)]}'
{
  "commit": "b24903553e3437e53783ef146fdebba494958b55",
  "tree": "1a6cb9e0f93baf0ad15bd7676d71f9cffa98bd08",
  "parents": [
    "809244764436824f20426bd53f92e645e9845ab3"
  ],
  "author": {
    "name": "Thomas Smith",
    "email": "68340554+b0nes164@users.noreply.github.com",
    "time": "Mon Dec 08 16:06:53 2025 -0500"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Mon Dec 08 21:06:53 2025 +0000"
  },
  "message": "Add tile intersection checking (#1293)\n\nThis PR adds generation of intersection data to `make_tiles.` \n\nFor our MSAA calculations, we need the points where a line intersects\nwith a tile. Since the end goal is to perform the MSAA in parallel, we\nneed these intersections to be watertight between different threads. By\nperforming these calculations in `make_tiles`, we can create a source of\nground truth, ensuring watertightness.\n\nAlthough it is feasible to calculate the exact intersection points in\n`make_tiles`, we defer that work to the gpu. Instead we create an\nintersection bitmask, which unambiguously defines which edges the line\nintersects. We say a line *intersects* the edge of a tile if it touches\nthat edge AND continues into another tile. A endpoint that exactly\ntouches an edge does NOT count as intersecting, though it may still\ncontribute to winding (in the case of a top edge touch).\n\nThe bitmask is 5 bits, and will be consumed downstream by the\nrasterization stage:\n`P(erfect) | R(ight) | L(eft) | B(ottom) | T(op)`\nThe lower 4 bits correspond to the intersection edges. The \"Perfect\" bit\nis necessary to resolve ambiguity in cases where a line perfectly\nintersects with a corner of a tile.\n\n---\nCases of 3 bit ambiguity can be resolved by always calculating\nintersections on the opposing edges of the tile.\nConsider a tile with intersections `T | L | B`:\n```\no--------+\n|\\       |\n| \\      |\n|  \\     | \n+---o----+\n```\nCalculate the intersections on `T` and `B`!\n\n---\n\nCases of 2 bit ambiguity require the \"Perfect\" bit, which is set when\nthere is exactly one unique edge intersection.\nConsider a tile with intersections `T | L`:\n\nThis is valid:\n```\no--------+\n|\\       |\n| o      |\n|        | \n+--------+\n```\n\nBut so is this:\n ```\n+--o-----+\n| /      |\no        |\n|        | \n+--------+\n```\n\nWith the perfect bit, the first case would be `P | T | L` and the second case would be `T | L`\n\n---------\n\nCo-authored-by: Thomas Smith \u003cthomsmit@google.com\u003e",
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