From 6b5f54d14d549db68033acf529994952fcfd30bc Mon Sep 17 00:00:00 2001
From: STP <adam.a.french@outlook.com>
Date: Tue, 28 Nov 2023 13:22:04 -0500
Subject: [PATCH] Added bounding boxes to own file for BVH

---
 src/bvh.rs | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 src/bvh.rs

diff --git a/src/bvh.rs b/src/bvh.rs
new file mode 100644
index 0000000..9354bbf
--- /dev/null
+++ b/src/bvh.rs
@@ -0,0 +1,46 @@
+use crate::{ray::*, EPSILON};
+use nalgebra::{Point3, Vector3};
+
+// BOUNDING BOX -----------------------------------------------------------------
+#[derive(Clone)]
+pub struct BoundingBox {
+    pub bln: Point3<f64>,
+    pub trf: Point3<f64>,
+}
+
+impl BoundingBox {
+    pub fn new(bln: Point3<f64>, trf: Point3<f64>) -> Self {
+        let bln = bln + Vector3::new(EPSILON, EPSILON, EPSILON);
+        let trf = trf - Vector3::new(EPSILON, EPSILON, EPSILON);
+        BoundingBox { bln, trf }
+    }
+    pub fn intersect_bounding_box(&self, ray: &Ray) -> bool {
+        let bln = &self.bln;
+        let trf = &self.trf;
+        let t1 = (bln - ray.a).component_div(&ray.b);
+        let t2 = (trf - ray.a).component_div(&ray.b);
+
+        let tmin = t1.inf(&t2).min();
+        let tmax = t1.sup(&t2).max();
+
+        if tmax >= tmin {
+            let intersect = ray.at_t(tmin);
+
+            // Check if the intersection is inside the box
+            if intersect.x > bln.x - EPSILON
+                || intersect.x < trf.x + EPSILON
+                || intersect.y > bln.y - EPSILON
+                || intersect.y < trf.y + EPSILON
+                || intersect.z > bln.z - EPSILON
+                || intersect.z < trf.z + EPSILON
+            {
+                return true; // Intersection is outside the box
+            }
+        }
+        false
+    }
+    #[allow(dead_code)]
+    fn get_centroid(&self) -> Point3<f64> {
+        self.bln + (self.trf - self.bln) / 2.0
+    }
+}