3 files changed, 79 insertions, 20 deletions

diff --git a/src/math/mod.rs b/src/math/mod.rs
index 6f83c98..b84d270 100644
--- a/src/math/mod.rs
+++ b/src/math/mod.rs
@@ -20,6 +20,12 @@ pub trait Surface<T: Scalar + Copy> {
 
     /// Checks if a line segment is entirely contained by this surface.
     fn contains_line_segment(&self, line_segment: &LineSegment<T>) -> bool;
+
+    /// Checks if a rectangle is entirely contained inside this surface.
+    fn contains_rect(&self, rect: &Rect<T>) -> bool;
+
+    /// Checks if a polygon is contained wholly by this surface.
+    fn contains_polygon(&self, polygon: &Polygon<T>) -> bool;
 }
 
 /// Round a floating point number to the nearest step given by the step argument. For instance, if
diff --git a/src/math/polygon/mod.rs b/src/math/polygon/mod.rs
index ed48751..c9dad91 100644
--- a/src/math/polygon/mod.rs
+++ b/src/math/polygon/mod.rs
@@ -6,7 +6,7 @@ pub mod triangulate;
 pub use polygon_graph::*;
 pub use triangulate::*;
 
-use super::{LineSegment, Surface, TripletOrientation, Vec2};
+use super::{LineSegment, Rect, Surface, TripletOrientation, Vec2};
 use crate::math;
 use nalgebra::{ClosedDiv, ClosedMul, ClosedSub, RealField, Scalar};
 use num_traits::Zero;
@@ -361,6 +361,54 @@ impl<
 
         true
     }
+
+    fn contains_rect(&self, rect: &Rect<T>) -> bool {
+        /* Turn the rectangle into a vector with its hull line segments. If all hull segments are
+         * contained in the polygon, the rectangle is contained completely.
+         */
+        let hull_edges = [
+            // Top left to bottom left.
+            LineSegment::new(
+                Vec2::new(rect.x, rect.y),
+                Vec2::new(rect.x, rect.y + rect.h),
+            ),
+            // Bottom left to bottom right.
+            LineSegment::new(
+                Vec2::new(rect.x, rect.y + rect.h),
+                Vec2::new(rect.x + rect.w, rect.y + rect.h),
+            ),
+            // Bottom right to top right.
+            LineSegment::new(
+                Vec2::new(rect.x + rect.w, rect.y + rect.h),
+                Vec2::new(rect.x + rect.w, rect.y),
+            ),
+            // Top right to top left.
+            LineSegment::new(
+                Vec2::new(rect.x + rect.w, rect.y),
+                Vec2::new(rect.x, rect.y),
+            ),
+        ];
+
+        hull_edges
+            .iter()
+            .all(|edge| self.contains_line_segment(edge))
+    }
+
+    fn contains_polygon(&self, polygon: &Polygon<T>) -> bool {
+        /* Check for all edges of the polygon that they are contained by the polygon. If they all
+         * are, then the polygon itself must also be contained.
+         */
+        for i in 0..polygon.corners.len() {
+            let next = (i + 1) % polygon.corners.len();
+            if !self
+                .contains_line_segment(&LineSegment::new(polygon.corners[i], polygon.corners[next]))
+            {
+                return false;
+            }
+        }
+
+        true
+    }
 }
 
 /* Helper function to calculate the combined angle of a set of points when connecting them one
diff --git a/src/math/rect.rs b/src/math/rect.rs
index 876e728..5f4e5f5 100644
--- a/src/math/rect.rs
+++ b/src/math/rect.rs
@@ -1,9 +1,9 @@
-use super::{LineSegment, Surface, Vec2};
+use super::{LineSegment, Polygon, Surface, Vec2};
 //use alga::general::{Additive, Identity};
-use nalgebra::{ClosedAdd, RealField, Scalar};
+use nalgebra::{ClosedAdd, ClosedSub, RealField, Scalar};
 use num_traits::identities::Zero;
 use serde::{Deserialize, Serialize};
-use std::ops::{Add, AddAssign, Sub};
+use std::ops::{Add, AddAssign};
 
 /// Represents a Rectangle with the value type T.
 #[derive(Copy, Clone, Debug, Default, Serialize, Deserialize)]
@@ -63,21 +63,6 @@ impl<T: Scalar + Copy> Rect<T> {
             || this.y + this.h < other.y)
     }
 
-    /// Returns true if the entire rect is contained inside this rectangle.
-    pub fn contains_rect(&self, rect: Rect<T>) -> bool
-    where
-        T: Add<Output = T> + Sub<Output = T> + PartialOrd + Zero,
-    {
-        /* True, if the rightmost x-coordinate of the called rectangle is further right or the same
-         * as the rightmost coordinate of the given rect.
-         */
-        let x_exceeds = self.x + self.w - rect.x - rect.w >= T::zero();
-        // The same for the y-coordinates
-        let y_exceeds = self.y + self.h - rect.y - rect.h >= T::zero();
-
-        x_exceeds && y_exceeds && self.x <= rect.x && self.y <= rect.y
-    }
-
     /// Function to calculate the bounding rectangle that is between two vectors. The order of the
     /// vectors is irrelevent for this. As long as they are diagonally opposite of each other, this
     /// function will work.
@@ -128,7 +113,7 @@ impl<T: Scalar + Copy> Rect<T> {
     }
 }
 
-impl<T: Scalar + Copy + PartialOrd + ClosedAdd> Surface<T> for Rect<T> {
+impl<T: Scalar + Copy + PartialOrd + ClosedAdd + ClosedSub + Zero> Surface<T> for Rect<T> {
     fn contains_point(&self, point: &Vec2<T>) -> bool {
         point.x >= self.x
             && point.x <= self.x + self.w
@@ -139,6 +124,26 @@ impl<T: Scalar + Copy + PartialOrd + ClosedAdd> Surface<T> for Rect<T> {
     fn contains_line_segment(&self, line_segment: &LineSegment<T>) -> bool {
         self.contains_point(&line_segment.start) && self.contains_point(&line_segment.end)
     }
+
+    fn contains_rect(&self, rect: &Rect<T>) -> bool {
+        /* True, if the rightmost x-coordinate of the called rectangle is further right or the same
+         * as the rightmost coordinate of the given rect.
+         */
+        let x_exceeds = self.x + self.w - rect.x - rect.w >= T::zero();
+        // The same for the y-coordinates
+        let y_exceeds = self.y + self.h - rect.y - rect.h >= T::zero();
+
+        x_exceeds && y_exceeds && self.x <= rect.x && self.y <= rect.y
+    }
+
+    fn contains_polygon(&self, polygon: &Polygon<T>) -> bool {
+        // Check if all vertices of the polygon lie inside the rectangle. If so, the polygon must
+        // be contained in its entirety.
+        polygon
+            .corners()
+            .iter()
+            .all(|&corner| self.contains_point(&corner))
+    }
 }
 
 // This is sad, but also sadly necessary :/