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I've been looking into how viable this is as a performant strategy. If you have non-overlapping areas, then contributions to a single pixel can be made independ

I've been looking into how viable this is as a performant strategy. If you have non-overlapping areas, then contributions to a single pixel can be made independently (since it is just the sum of contributions). The usual approach (computing coverage and blending into the color) is more constrained, where the operations need to be done in back-to-front order.

mfabbri77 2y ago
I've been researching this field for 20 years (I'm one of the developers of AmanithVG). Unfortunately, no matter how fast they are made, all the algorithms to analytically decompose areas involve a step to find intersections and therefore sweepline approaches that are difficult to parallelize and therefore must be done in CPU. However, we are working on it for the next AmanithVG rasterizer, so I'm keeping my eyes open for all possible alternatives.
- muyyatin2 2y ago
  I ran across https://dl.acm.org/doi/pdf/10.1145/72935.72950 https://dl.acm.org/doi/pdf/10.1145/72935.72950 a few weeks ago, it seems like a potential non-sweepline highly-parallel method. I've had some promising results for first doing a higher-dimensional Hilbert-sort (giving spatial locality), and then being able to prune a very large percentage of the quadratic search space. It might still be too slow on the GPU. I'm curious if you have any write-ups on things that have been explored, or if I'd be able to pick your brain some time!
- dvdkon 2y ago
  I believe Vello does this for AA (though I can't find the source now), and it's very fast, running on the GPU via compute shaders.
  - raphlinus 2y ago
    No, Vello does not analytically find intersections. Compositing is (currently) done by alpha blending, which is consistent with the W3C spec but has its own tradeoffs.
- whenc 2y ago
  Here's one to look at: https://dl.acm.org/doi/10.1145/2980179.2982434 https://dl.acm.org/doi/10.1145/2980179.2982434

mfabbri77 2y ago

I've been researching this field for 20 years (I'm one of the developers of AmanithVG). Unfortunately, no matter how fast they are made, all the algorithms to analytically decompose areas involve a step to find intersections and therefore sweepline approaches that are difficult to parallelize and therefore must be done in CPU. However, we are working on it for the next AmanithVG rasterizer, so I'm keeping my eyes open for all possible alternatives.

muyyatin2 2y ago
I ran across https://dl.acm.org/doi/pdf/10.1145/72935.72950 https://dl.acm.org/doi/pdf/10.1145/72935.72950 a few weeks ago, it seems like a potential non-sweepline highly-parallel method. I've had some promising results for first doing a higher-dimensional Hilbert-sort (giving spatial locality), and then being able to prune a very large percentage of the quadratic search space. It might still be too slow on the GPU. I'm curious if you have any write-ups on things that have been explored, or if I'd be able to pick your brain some time!
dvdkon 2y ago
I believe Vello does this for AA (though I can't find the source now), and it's very fast, running on the GPU via compute shaders.
- raphlinus 2y ago
  No, Vello does not analytically find intersections. Compositing is (currently) done by alpha blending, which is consistent with the W3C spec but has its own tradeoffs.
whenc 2y ago
Here's one to look at: https://dl.acm.org/doi/10.1145/2980179.2982434 https://dl.acm.org/doi/10.1145/2980179.2982434