diff --git a/CHANGELOG.md b/CHANGELOG.md index 88bcf97a..4a2264a2 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2,6 +2,11 @@ ## Unreleased +### Modified + +- The `point_in_poly2d` now handles arbitrary (convex and non-convex) polygons. The previous implementation + that only supported convex polygons has been renamed `point_in_convex_poly2d`. + ### Fixed - Fix a crash in `Qbvh::refit` that results from the QBVH tree becoming increasingly imbalanced. diff --git a/src/utils/mod.rs b/src/utils/mod.rs index c6001272..6dbfe227 100644 --- a/src/utils/mod.rs +++ b/src/utils/mod.rs @@ -14,7 +14,7 @@ pub use self::median::median; pub use self::point_cloud_support_point::{ point_cloud_support_point, point_cloud_support_point_id, }; -pub use self::point_in_poly2d::point_in_poly2d; +pub use self::point_in_poly2d::{point_in_convex_poly2d, point_in_poly2d}; pub use self::sdp_matrix::{SdpMatrix2, SdpMatrix3}; pub use self::array::{Array1, Array2, DefaultStorage}; diff --git a/src/utils/point_in_poly2d.rs b/src/utils/point_in_poly2d.rs index b14633d4..aaf19006 100644 --- a/src/utils/point_in_poly2d.rs +++ b/src/utils/point_in_poly2d.rs @@ -2,8 +2,11 @@ use crate::math::Real; use na::Point2; use num::Zero; -/// Tests if the given point is inside of a polygon with arbitrary orientation. -pub fn point_in_poly2d(pt: &Point2, poly: &[Point2]) -> bool { +/// Tests if the given point is inside a convex polygon with arbitrary orientation. +/// +/// The polygon is assumed to be closed, i.e., first and last point of the polygon are implicitly +/// assumed to be connected by an edge. +pub fn point_in_convex_poly2d(pt: &Point2, poly: &[Point2]) -> bool { if poly.is_empty() { false } else { @@ -25,3 +28,108 @@ pub fn point_in_poly2d(pt: &Point2, poly: &[Point2]) -> bool { true } } + +/// Tests if the given point is inside an arbitrary closed polygon with arbitrary orientation, +/// using a counting winding strategy. +/// +/// The polygon is assumed to be closed, i.e., first and last point of the polygon are implicitly +/// assumed to be connected by an edge. +/// +/// This handles concave polygons. For a function dedicated to convex polygons, see [`point_in_convex_poly2d`]. +pub fn point_in_poly2d(pt: &Point2, poly: &[Point2]) -> bool { + if poly.is_empty() { + return false; + } + + let mut winding = 0i32; + + for (i, a) in poly.iter().enumerate() { + let b = poly[(i + 1) % poly.len()]; + let seg_dir = b - a; + let dpt = pt - a; + let perp = dpt.perp(&seg_dir); + winding += match (dpt.y > 0.0, b.y > pt.y) { + (true, true) if perp < 0.0 => 1, + (false, false) if perp > 0.0 => -1, + _ => 0, + }; + } + + winding != 0 +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn point_in_poly2d_concave() { + let poly = [ + [615.4741821289063, 279.4120788574219], + [617.95947265625, 281.8973693847656], + [624.1727294921875, 288.73193359375], + [626.6580200195313, 292.4598693847656], + [634.7352294921875, 302.40106201171875], + [637.8418579101563, 306.7503356933594], + [642.8124389648438, 312.96356201171875], + [652.7536010742188, 330.98193359375], + [654.6176147460938, 334.7098693847656], + [661.4521484375, 349.0003356933594], + [666.4227294921875, 360.18414306640625], + [670.1506958007813, 367.6400451660156], + [675.1212768554688, 381.30914306640625], + [678.2279052734375, 391.2503356933594], + [681.33447265625, 402.43414306640625], + [683.81982421875, 414.23931884765625], + [685.0624389648438, 422.3165283203125], + [685.6837768554688, 431.0150146484375], + [686.3051147460938, 442.8201904296875], + [685.6837768554688, 454.0040283203125], + [683.81982421875, 460.83856201171875], + [679.4705200195313, 470.77972412109375], + [674.4999389648438, 480.720947265625], + [670.1506958007813, 486.93414306640625], + [662.073486328125, 497.49664306640625], + [659.5881958007813, 499.36065673828125], + [653.3749389648438, 503.70989990234375], + [647.7830200195313, 506.1951904296875], + [642.8124389648438, 507.43780517578125], + [631.6286010742188, 508.05914306640625], + [621.0661010742188, 508.05914306640625], + [605.5330200195313, 508.05914306640625], + [596.2131958007813, 508.05914306640625], + [586.893310546875, 508.05914306640625], + [578.8161010742188, 508.05914306640625], + [571.3602294921875, 506.1951904296875], + [559.5551147460938, 499.36065673828125], + [557.0697631835938, 497.49664306640625], + [542.1580200195313, 484.4488525390625], + [534.7021484375, 476.37164306640625], + [532.8381958007813, 473.8863525390625], + [527.2462768554688, 466.43048095703125], + [522.2756958007813, 450.89739990234375], + [521.6543579101563, 444.06280517578125], + [521.0330200195313, 431.6363525390625], + [521.6543579101563, 422.93780517578125], + [523.518310546875, 409.26873779296875], + [527.2462768554688, 397.46356201171875], + [532.8381958007813, 385.6584167480469], + [540.9154052734375, 373.23193359375], + [547.1286010742188, 365.77606201171875], + [559.5551147460938, 354.59222412109375], + [573.2241821289063, 342.165771484375], + [575.70947265625, 339.68048095703125], + [584.4080200195313, 331.603271484375], + [597.455810546875, 317.3128356933594], + [601.8051147460938, 311.7209167480469], + [607.39697265625, 303.6437072753906], + [611.7462768554688, 296.1878356933594], + [614.2315673828125, 288.1106262207031], + [615.4741821289063, 280.65472412109375], + [615.4741821289063, 279.4120788574219], + ] + .map(Point2::from); + let pt = Point2::from([596.0181884765625, 427.9162902832031]); + assert!(point_in_poly2d(&pt, &poly)); + } +}