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Author uses a lot of odd, confusing terminology and brings CPU baggage to the GPU creating the worst of both worlds. Shader hacks and CPU-bound partitioning and

Author uses a lot of odd, confusing terminology and brings CPU baggage to the GPU creating the worst of both worlds. Shader hacks and CPU-bound partitioning and choosing the Greek letter alpha to be your accumulator in a graphics article? Oh my. NV_path_rendering solved this in 2011. https://developer.nvidia.com/nv-path-rendering https://developer.nvidia.com/nv-path-rendering It never became a standard but was a compile-time option in Skia for a long time. Skia of course solved this the right way. https://skia.org/ https://skia.org/

bsder 9mo ago
While the author doesn't seem to be aware of state of the art in the field, vector rendering is absolute NOT a solved problem whether on CPU or GPU. Vello by Raph Levien seems to be a nice combination of what is required to pull this off on GPUs. https://www.youtube.com/watch?v=_sv8K190Zps https://www.youtube.com/watch?v=_sv8K190Zps
- lukan 9mo ago
  Yeah, I have high hopes for Vello to take off. I could throw away lots of hacks and caching and whatnot if I could do fast vector rendering reliable on the GPU. I think Rive also does vector rendering on the GPU https://rive.app/renderer https://rive.app/renderer But it is not really meant (yet?) as a general graphics libary, but just a renderer for the rive design tools.
  - pier25 9mo ago
    AFAIK you can use the Rive renderer in your C++ app. http://github.com/rive-app/rive-runtime http://github.com/rive-app/rive-runtime
- bean469 9mo ago
  > While the author doesn't seem to be aware of state of the art in the field The blog post is from 2022, though
sirwhinesalot 9mo ago
So what is the right way that Skia uses? Why is there still discussion on how to do vector graphics on the GPU right if Skia's approach is good enough? Not being sarcastic, genuinely curious.
- cyberax 9mo ago
  The major unsolved problem is real-time high-quality text rendering on GPU. Skia just renders fonts on the CPU with all kinds of hacks ( https://skia.org/docs/dev/design/raster_tragedy/ https://skia.org/docs/dev/design/raster_tragedy/ ). It then renders them as textures. Ideally, we want to have as much stuff rendered on the GPU as possible. Ideally with support for glyph layout. This is not at all trivial, especially for complex languages like Devanagari. In the perfect world, we want to be able to create a 3D cube and just have the renderer put the text on one of its facets. And have it rendered perfectly as you rotate the cube.
deleted 9mo ago
[deleted]
exDM69 9mo ago
> NV_path_rendering solved this in 2011. By no means is this a solved problem. NV_path_rendering is an implementation of "stencil then cover" method with a lot of CPU preprocessing. It's also only available on OpenGL, not on any other graphics API. The STC method scales very badly with increasing resolutions as it is using a lot of fill rate and memory bandwidth. It's mostly using GPU fixed function units (rasterizer and stencil test), leaving the "shader cores" practically idle. There's a lot of room for improvement to get more performance and better GPU utilization.
Asm2D 9mo ago
You know nothing. Skia is definitely not a good example at all. Skia started as a CPU renderer, and added GPU rendering later, which heavily relies on caching. Vello, for example, takes a completely different approach compared to Skia. NV path rendering is a joke. nVidia though that ALL graphics would be rendered on GPU within 2 years after making the presentation, and it took 2 decades and 2D CPU renderers still shine.
- nicoburns 9mo ago
  I believe Skia's new Graphite architecture is much more similar to Vello
  - badlibrarian 9mo ago
    Right. The question is does Skia grows its broad and useful toolkit with an eye toward further GPU optimization? Or does Vello (broadened and perhaps burdened by Rust and the shader-obsessive crowd) grow a broad and useful API? There's also the issue of just how many billions of line segments you really need to draw every 1/120th of a second at 8K resolution, but I'll leave those discussions to dark-gray Discord forums rendered by Skia in a browser.
    - coffeeaddict1 9mo ago
      > There's also the issue of just how many billions of line segments you really need to draw every 1/120th of a second at 8K resolution IMO, one of biggest benefit of a high performance renderer would be power savings (very important for laptops and phones). If I can run the same work but use half the power, then by all means I'd be happy to deal with the complications that the GPU brings. AFAIK though, no one really cares about that and even efforts like Vello are just targeting fps gains, which do correlate with reduced power consumption but only indirectly.
      - badlibrarian 9mo ago
        It's an argument you can make in any performance effort. But I think the "let's save power using GPUs" ship sailed even before Microsoft started buying nuclear reactors to power them.

