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Re: Realtime raytracing

From: Myles C. Maxfield <mmaxfield@apple.com>
Date: Fri, 28 Dec 2018 08:30:48 -0800
Cc: DevSH Graphics Programming on Gmail <devsh.graphicsprogramming@gmail.com>, iam here <iamhereintheworld@gmail.com>, public-gpu <public-gpu@w3.org>
Message-id: <C01E0B54-1B72-4465-B564-F4A38DE4F5B5@apple.com>
To: Kai Ninomiya <kainino@google.com>
One of the design requirements for WebGPU is that it maps well to each of the platform APIs: Metal, Direct3D, and Vulkan. Metal has MPS[1] for ray tracing, Direct3D has D3D12_RAYTRACING[2], and Vulkan has VK_NV_ray_tracing[3]. Any solution would probably have to work on top of those APIs.

Presumably, any solution would either need a compute shader fallback for the systems that don’t work with the above mechanisms, or support of ray tracing at all will be optional, and applications can implement their own fallback (or just live without it).

[1] https://developer.apple.com/documentation/metalperformanceshaders/metal_for_accelerating_ray_tracing
[2] https://docs.microsoft.com/en-us/windows/desktop/direct3d12/direct3d-12-raytracing
[3] https://www.khronos.org/registry/vulkan/specs/1.1-extensions/html/vkspec.html#VK_NV_ray_tracing

> On Dec 22, 2018, at 10:44 AM, Kai Ninomiya <kainino@google.com> wrote:
> 
> (3rd retry sending this email is the charm, had a typo in the group's address)
> 
> Unfortunately, WebCL is long dead, and there are no longer any implementations. However, a polyfill or implementation of raytracing atop compute shaders would be good as it would make this functionality much wider reaching.
> 
>> On Sat, Dec 22, 2018, 4:41 AM DevSH Graphics Programming on Gmail <devsh.graphicsprogramming@gmail.com wrote:
>> You can already use Radeon Rays for similar functionality.
>> Most probably the Vulkan backend could be ported to WebGPU.
>> 
>> Furthermore it uses OpenCL as one of the backends, so as long as you
>> code a workaround for the lack of mapping you could even do realtime
>> raytracing in webCL with emscripten.
>> 
>> On 22/12/2018 02:08, Kai Ninomiya wrote:
>> > It's possible in the future. Once:
>> > - WebGPU is closer to finalization
>> > - Raytracing APIs have matured some more across the native APIs
>> > then we would welcome an in-depth investigation into how a raytracing
>> > extension could be added to WebGPU (a proposal for an API that can be
>> > implemented efficiently and securely on top of all relevant native APIs).
>> > 
>> > On Fri, Dec 21, 2018 at 11:32 AM iam here <iamhereintheworld@gmail.com
>> > <mailto:iamhereintheworld@gmail.com>> wrote:
>> > 
>> >     Hi,
>> >     I'm curious to know if it will someday be possible to do realtime
>> >     raytracing on the new Nvidia RTX cards, using WebGPU (and also,
>> >     subsequently, on AMD's, whenever they launch an equivalent)?
>> > 
>> >     Thanks.
>> > 

Received on Friday, 28 December 2018 16:31:18 UTC

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