[HN Gopher] The Piet-GPU Vision
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The Piet-GPU Vision
Author : adwn
Score : 67 points
Date : 2020-12-11 08:08 UTC (1 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| nemo1618 wrote:
| Gotta say, I was hoping this was an implementation of Piet that
| ran on the GPU: https://www.dangermouse.net/esoteric/piet.html
| boothby wrote:
| Glad I wasn't the only one! I could probably shoehorn a cuda
| backend into repiet... but I don't even know where to start on
| generating optimized code from this horrible stack-based
| language.
| 6d65 wrote:
| I've been playing with OpenCL lately. Is such a shame that the
| support is so spotty, and even Apple(who I think started it,
| probably as a CUDA alternative for their AMD cards), are
| deprecating it.
|
| Even with it not being able to squeeze all the perf from a
| device, it's still handy, especially being a cross device api.
|
| It would've been ideal for piet, especially since compute kernels
| can also be run on CPU on all cores, given a CPU driver. And I
| think some OpenCL implementations support spirv. So it wouldn't
| have needed any fallbacks, the same kernels would run either on
| CPU or GPUs.
|
| I'm still going to use it for my project. But, it's a shame that
| AMD RoCm OpenCL doesn't support running kernels on their CPUs.
|
| Also, Rust might benefit from something like SYCL. There is some
| attractive convenience in having a DSL built into the language
| for parallel computing. But one can dream.
| littlestymaar wrote:
| I have one question in case Raph passes by:
|
| Isn't that a bit risky to go this deep? If I understand things
| correctly, you are currently trying to build a font editor in
| Rust(runebender). Because there is no good UI library in Rust,
| and there's good reason to think Rust is a good fit for this, you
| want to build your own (Druid). So far so good. But, now you are
| also trying to build your own 2D renderer and not a basic one:
| you want to advance the state of the art in that field too.
|
| Not that I'm not exited, because if all this lands, it will be
| super great for the Rust ecosystem, but sometimes because you're
| so deep in the rabbit hole, I'm afraid you get burned-out (or
| bored) and that everything would be lost because nothing would be
| polished enough to be usable at that point.
|
| Is that a risk you're taking on purpose? Or is it just that you
| have a plan to avoid it?
|
| Thanks in advance.
| fhars wrote:
| On the other hand, looking at Raph's previous activities, I
| wouldn't be too surprised if all those other things you
| describe are just project management kung-fu to put him in a
| position where he just hast to continue to do research that
| advances the state of 2D rendering.
| chrismorgan wrote:
| One thing that Raph is exceptionally good at is building a
| community around these sorts of things, and guiding it in the
| right direction. None of these things are being built by Raph
| alone, though he's definitely still a primary worker in a lot
| of them.
| pavlov wrote:
| I'm not someone of Raph's caliber, but this reminds me of my
| own career rabbit hole.
|
| In 2002 I was a film student with a "new media" side job
| (that's what they used to call web/Flash development). I had
| cleared my schedule for six months so I could work on an
| ambitious animation project mixing 2D and 3D. As I got started,
| I figured I'd need to write some scripts for a 3D application I
| was using (Softimage). Looking deeper, I came to the conclusion
| my needs were complex enough that I should write a small
| separate application rather than scripts. Then I realized my
| application would need a little compositing engine to mirror
| what existed in Softimage. To make that work fast enough, I
| needed to learn about GPU shaders (brand new at the era). Also
| I needed to learn about YUV pixel formats and media
| containers...
|
| Flash forward 18 years, I'm still at the bottom of this rabbit
| hole, sometimes halfheartedly looking for the door to go back
| up but just finding more glimpses into weirder wonderlands. I
| wrote another YUV compositor just a couple of months ago, but
| haven't made a serious attempt at animation in probably 15
| years.
|
| I wonder if other people have this kind of experience, and
| whether there's some kind of law of "tech stack career gravity"
| in evidence here. When you become expert in something lower
| level, it increases the "career delta-v" to move back up.
| [deleted]
| raphlinus wrote:
| This is a good question, and I'm well aware of the broad scope
| of my projects, especially spanning low to high level.
|
| A few things might help put this in context. First, Druid well
| predated Runebender, though Runebender is now the "hero app"
| (before, it was xi-editor, now on the back burner).
|
| Second, I have a _lot_ of experience doing high performance 2D
| and font rendering, from libart to working on the PDF 1.4 blend
| modes in Ghostscript to font-rs. I 've also been curious about
| GPU for a while, not least because that was what was actually
| painting the text on Android, and I worked on the Android UI
| team for almost 5 years. So now that GPU compute is becoming
| mainstream, I see an almost unique opportunity to apply my
| skills there.
