next-gen DirectX gaming APIs for Xbox and Windows, DirectX 12 Ultimate enables several methods for improving performance and visuals and brings together Microsoft’s latest development and hardware features while retaining backward compatibility with older consoles and GPUs. Among the improvements are new capabilities for ray tracing, variable rate shading and sampler feedback.
VentureBeat reports that, “Microsoft thinks [DirectX 12 Ultimate] will lead to a ‘virtuous cycle’ where developers no longer hold back their support for hardware features.” In a blog post, the company writes that, “when Xbox Series X releases, there will already be many millions of DX12 Ultimate PC graphics cards in the world with the same feature set, catalyzing a rapid adoption of new features … and when Xbox Series X brings a wave of new console gamers, PC will likewise benefit from this vast surge of new DX12 Ultimate capable hardware.”
Those new capabilities include support for DirectX Raytracing 1.1, which lets games “call on light rays from the GPU without first pinging the CPU,” a more efficient method for the engines to “spool up more ray tracing shaders as players move around an environment.” An alternative is inline ray tracing, which lets artists “pick and choose how the ray tracing behaves” and is also “useful for confined shadows.”
“Scenarios with many complex shaders will run better with dynamic-shader-based ray tracing, as opposed to using massive inline ray tracing uber-shaders,” said the company. “Meanwhile, scenarios that have a minimal shading complexity and/or very few shaders will run better with inline ray tracing.” Microsoft has also collaborated with Nvidia “to ensure that DirectX Raytracing 1.1 takes full advantage of RTX video cards.”
DirectX 12 Ultimate is also better at variable rate shading, a technique for improving performance that lets a game “dynamically tune down the detail on certain parts of a single frame render,” thus spending “less of a GPU’s power drawing the shadowy parts of a room when players can’t really see the details in that area anyway.” According to Microsoft, mesh shaders lets the GPU “control how it manages the level-of-detail,” a method that is “more flexible and simpler than previous geometry tools.”
Sampler feedback reduces “load times and stuttering by more efficiently loading in assets,” allowing the streaming system “to make more intelligent, precise decisions about what data to stream in next … [and allowing] games to render larger, more detailed textures while using less video memory.” Sampler feedback also enables texture-space shading, which allows “a developer to calculate light for a texture without actually having to render it.”
Although Microsoft hasn’t given a release date for DirectX 12 Ultimate, “it’s a big part of the Xbox Series X … so expect it to begin rolling out before this holiday.”