It was never going to happen overnight, but one thing is for sure—ray tracing is where graphics are headed. The challenge, of course, is the enormous strain that ray-traced rendering has on hardware. However, Microsoft has made a concerted effort to sort of side step the issue with its DirectX Raytracing (DXR) API, and now the company is offering developers a preview of what new tricks and capabilities are to come.
Microsoft's preview is actually a broader overview of a suite of features headed to DirectX 12 (DX12). The one we are most interested in, however, is a new tier of ray tracing support (tier 1.1). They include the following:
- Support for adding extra shaders to an existing Raytracing PSO, which greatly increases efficiency of dynamic PSO additions.
- Support ExecuteIndirect for Raytracing, which enables adaptive algorithms where the number of rays is decided on the GPU execution timeline.
- Introduce Inline Raytracing, which provides more direct control of the ray traversal algorithm and shader scheduling, a less complex alternative when the full shader-based raytracing system is overkill, and more flexibility since RayQuery can be called from every shader stage. It also opens new DXR use cases, especially in compute: culling, physics, occlusion queries, and so on.
Beneath all that technobabble is a set of tools and features intended to help developers better expose the capabilities of graphics hardware, and also "address adoption pain points." In other words, this could help facilitate a faster movement into ray-traced territory.
This could be especially important as AMD jumps on the bandwagon with a future version of Navi. At present, only Nvidia's GeForce RTX series of graphics cards offer dedicated ray tracing hardware to consumers, but that is expected to change next year. We know for sure a version of Navi with hardware-based ray tracing support is headed to the PlayStation 5 at the end of 2020, and we are likely to see the same thing on PC around that time as well.
Microsoft also highlighted some other things headed to DirectX 12, including mesh shaders and amplification shaders. These represent the "next generation of GPU geometry processing capability," technical details of which are laid out in a blog post. Summed up, these could lead to faster load times, particularly at higher resolutions, such as 4K.
