From 78ddaff5855bf8446adef9e18eb0d7b7ddcee52a Mon Sep 17 00:00:00 2001
From: lamp
Date: Sun, 5 Mar 2023 21:45:56 +0000
Subject: init

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

(limited to 'src/hittable/aabb.rs')

diff --git a/src/hittable/aabb.rs b/src/hittable/aabb.rs
new file mode 100644
index 0000000..5c5c9fa
--- /dev/null
+++ b/src/hittable/aabb.rs
@@ -0,0 +1,46 @@
+use crate::ray::Ray;
+use crate::vec3::Point3;
+
+#[derive(Clone)]
+pub struct AABB {
+    pub minimum: Point3,
+    pub maximum: Point3,
+}
+
+impl AABB {
+    pub fn hit(&self, ray: &Ray, t_min: f64, t_max: f64) -> bool {
+        let mut t_min = t_min;
+        let mut t_max = t_max;
+        for a in 0..3 {
+            let inv_d = 1.0 / ray.direction.get(a).unwrap();
+            let mut t0 = (self.minimum.get(a).unwrap() - ray.origin.get(a).unwrap()) * inv_d;
+            let mut t1 = (self.maximum.get(a).unwrap() - ray.origin.get(a).unwrap()) * inv_d;
+            if inv_d < 0.0 {
+                // TODO: destructuring assignments are unstable :(
+                //(t0, t1) = (t1, t0);
+                std::mem::swap(&mut t0, &mut t1);
+            }
+            t_min = if t0 > t_min { t0 } else { t_min };
+            t_max = if t1 < t_max { t1 } else { t_max };
+            if t_max <= t_min {
+                return false;
+            }
+        }
+        true
+    }
+
+    pub fn surrounding_box(&self, other: &AABB) -> AABB {
+        AABB {
+            minimum: Point3 {
+                x: self.minimum.x.min(other.minimum.x),
+                y: self.minimum.y.min(other.minimum.y),
+                z: self.minimum.z.min(other.minimum.z),
+            },
+            maximum: Point3 {
+                x: self.maximum.x.max(other.maximum.x),
+                y: self.maximum.y.max(other.maximum.y),
+                z: self.maximum.z.max(other.maximum.z),
+            },
+        }
+    }
+}
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