Dxr

DirectX Raytracing (DXR) is a Microsoft API extension to DirectX 12 that enables real-time ray tracing in graphics applications and games. Introduced as part of the DirectX Raytracing initiative, DXR provides a programmable ray tracing pipeline alongside the traditional rasterization pipeline. Developers write shaders for ray generation, closest-hit, any-hit, miss, and intersection stages, and can also use callable shaders to run custom programs on the GPU during ray tracing.

DXR relies on acceleration structures to speed up ray traversal: bottom-level acceleration structures containing geometry and top-level acceleration structures representing scene instances. The API integrates with Direct3D 12, allowing a unified workflow with existing rendering techniques and permissions for denoising and post-processing.

Hardware and software requirements: DXR requires a compatible GPU with ray tracing hardware support and Windows 10/11. Support began with NVIDIA RTX GPUs and later extended to AMD RDNA 2, Intel Xe, and other DXR-capable architectures, along with driver and OS updates to expose DXR features. Many game engines and applications implement DXR-based effects such as ray-traced reflections, shadows, ambient occlusion, and global illumination in hybrid form with rasterization.

Versioning and ecosystem: The standard has evolved through several versions, adding features like asynchronous shading, denoising, and improved memory handling. It is often associated with DirectX 12 Ultimate in Windows builds and is supported by major engines such as Unreal Engine and Unity, enabling real-time ray tracing within common development workflows.

Impact: DXR popularized real-time ray tracing on consumer hardware and influenced rendering approaches, performance optimization, and the broader adoption of ray-based effects in games and simulations.