Microsoft announces DirectX Raytracing ray tracing API

GDC 2018 started today , and the first major announcement at it was made by Microsoft together with its partners.

An important new functional part will be added to the DirectX 12 graphics API - DirectX Raytracing ( DXR ). Under this name is a new standard API for ray tracing under DirectX with support for hardware and software acceleration.

As you know, ray tracing) For a long time it was considered poorly applicable in real-time applications (for example, in games) as a technology due to low practical productivity. If a conventional raster render converts a 3D scene into a 2D image using various shaders and layers to emulate lighting, then in the case of ray tracing , the interaction of individual rays with surfaces is simulated and the reverse path of the ray propagation is monitored, as a result of which all associated with reflection rays, etc. ( bounces, refractions, reflections ). Well, apparently, the time has finally come.


In turn, NVIDIA announced RTX technology for ray tracing on Volta GPUs and higher, which will be fully supported by DXR (meaning that in this case all RTX functionality is available as a graphical API).

The most important thing: all this can already be felt - links to download the experimental SDK are available at the bottom of the post , examples are included. You will need to participate in the Windows Insider Program and the Windows 10 Redstone 4 (RS4) build .

The DXR instruction set will support the new and existing hardware, and will also allow everyone to write GPU-optimized racers. Due to the fact that DXR will be an extension of the existing functionality of DirectX 12, DXR is closely integrated with rasterization - developers will be able to mix the two rendering technologies for their needs in order to achieve the desired results and performance.

For currently released graphics cards that support DirectX 12, DXR will work in full fallback mode. This is done so that everyone can start developing for the new API right today, and at the same time make sure that applications using the API can be run on "old" video cards. A full-fledged release of the API is scheduled for fall and is likely to take place before the end of this year.

DXR will work with software acceleration on video cards up to Volta, and with hardware - for all cards starting from Volta. AMD is currently working on a driver to support the technology.



Regarding NVIDIA’s RTX technology, it should be noted that its technical details are not yet disclosed. Needless to say, RTX support will be added to all major game engines, and there will also be support for game rates in GameWorks. The announcement of NVIDIA itself was leaked from the briefing a few days ago.



DirectX 12 was announced at GDC 2014 and became part of the Windows 10 release, but is still in the early adoption phase."; there are several reasons for this, and one of them is that DirectX 12 laid the foundation for a low-level API. Now the reasons for this step are becoming clearer - presumably, the DirectX team will continue to add new APIs on top of this foundation in the future.



We will probably learn the rest of the details soon: Microsoft has planned several reports at the GDC that will affect the DXR - the most attention among them is attracted by DirectX: Evolving Microsoft's Graphics Platform . In addition, many game studios and companies that create computer engines will probably share information at their presentations (they had about a year to get acquainted with the technology) - after all, among them are Epic Games, Futuremark, DICE, Unity, Electronic Arts , Remedy and 4A Games.

The official announcement of DirectX Raytracing API
Post with links to download the SDK
Detailed announcement of DirectX Raytracing API
Detailed announcement of NVIDIA RTX
Article by Remedy (authors Max Payne, Alan Wake and Quantum Break, in the past - demosceners)
Slides from Remedy with GDC 2018
Short review of DirectX Raytracing API in English