--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/landgen/src/outline.rs	Sun Oct 14 19:04:51 2018 +0200
@@ -0,0 +1,86 @@
+pub struct Point {
+    x: i32,
+    y: i32,
+}
+
+pub struct Outline {
+    points: Vec<Point>,
+}
+
+fn check_intersect(v1: &Point, v2: &Point, v3: &Point, v4: &Point) -> bool {
+    let dm: i32 = (v4.y - v3.y) * (v2.x - v1.x) - (v4.x - v3.x) * (v2.y - v1.y);
+
+    if dm == 0 {
+        return false;
+    }
+
+    let c1: i32 = (v4.x - v3.x) * (v1.y - v3.y) - (v4.y - v3.y) * (v1.x - v3.x);
+
+    if dm > 0 {
+        if (c1 < 0) || (c1 > dm) {
+            return false;
+        }
+    } else {
+        if (c1 > 0) || (c1 < dm) {
+            return false;
+        }
+    }
+
+    let c2: i32 = (v2.x - v3.x) * (v1.y - v3.y) - (v2.y - v3.y) * (v1.x - v3.x);
+
+    if dm > 0 {
+        if (c2 < 0) || (c2 > dm) {
+            return false;
+        }
+    } else {
+        if (c2 > 0) || (c2 < dm) {
+            return false;
+        }
+    }
+
+    true
+}
+
+impl Outline {
+    fn check_intersects_self_at_index(&self, index: usize) -> bool {
+        if index <= 0 || index > self.points.len() {
+            return false;
+        }
+
+        for i in 1..=self.points.len() - 3 {
+            if i <= index - 1 || i >= index + 2 {
+                if i != index - 1 && check_intersect(
+                    &self.points[index],
+                    &self.points[index - 1],
+                    &self.points[i],
+                    &self.points[i - 1],
+                ) {
+                    return true;
+                }
+                if i != index + 2 && check_intersect(
+                    &self.points[index],
+                    &self.points[index + 1],
+                    &self.points[i],
+                    &self.points[i - 1],
+                ) {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
+}
+
+#[cfg(test)]
+#[test]
+fn intersection() {
+    let p1 = Point{x: 0, y: 0};
+    let p2 = Point{x: 0, y: 10};
+    let p3 = Point{x: -5, y: 5};
+    let p4 = Point{x: 5, y: 5};
+    let p5 = Point{x: 5, y: 16};
+
+    assert!(check_intersect(&p1, &p2, &p3, &p4));
+    assert!(!check_intersect(&p1, &p2, &p3, &p5));
+}