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If you know of a way to portably expose ray tracing even on just the GPUs that actually support it, feel free to tell me (or anyone for that matter). AFAIK the

If you know of a way to portably expose ray tracing even on just the GPUs that actually support it, feel free to tell me (or anyone for that matter). AFAIK the problem of abstracting over the different stuff Nvidia and AMD call "ray tracing" is currently an open research problem. Of course you could respond that portability isn't important if you only care about delivering the best graphics you can on given hardware, but if you're really willing to write totally different pipelines for newer AMD cards, newer Nvidia cards, older cards, consoles, etc. you are probably not in the target audience for WebGPU. (BTW, the biggest reason stuff like wgpu-rs doesn't support geometry shaders on non-Metal is that they're horribly slow on a bunch of GPUs, with vendors indicating that they found it super hard to profitably support them in hardware. That's why Metal removed them entirely. I think all the features of geometry shaders that are actually reliably fast, as well as the stuff required to integrate with tessellation shaders, will almost certainly come eventually in other forms. This is an example of why if you care about performance and portability you shouldn't just dump every feature under the sun into your abstraction layer).

pjmlp 4y ago
You can start by using Unreal 5 with Nanite. Yes it isn't quite the same thing, it is however a good example of what Web 3D APIs will never offer, not in 2022, or even in a decade. Unreal 5 with Nanite doing pixel streaming via Azure Cloud Gaming, or WebGPU 1.0, I know which one I would rather play with.
- Jweb_Guru 4y ago
  First, you're talking about a full-fledged game engine (and one that's not actually free or usable by many projects, BTW!) by a huge team that can optimize individually for each platform (and doesn't actually support some platforms at all, e.g. Mac; you may not care about supporting such platforms, but that doesn't mean everyone can afford that luxury). I am talking about a portable low-level graphics API that smaller development teams can use to build their own stuff without needing to rewrite their pipelines for each new target platform. Second, you're also talking about a game engine that does not portably expose ray tracing GPU features; stuff like Nanite that optimistically takes advantage of the hardware where it's available to accelerate ordinary software rasterization is not even close to the same thing. This is a really weak argument. The truth is that neither you, nor I, nor (right now) anyone else knows how to expose that hardware portably, it's all incredibly custom and will probably need big rewrites for each new hardware release. You're complaining about an API not doing something that nobody actually knows how to do yet. Finally, not every application wants to or is able to be rendered in the cloud. It's incredibly expensive to rent out GPUs if you're not being subsidized, and in fact even most AAA attempts haven't worked out economically. Plus not every application can deal with the server latency, or wants to be beholden to an always-online server, or has clients who can tolerate the bandwidth required, or a myriad of other things. So that isn't a solution to a portable low-level graphics API either. I'm not saying WebGPU is perfect, but driveby comments like yours that imply it's missing obvious stuff or handicapped or whatever are pretty annoying. It's a very good attempt at a very difficult goal (efficient, portable, low-level graphics) that has value to a lot of people. It isn't going to be everything to everybody (and neither is UE5, incidentally). When there is a portable way to expose raytracing functionality I have no doubt it will come to WebGPU, but until then it's basically a meaningless gotcha.

pjmlp 4y ago

You can start by using Unreal 5 with Nanite. Yes it isn't quite the same thing, it is however a good example of what Web 3D APIs will never offer, not in 2022, or even in a decade. Unreal 5 with Nanite doing pixel streaming via Azure Cloud Gaming, or WebGPU 1.0, I know which one I would rather play with.

Jweb_Guru 4y ago
First, you're talking about a full-fledged game engine (and one that's not actually free or usable by many projects, BTW!) by a huge team that can optimize individually for each platform (and doesn't actually support some platforms at all, e.g. Mac; you may not care about supporting such platforms, but that doesn't mean everyone can afford that luxury). I am talking about a portable low-level graphics API that smaller development teams can use to build their own stuff without needing to rewrite their pipelines for each new target platform. Second, you're also talking about a game engine that does not portably expose ray tracing GPU features; stuff like Nanite that optimistically takes advantage of the hardware where it's available to accelerate ordinary software rasterization is not even close to the same thing. This is a really weak argument. The truth is that neither you, nor I, nor (right now) anyone else knows how to expose that hardware portably, it's all incredibly custom and will probably need big rewrites for each new hardware release. You're complaining about an API not doing something that nobody actually knows how to do yet. Finally, not every application wants to or is able to be rendered in the cloud. It's incredibly expensive to rent out GPUs if you're not being subsidized, and in fact even most AAA attempts haven't worked out economically. Plus not every application can deal with the server latency, or wants to be beholden to an always-online server, or has clients who can tolerate the bandwidth required, or a myriad of other things. So that isn't a solution to a portable low-level graphics API either. I'm not saying WebGPU is perfect, but driveby comments like yours that imply it's missing obvious stuff or handicapped or whatever are pretty annoying. It's a very good attempt at a very difficult goal (efficient, portable, low-level graphics) that has value to a lot of people. It isn't going to be everything to everybody (and neither is UE5, incidentally). When there is a portable way to expose raytracing functionality I have no doubt it will come to WebGPU, but until then it's basically a meaningless gotcha.