From 9f04586bc0bb778b84d92a1b160f973466aa6a3d Mon Sep 17 00:00:00 2001 From: tinko92 Date: Sun, 27 Oct 2024 09:10:31 +0800 Subject: [PATCH] Use an error bound filter instead of long double in isInCircle predicate. --- .../quadedge/TrianglePredicate.cpp | 66 +++++++++++++++---- 1 file changed, 53 insertions(+), 13 deletions(-) diff --git a/src/triangulate/quadedge/TrianglePredicate.cpp b/src/triangulate/quadedge/TrianglePredicate.cpp index 09a606e874..bd7dba2606 100644 --- a/src/triangulate/quadedge/TrianglePredicate.cpp +++ b/src/triangulate/quadedge/TrianglePredicate.cpp @@ -29,16 +29,30 @@ namespace quadedge { geom::Location TrianglePredicate::isInCircleNonRobust( - const CoordinateXY& a, const CoordinateXY& b, const CoordinateXY& c, - const CoordinateXY& p) + const CoordinateXY& p, const CoordinateXY& q, const CoordinateXY& r, + const CoordinateXY& t) { - auto det = - (a.x * a.x + a.y * a.y) * triArea(b, c, p) - - (b.x * b.x + b.y * b.y) * triArea(a, c, p) - + (c.x * c.x + c.y * c.y) * triArea(a, b, p) - - (p.x * p.x + p.y * p.y) * triArea(a, b, c); - - return det > 0 ? geom::Location::EXTERIOR : (det < 0 ? geom::Location::INTERIOR : geom::Location::BOUNDARY); + auto qpx = q.x - p.x; + auto qpy = q.y - p.y; + auto rpx = r.x - p.x; + auto rpy = r.y - p.y; + auto tpx = t.x - p.x; + auto tpy = t.y - p.y; + auto tqx = t.x - q.x; + auto tqy = t.y - q.y; + auto rqx = r.x - q.x; + auto rqy = r.y - q.y; + auto qpxtpy = qpx * tpy; + auto qpytpx = qpy * tpx; + auto tpxtqx = tpx * tqx; + auto tpytqy = tpy * tqy; + auto qpxrpy = qpx * rpy; + auto qpyrpx = qpy * rpx; + auto rpxrqx = rpx * rqx; + auto rpyrqy = rpy * rqy; + auto det = (qpxtpy - qpytpx) * (rpxrqx + rpyrqy) + - (qpxrpy - qpyrpx) * (tpxtqx + tpytqy); + return static_cast( (det > 0) - (det < 0) + 1 ); } geom::Location @@ -91,11 +105,37 @@ TrianglePredicate::triArea(const CoordinateXY& a, geom::Location TrianglePredicate::isInCircleRobust( - const CoordinateXY& a, const CoordinateXY& b, const CoordinateXY& c, - const CoordinateXY& p) + const CoordinateXY& q, const CoordinateXY& p, const CoordinateXY& r, + const CoordinateXY& t) { - // This implementation is not robust, name is ported from JTS. - return isInCircleNormalized(a, b, c, p); + // This implementation is not robust and defaults to BOUNDARY in case of + // uncertainty. + auto qpx = q.x - p.x; + auto qpy = q.y - p.y; + auto rpx = r.x - p.x; + auto rpy = r.y - p.y; + auto tpx = t.x - p.x; + auto tpy = t.y - p.y; + auto tqx = t.x - q.x; + auto tqy = t.y - q.y; + auto rqx = r.x - q.x; + auto rqy = r.y - q.y; + auto qpxtpy = qpx * tpy; + auto qpytpx = qpy * tpx; + auto tpxtqx = tpx * tqx; + auto tpytqy = tpy * tqy; + auto qpxrpy = qpx * rpy; + auto qpyrpx = qpy * rpx; + auto rpxrqx = rpx * rqx; + auto rpyrqy = rpy * rqy; + auto det = (qpxtpy - qpytpx) * (rpxrqx + rpyrqy) + - (qpxrpy - qpyrpx) * (tpxtqx + tpytqy); + auto deterror = ((std::abs(qpxtpy) + std::abs(qpytpx)) + * (std::abs(rpxrqx) + std::abs(rpyrqy)) + + (std::abs(qpxrpy) + std::abs(qpyrpx)) + * (std::abs(tpxtqx) + std::abs(tpytqy))) + * 9.99200719823023e-16; + return static_cast( (det > deterror) - (det < -deterror) + 1 ); } } // namespace geos.triangulate.quadedge