The "Ultimate" version of DirectX 12, officially launched Thursday by Microsoft and Nvidia, doesn't add much in the way of capabilities to the gaming graphics programming architecture. It mostly wraps together several specific existing programming interfaces into a single update, including:
- Ray tracing (DXR 1.1) for more realistic and easier-to-create reflections, shadows and illumination.
- Variable rate shading, which allows developers to concentrate system resources where they're more important visually.
- Mesh shaders, which gives developers more control over GPU acceleration when it comes to surface complexity for improved performance.
- Sampler feedback, to improve performance by, say, allowing a game to reuse already-rendered textures or bypass rendering of surfaces you can't see, as well as to load textures faster (texture streaming), a big part of the Xbox's SSD support.
Though all that sounds esoteric, in practice it creates a unified programming interface across the upcoming Xbox Series X console and Windows 10 for all the newly hyped acceleration and intelligence algorithms on that console, which is due out at the end of this year. This makes cross-platform game design simpler (at least in some ways for those two), PC graphics-card driver support swifter and — what we really care about — means potentially more games looking more realistic and adding playability without taking a performance hit.
Most notably, it was created in conjunction with Nvidia using the company's experience with its RTX ray-tracing. Thus, many game developers won't have to write to Nvidia's proprietary programming interface in order to take advantage of its features, which has been one factor holding back adoption of features like ray tracing and global illumination.