DirectX Developer Blog

> Ray tracing WILL DEFINITELY fully take over rasterization once hardware capable of doing it is commoditized.

That's not what this demo is about, and what you wish for is decades away at best. DirectX realtime raytracing relies upon a rasterization step to estimate the light for most of the objects on the screen.

https://blogs.msdn.microsoft.com/directx/2018/03/19/announcing-microsoft-directx-raytracing/

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> Not needing to perform all those hacks to approximate what offline renderers can do.

The Gooseberry benchmark (Blender's hardest test) takes 35 minutes to render on my 16-core / 32-thread Threadripper 1950x, while GPUs simply crash because literally one frame of animation requires 12GB of RAM (far more than whats available on commodity GPUs).

Offline renderers are about 5-orders of magnitude too slow for realtime and about 1-order of magnitude of RAM usage too large for conventional ~2GB or 4GB GPUs.

We're at the stage where SOME simplified raytracing effects can replace SOME aspects of the rasterization pipeline, and only if you buy 4x Tesla V100 (Ohhh... that's more expensive. $8k+ per Tesla V100 == $32,000 on GPUs alone). Furthermore, there were only ~1 to ~2 rays per pixel. All the ray-tracing effects were processed through a neural-network to denoise, and they also average those rays through history (so this technique only works on slow-moving objects).

That's what this demo represents. A LOT of compromises, but hey, they achieved a very…

Apple's Metal shader language is C++14 with some restrictions, and extensions (such as native matrix and vector types), implemented with LLVM:

https://developer.apple.com/metal/metal-shading-language-specification.pdf

Microsoft's HLSL is now also based on LLVM:

https://blogs.msdn.microsoft.com/directx/2017/01/23/new-directx-shader-compiler-based-on-clangllvm-now-available-as-open-source/

Khronos has an LLVM-based translator between LLVM bitcode and SPIR-V:

https://github.com/KhronosGroup/SPIRV-LLVM

So things are converging, may be one day GPU extensions will end up in the C++ standard ;)

Please stop propagating FUD: "proprietary RTX tech when there's no way they weren't involved or informed in the development of DirectX Raytracing"

Just looking here and searching for NVIDIA:
https://blogs.msdn.microsoft.com/directx/2018/03/19/announcing-microsoft-directx-raytracing/

yields:
"And, our friends at EPIC, with collaboration from ILMxLAB and NVIDIA, have also put together a stunning technology demo with some characters you may recognize."

Which was rendered with DirectX Raytracing using RTX hardware. Link: https://www.youtube.com/watch?v=J3ue35ago3Y&feature=youtu.be

From an earlier blog post https://blogs.msdn.microsoft.com/directx/2018/03/19/announcing-microsoft-directx-raytracing/

DXR will initially be used to supplement current rendering techniques such as screen space reflections, for example, to fill in data from geometry that’s either occluded or off-screen. This will lead to a material increase in visual quality for these effects in the near future. Over the next several years, however, we expect an increase in utilization of DXR for techniques that are simply impractical for rasterization, such as true global illumination.

"For one, all shaders would need to be converted from HLSL to GLSL, which could become quite a big task depending on the amount of shaders, and testing of all changes."

Ironically Microsoft have open-sourced a Clang-based HLSL compiler that could be used as a front-end for a Vulkan backend.

https://github.com/Microsoft/DirectXShaderCompiler

https://blogs.msdn.microsoft.com/directx/2017/01/23/new-directx-shader-compiler-based-on-clangllvm-now-available-as-open-source/