From da1c3949a449f3fafe579c62ff6b14ffd993a197 Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Sun, 21 Feb 2021 18:01:56 +0100
Subject: Add 3d bounding box and merged SceneIntersection and Intersection

---
 src/core/bound2.rs | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 src/core/bound2.rs

(limited to 'src/core/bound2.rs')

diff --git a/src/core/bound2.rs b/src/core/bound2.rs
new file mode 100644
index 0000000..bc0e7cd
--- /dev/null
+++ b/src/core/bound2.rs
@@ -0,0 +1,127 @@
+//! Implements a 2d axis aligned bounding box
+use crate::{Number, Float};
+use super::vector2::Vector2;
+use crate::core;
+use crate::core::{min, max};
+
+/// Implements a region between min and max
+#[derive(Clone)]
+pub struct Bound2<T: Number> {
+    pub min: Vector2<T>,
+    pub max: Vector2<T>
+}
+
+pub type Bound2i = Bound2<i32>;
+pub type Bound2f = Bound2<Float>;
+
+impl<T: Number> Bound2<T> {
+    /// Creates a new bound from two points
+    ///
+    /// p0 does not have to be smaller than p1
+    pub fn new(p0: &Vector2<T>, p1: &Vector2<T>) -> Self {
+        let min = Vector2::new_xy(min(p0.x, p1.x), min(p0.y, p1.y));
+        let max = Vector2::new_xy(max(p0.x, p1.x), max(p0.y, p1.y));
+
+        Self { min, max }
+    }
+
+    pub fn new_xyxy(x1: T, y1: T, x2: T, y2: T) -> Self {
+        Self::new(
+            &Vector2::new_xy(x1, y1),
+            &Vector2::new_xy(x2, y2),
+            )
+    }
+
+    /// Finds the intersected area between two bounds
+    pub fn intersect(&self, b: &Bound2<T>) -> Bound2<T> {
+        Bound2::new(
+            &Vector2::new_xy(max(self.min.x, b.min.x), max(self.min.y, b.min.y)),
+            &Vector2::new_xy(min(self.max.x, b.max.x), min(self.max.y, b.max.y)),
+            )
+    }
+
+
+    /// Calculates the diagonal vector
+    ///
+    /// Can be used to calculate the size of the bound
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rendering::core::Bound2i;
+    /// let b = Bound2i::new_xyxy(2, 2, 6, 7);
+    /// let diag = b.diagonal();
+    ///
+    /// assert!(diag.x == 4 && diag.y == 5);
+    /// ```
+    pub fn diagonal(&self) -> Vector2<T> {
+        self.max - self.min
+    }
+
+    /// Calculates the area of of the bounded region
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rendering::core::Bound2i;
+    /// let b = Bound2i::new_xyxy(10, 10, 20, 20);
+    /// 
+    /// assert!(b.area() == 100);
+    /// ```
+    pub fn area(&self) -> T {
+        let diag = self.diagonal();
+        diag.x * diag.y
+    }
+}
+
+impl From<&Bound2i> for Bound2f {
+    fn from(b: &Bound2i) -> Self {
+        Self {
+            min: core::Vector2f::from(b.min),
+            max: core::Vector2f::from(b.max),
+        }
+    }
+}
+
+impl From<&Bound2f> for Bound2i {
+    fn from(b: &Bound2f) -> Self {
+        Self {
+            min: core::Vector2i::from(b.min),
+            max: core::Vector2i::from(b.max),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn create_test() -> Bound2<i32> {
+        Bound2::new(
+            &Vector2::new_xy(1, 2),
+            &Vector2::new_xy(10, 3)
+            )
+    }
+
+    #[test]
+    fn area() {
+        let b = create_test();
+
+        assert!(b.area() == 9);
+    }
+
+    #[test]
+    fn intersect_test() {
+        let b1 = Bound2i::new_xyxy(10, 10, 20, 20);
+        let b2 = Bound2i::new_xyxy(2, 11, 22, 17);
+
+        let b = b1.intersect(&b2);
+
+        assert!(
+            b.min.x == 10 &&
+            b.min.y == 11 &&
+            b.max.x == 20 &&
+            b.max.y == 17
+            )
+    }
+}
-- 
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