bsder 9mo ago

While the author doesn't seem to be aware of state of the art in the field, vector rendering is absolute NOT a solved problem whether on CPU or GPU. Vello by Raph Levien seems to be a nice combination of what is required to pull this off on GPUs. https://www.youtube.com/watch?v=_sv8K190Zps https://www.youtube.com/watch?v=_sv8K190Zps

lukan 9mo ago
Yeah, I have high hopes for Vello to take off. I could throw away lots of hacks and caching and whatnot if I could do fast vector rendering reliable on the GPU. I think Rive also does vector rendering on the GPU https://rive.app/renderer https://rive.app/renderer But it is not really meant (yet?) as a general graphics libary, but just a renderer for the rive design tools.
- pier25 9mo ago
  AFAIK you can use the Rive renderer in your C++ app. http://github.com/rive-app/rive-runtime http://github.com/rive-app/rive-runtime
bean469 9mo ago
> While the author doesn't seem to be aware of state of the art in the field The blog post is from 2022, though

sirwhinesalot 9mo ago

So what is the right way that Skia uses? Why is there still discussion on how to do vector graphics on the GPU right if Skia's approach is good enough? Not being sarcastic, genuinely curious.

cyberax 9mo ago
The major unsolved problem is real-time high-quality text rendering on GPU. Skia just renders fonts on the CPU with all kinds of hacks ( https://skia.org/docs/dev/design/raster_tragedy/ https://skia.org/docs/dev/design/raster_tragedy/ ). It then renders them as textures. Ideally, we want to have as much stuff rendered on the GPU as possible. Ideally with support for glyph layout. This is not at all trivial, especially for complex languages like Devanagari. In the perfect world, we want to be able to create a 3D cube and just have the renderer put the text on one of its facets. And have it rendered perfectly as you rotate the cube.

deleted 9mo ago

[deleted]

exDM69 9mo ago

> NV_path_rendering solved this in 2011. By no means is this a solved problem. NV_path_rendering is an implementation of "stencil then cover" method with a lot of CPU preprocessing. It's also only available on OpenGL, not on any other graphics API. The STC method scales very badly with increasing resolutions as it is using a lot of fill rate and memory bandwidth. It's mostly using GPU fixed function units (rasterizer and stencil test), leaving the "shader cores" practically idle. There's a lot of room for improvement to get more performance and better GPU utilization.

Asm2D 9mo ago

You know nothing. Skia is definitely not a good example at all. Skia started as a CPU renderer, and added GPU rendering later, which heavily relies on caching. Vello, for example, takes a completely different approach compared to Skia. NV path rendering is a joke. nVidia though that ALL graphics would be rendered on GPU within 2 years after making the presentation, and it took 2 decades and 2D CPU renderers still shine.

nicoburns 9mo ago
I believe Skia's new Graphite architecture is much more similar to Vello
- badlibrarian 9mo ago
  Right. The question is does Skia grows its broad and useful toolkit with an eye toward further GPU optimization? Or does Vello (broadened and perhaps burdened by Rust and the shader-obsessive crowd) grow a broad and useful API? There's also the issue of just how many billions of line segments you really need to draw every 1/120th of a second at 8K resolution, but I'll leave those discussions to dark-gray Discord forums rendered by Skia in a browser.
  - coffeeaddict1 9mo ago
    > There's also the issue of just how many billions of line segments you really need to draw every 1/120th of a second at 8K resolution IMO, one of biggest benefit of a high performance renderer would be power savings (very important for laptops and phones). If I can run the same work but use half the power, then by all means I'd be happy to deal with the complications that the GPU brings. AFAIK though, no one really cares about that and even efforts like Vello are just targeting fps gains, which do correlate with reduced power consumption but only indirectly.
    - badlibrarian 9mo ago
      It's an argument you can make in any performance effort. But I think the "let's save power using GPUs" ship sailed even before Microsoft started buying nuclear reactors to power them.