Implement intersection

crates/bermuda/tests/intersection.rs

@@ -0,0 +1,217 @@
+use rstest::rstest;
+use std::collections::HashSet;
+use triangulation::intersection;
+use triangulation::point::{Point, Segment};
+
+fn seg(x1: i32, y1: i32, x2: i32, y2: i32) -> Segment {
+    Segment::new(
+        Point::new(x1 as f32, y1 as f32),
+        Point::new(x2 as f32, y2 as f32),
+    )
+}
+
+fn seg_f(x1: f32, y1: f32, x2: f32, y2: f32) -> Segment {
+    Segment::new(Point::new(x1, y1), Point::new(x2, y2))
+}
+
+#[rstest]
+#[case(seg(0, 0, 2, 2), Point::new(1.0, 1.0), true)]
+#[case(seg(0, 0, 0, 2), Point::new(0.0, 1.0), true)]
+#[case(seg(0, 0, 2, 0), Point::new(1.0, 0.0), true)]
+#[case(seg(0, 0, 1, 1), Point::new(2.0, 2.0), false)]
+#[case(seg(0, 0, 0, 1), Point::new(0.0, 2.0), false)]
+#[case(seg(0, 0, 1, 0), Point::new(2.0, 0.0), false)]
+#[case(seg_f(1e6, 1e6, 3e6, 3e6), Point::new(2e6, 2e6), true)]
+#[case(seg_f(0.0, 0.0, 0.0001, 0.0001), Point::new(0.00005, 0.00005), true)]
+#[case(seg(0, 0, -2, -2), Point::new(-1.0, -1.0), true)]
+fn test_on_segment_if_collinear(#[case] s: Segment, #[case] q: Point, #[case] expected: bool) {
+    assert_eq!(intersection::on_segment_if_collinear(&s, q), expected);
+}
+
+#[rstest]
+fn test_do_intersect_crossing_segments() {
+    assert!(intersection::do_intersect(
+        &Segment::new(Point::new_i(0, -1), Point::new_i(0, 1)),
+        &Segment::new(Point::new_i(-1, 0), Point::new_i(1, 0))
+    ));
+}
+
+#[rstest]
+#[case(Segment::new_i((0, 0), (1, 1)), Segment::new_i((1, 0), (0, 1)))]
+#[case(Segment::new_i((1, 0), (0, 1)), Segment::new_i((0, 0), (1, 1)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_i((0, 1), (1, 1)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_i((1, 1), (0, 1)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_i((0, 0), (1, 1)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_i((1, 1), (0, 0)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_f((0.0, 0.5), (1.0, 1.0)))]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_f((1.0, 1.0), (0.0, 0.5)))]
+fn test_do_intersect(#[case] s1: Segment, #[case] s2: Segment) {
+    assert!(intersection::do_intersect(&s1, &s2));
+}
+
+#[rstest]
+#[case(Segment::new_i((0, 0), (0, 1)), Segment::new_i((1, 2), (-1, 2)))]
+#[case(Segment::new_i((0, 0), (1, 0)), Segment::new_i((2, 1), (2, -1)))]
+#[case(Segment::new_i((0, 0), (1, 1)), Segment::new_i((1, 2), (0, 1)))]
+fn test_do_intersect_ne(#[case] s1: Segment, #[case] s2: Segment) {
+    assert!(!intersection::do_intersect(&s1, &s2));
+}
+
+#[rstest]
+fn test_do_intersect_parallel_segments() {
+    assert_ne!(
+        intersection::do_intersect(
+            &Segment::new(Point::new_i(0, -1), Point::new_i(0, 1)),
+            &Segment::new(Point::new_i(1, -2), Point::new_i(1, 1))
+        ),
+        true
+    )
+}
+
+#[rstest]
+#[case(Segment::new_i((0, 0), (2, 2)), Segment::new_i((2, 0), (0, 2)), Point::new_i(1, 1))]
+#[case(Segment::new_i((0, 0), (1, 0)), Segment::new_i((0, 1), (0, 0)), Point::new_i(0, 0))]
+#[case(Segment::new_i((0, 0), (2, 0)), Segment::new_i((1, 0), (1, 2)), Point::new_i(1, 0))]
+#[case(Segment::new_f((0.0, 0.0), (2.0, 2.0)), Segment::new_f((2.0, 0.0), (0.0, 2.0)), Point::new(1.0, 1.0))]
+#[case(Segment::new_f((0.0, 0.0), (1.0, 1.0)), Segment::new_f((0.99, 0.0), (0.0, 0.99)), Point::new(0.495, 0.495))]
+#[case(Segment::new_f((1e6, 1e6), (2e6, 2e6)), Segment::new_f((2e6, 1e6), (1e6, 2e6)), Point::new(1.5e6, 1.5e6))]
+fn test_find_intersection_point(#[case] s1: Segment, #[case] s2: Segment, #[case] expected: Point) {
+    assert_eq!(
+        intersection::find_intersection(&s1, &s2),
+        intersection::Intersection::PointIntersection(expected)
+    );
+    assert_eq!(
+        intersection::find_intersection(&s2, &s1),
+        intersection::Intersection::PointIntersection(expected)
+    );
+}
+
+#[rstest]
+fn test_find_intersection_collinear_segments() {
+    assert_eq!(
+        intersection::find_intersection(
+            &Segment::new_i((0, 0), (2, 0)),
+            &Segment::new_i((1, 0), (3, 0))
+        ),
+        intersection::Intersection::CollinearWithOverlap(vec![
+            Point::new_i(1, 0),
+            Point::new_i(2, 0)
+        ])
+    );
+    assert_eq!(
+        intersection::find_intersection(
+            &Segment::new_i((0, 0), (2, 0)),
+            &Segment::new_i((1, 0), (3, 0))
+        ),
+        intersection::Intersection::CollinearWithOverlap(vec![
+            Point::new_i(1, 0),
+            Point::new_i(2, 0)
+        ])
+    );
+}
+
+/// Tests a simple square configuration with no intersections.