|
| Third, I'm not doing all this by myself. I'm deliberately
| trying to cultivate open source community involvement and,
| really, building a team, though it has diffuse borders. Now is
| also a good time to acknowledge my long-time collaboration with
| Colin Rofls, who does a huge amount of the day to day work on
| both Runebender and Druid.
|
| Lastly, I published this in advance of a career move, which is
| becoming a research software engineer on the Google Fonts team.
| I believe this is a perfect position for me to continue pushing
| this research agenda forward, and I'm hoping will bring more
| resources and focus.
|
| There is no chance of me getting bored doing this. Burnout is
| something I'm watching carefully, as I have experienced it (it
| was the end of my time on Android), but one thing I discovered
| in my 2.5 years away from being a full-timer at Google is that
| graphics research is what I love the most, and would probably
| be doing even if it wasn't also a good career move.
| jancsika wrote:
| > a lot of experience doing high performance 2D
|
| Is there a good ELI5 about the current state of 2D GPU
| acceleration?
| raphlinus wrote:
| As I posted to a similar request, this is an arcane field,
| and different things are meant by 2D - in games, it's
| largely painting sprites from sprite sheets, I think of it
| as involving vector graphics, and there are other contexts.
|
| I think a good blog post that motivates some of the main
| differences between 2D and 3D in the GPU context is this
| one: https://blog.mecheye.net/2019/05/why-is-2d-graphics-
| is-harde...
| anchpop wrote:
| I think Rust and Haskell, due to their irrelevance in industry
| and general "nerdiness", attract a certain type of hacker.
| Specifically I've noticed that there are some libraries for both
| languages that are just _so_ good that they make you never want
| to use anything else. One example in Haskell is Megaparsec [0],
| by far the best point in the parser framework design-space I 'm
| aware of. An example in Rust is wgpu-rs, which maybe isn't "all
| the way there" yet but is already turning into a very ergonomic
| low-level rendering API. Although I haven't used them, I think
| piet-gpu and pathfinder may be in this category also. I don't
| have a link handy but I remember seeing a tweet from the
| developer of Pathfinder where he was reverse-engineering MacOS's
| idiosyncratic font rendering so he could generate identical-
| looking output as the native renderer. That's going above-and-
| beyond what any reasonable library developer would do and I love
| it.
|
| I'm not saying there aren't any great libraries for other
| languages (there certainly are, like Halide for C++) but that I'm
| more often pleasantly surprised by the library quality in Haskell
| and Rust than I am in other languages (when there are libraries
| available, anyway).
|
| [0]: https://hackage.haskell.org/package/megaparsec
|
| [1]: https://github.com/gfx-rs/wgpu-rs
| nicoburns wrote:
| I'm not sure you can really characterise Rust as irrelevant to
| industry anymore (with some of the most widely used software
| written in Rust and FAANG companies hiring core developers),
| but I do agree that it has an unusually high quality standard
| for libraries (I'm unfamiliar with the Haskell ecosystem but I
| hear good things).
|
| However, I think that while some of it is certainly cultural, a
| lot of it is due to the type systems in these languages being a
| lot more powerful which allows for more expressive APIs and
| more robust error handling, etc.
| kvark wrote:
| Wgpu-rs is also going down the rabbit hole of re-inventing the
| world: in addition to implementing WebGPU and targeting all the
| GPU APIs that are available, we are also trying to do all the
| shader translation ourselves now (project Naga). I hope to not
| be burned by this.
|
| Pathfinder future is unclear. It's not ready to be integrated
| into WebRender yet, and Patrick no longer works for Mozilla. I
| see no activity on their projects. Would appreciate if they
| show up here and clarity.
| adamnemecek wrote:
| Rust is gaining traction like nothing else.
| neolog wrote:
| What is an introduction to the basic concepts and terminology
| being discussed here?
|
| (I write software but nothing GPU- or graphics-related.)
| raphlinus wrote:
| Unfortunately, both 2D graphics and the programming of Vulkan
| compute shaders are very arcane topics, and the intersection of
| the two basically maxes out.
|
| For GPU programming, I have a list of resources here:
| https://raphlinus.github.io/gpu/2020/02/12/gpu-
| resources.htm..., and also a talk here:
| https://www.janestreet.com/tech-talks/a-taste-of-gpu-compute...
|
| Re 2D graphics, a long term ambition of mine is to write a book
| on the topic (and I have a repo started with a rough, bullet
| point outline), largely because I don't know of any source that
| brings the concepts together. I don't think I'll be able to
| spend significant time on it, though, as I have my hands pretty
| full. I am hoping to do more explaining and public
| communication as part of my piet-gpu work.
|
| A good snapshot of GPU font rendering work from 3 years ago is:
| https://aras-p.info/blog/2017/02/15/Font-Rendering-is-Gettin...
| . The linked papers are quite good and have informed my
| thinking, though of course I hope to advance the state of the
| art even further.
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