Microsoft Announces DirectX Raytracing Ray Tracing API

Today GDC 2018 started, and Microsoft made the first serious announcement on it together with its partners.

DirectX Raytracing ( DXR ) will be added to the DirectX 12 graphics API. Under this name is hiding a new standard ray-tracing API for DirectX with support for hardware and software acceleration.
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As is known, ray tracing ( ray tracing ) has long been considered weakly applicable in real-time applications (for example, in games) by virtue of its low practical performance. If a regular raster render translates a 3D scene into a 2D image using different shaders and layers to emulate lighting, in the case of ray tracing , the interaction of individual rays with surfaces is simulated and the reverse ray propagation trajectory is tracked, and all the related with reflection beams, etc. ( bounces, refractions, reflections ). Well, apparently, the time has finally come.


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

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

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

For currently released video cards that support DirectX 12, DXR will work in full fallback mode. This is done so that everyone can start developing for a new API right today, and at the same time make sure that applications using the API can be run on “old” video cards. Full API release is scheduled for autumn and will certainly take place before the end of this year.

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



Regarding NVIDIA's RTX technology, it should be noted that at the moment its technical details have not yet been disclosed. Needless to say, RTX support will be added to all major game engines, and also support for RayTressing in GameWorks will appear. NVIDIA's announcement itself was leaked from a briefing a few days ago.



DirectX 12 was announced at GDC 2014 and became part of the release of Windows 10, but still is still in the stage of " early adoption "; The reasons for this are known, there are several of them, and one of them is that DirectX 12 laid only the foundation of 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.



The rest of the details we will probably find out soon: Microsoft has scheduled several reports at GDC that will affect DXR - the most attention among them is attracted by DirectX: Evolving Microsoft's Graphics Platform . In addition, many gaming studios and computer engine companies will surely share information on their presentations (they had about a year to become familiar with the technology) - after all, Epic Games, Futuremark, DICE, Unity, Electronic Arts , Remedy and 4A Games.

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