+/// Each segment connects to the next at endpoints, but there
+/// are no true intersections between non-adjacent segments.
+///  (1, 0) --- (1, 1)
+///   |           |
+/// (0, 0) --- (0, 1)
+#[rstest]
+fn test_find_intersections_1() {
+    let segments = vec![
+        Segment::new(Point::new(0.0, 0.0), Point::new(0.0, 1.0)),
+        Segment::new(Point::new(0.0, 1.0), Point::new(1.0, 1.0)),
+        Segment::new(Point::new(1.0, 1.0), Point::new(1.0, 0.0)),
+        Segment::new(Point::new(1.0, 0.0), Point::new(0.0, 0.0)),
+    ];
+    let intersections = intersection::find_intersections(&segments);
+    assert!(intersections.is_empty());
+}
+
+/// Tests a configuration with two intersecting diagonals.
+/// Expected behavior:
+/// - Only one intersection is recorded between segments 1 and 3
+/// - The intersection occurs at (0.5, 0.5)
+///     (1, 0) --- (1, 1)
+///         \     /
+///          \   /
+///           \ /
+///            X
+///           / \
+///          /   \
+///         /     \
+///     (0, 0) --- (0, 1)
+#[rstest]
+fn test_find_intersections_2() {
+    let segments = vec![
+        Segment::new(Point::new(0.0, 0.0), Point::new(0.0, 1.0)),
+        Segment::new(Point::new(0.0, 1.0), Point::new(1.0, 0.0)),
+        Segment::new(Point::new(1.0, 0.0), Point::new(1.0, 1.0)),
+        Segment::new(Point::new(1.0, 1.0), Point::new(0.0, 0.0)),
+        Segment::new(Point::new(0.0, 0.0), Point::new(0.0, 1.0)),
+    ];
+    let intersections = intersection::find_intersections(&segments);
+    let expected = [(1, 3)]
+        .iter()
+        .map(|&(a, b)| intersection::OrderedPair::new(a, b))
+        .collect();
+    assert_eq!(intersections, expected);
+}
+
+#[rstest]
+#[case::no_intersections_simple_square(
+    vec![
+        Segment::new_i((0, 0), (0, 1)),
+        Segment::new_i((0, 1), (1, 1)),
+        Segment::new_i((1, 1), (1, 0)),
+        Segment::new_i((1, 0), (0, 0)),
+    ],
+    HashSet::new()
+)]
+#[case::one_intersection_crossing_diagonals(
+    vec![
+        Segment::new_i((0, 0), (2, 2)),
+        Segment::new_i((2, 0), (0, 2)),
+    ],
+    [(0, 1)].iter().map(|&(a, b)| intersection::OrderedPair::new(a, b)).collect()
+)]
+#[case::multiple_intersections_complex_shape(
+    vec![
+        Segment::new_i((0, 0), (2, 2)),
+        Segment::new_i((2, 0), (0, 2)),
+        Segment::new_i((1, 0), (1, 2)),
+        Segment::new_i((0, 1), (2, 1)),
+    ],
+    [(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)].iter().map(|&(a, b)| intersection::OrderedPair::new(a, b)).collect()
+)]
+#[case::no_intersections_non_intersecting_lines(
+    vec![
+        Segment::new_i((0, 0), (1, 1)),
+        Segment::new_i((2, 2), (3, 3)),
+    ],
+    HashSet::new()
+)]
+#[case::one_intersection_t_shaped_intersection(
+    vec![
+        Segment::new_i((0, 0), (2, 0)),
+        Segment::new_i((1, -1), (1, 1)),
+    ],
+    [(0, 1)].iter().map(|&(a, b)| intersection::OrderedPair::new(a, b)).collect()
+)]
+#[case::multiple_intersections_grid_shape(
+    vec![
+        Segment::new_i((0, 0), (2, 0)),
+        Segment::new_i((0, 1), (2, 1)),
+        Segment::new_i((0, 2), (2, 2)),
+        Segment::new_i((0, 0), (0, 2)),
+        Segment::new_i((1, 0), (1, 2)),
+        Segment::new_i((2, 0), (2, 2)),
+    ],
+    [(0, 4), (1, 3), (1, 4), (1, 5), (2, 4)].iter().map(|&(a, b)| intersection::OrderedPair::new(a, b)).collect()
+)]
+fn test_find_intersections_param(
+    #[case] segments: Vec<Segment>,
+    #[case] expected: HashSet<intersection::OrderedPair>,
+) {
+    assert_eq!(intersection::find_intersections(&segments), expected);
+}