From 3f78cacdd93036dbd51bae77d5d8e5430a0bc75f Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Sat, 6 Mar 2021 16:15:26 +0100
Subject: Several changes to bounding boxes

For instance removed support for shapes without a bounding box, such as
planes
---
 src/core/bound3.rs | 54 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 49 insertions(+), 5 deletions(-)

(limited to 'src/core/bound3.rs')

diff --git a/src/core/bound3.rs b/src/core/bound3.rs
index 7f54e03..ce6bb09 100644
--- a/src/core/bound3.rs
+++ b/src/core/bound3.rs
@@ -1,6 +1,6 @@
 //! Implements 3d axis aligned bounding box
 use crate::{Number, Float};
-use super::vector3::Vector3;
+use super::vector3::{Vector3, Vector3f};
 use crate::core::{min, max};
 use crate::core::Ray;
 
@@ -29,23 +29,64 @@ impl<T: Number> Bound3<T> {
 
         Self {min, max}
     }
+
+    pub fn combine(&self, op: &Self) -> Self {
+        let min = Vector3::new_xyz(
+            min(self.min.x, op.min.x),
+            min(self.min.y, op.min.y),
+            min(self.min.z, op.min.z)
+            );
+        let max = Vector3::new_xyz(
+            max(self.max.x, op.max.x),
+            max(self.max.y, op.max.y),
+            max(self.max.z, op.max.z)
+            );
+
+        Self {min, max}
+    }
+
+    pub fn and(&self, op: &Self) -> Self {
+        let min_b = Vector3::new_xyz(
+            max(self.min.x, op.min.x),
+            max(self.min.y, op.min.y),
+            max(self.min.z, op.min.z)
+            );
+        let max_b = Vector3::new_xyz(
+            min(self.max.x, op.max.x),
+            min(self.max.y, op.max.y),
+            min(self.max.z, op.max.z)
+            );
+
+        Self {min: min_b, max: max_b}
+    }
+
+    pub fn area(&self) -> T {
+        let diag = self.max - self.min;
+        diag.x * diag.y * diag.z
+    }
 }
 
 impl Bound3f {
+    pub const EMPTY: Bound3f = Bound3f{min: Vector3f::ZERO, max: Vector3f::ZERO};
+
     /// Calculate whether there is a intersect between a bounding box and a ray
     ///
     /// # Examples:
     ///
     /// ```
     /// use rendering::core::{Bound3f, Vector3f, Ray};
+    /// use rendering::INFTY;
     /// let b = Bound3f::new(Vector3f::new(7.0), Vector3f::new(10.0));
     /// let r1 = Ray::new_to(Vector3f::new(0.0), Vector3f::new(5.0));
+    /// let r2 = Ray::new_to(Vector3f::new(-0.0), Vector3f::new(-5.0));
     /// let r3 = Ray::new(Vector3f::new_xyz(-1.0, 0.0, 0.0), Vector3f::new_xyz(1.0, 0.0, 0.0));
     ///
-    /// assert!(b.intersect(&r1));
-    /// assert!(!b.intersect(&r3));
+    /// assert!(b.intersect(&r1, 0.0, INFTY));
+    /// assert!(!b.intersect(&r2, 0.0, INFTY));
+    /// assert!(!b.intersect(&r3, 0.0, INFTY));
     /// ```
-    pub fn intersect(&self, ray: &Ray) -> bool {
+    pub fn intersect(&self, ray: &Ray, t_min: Float, t_max: Float) -> bool {
+        println!("BIN: {} -> {}", self.min, self.max);
         // Method stolen from Ray tracing the next week.
         // They mention its from pixar
         for i in 0..3 {
@@ -59,7 +100,10 @@ impl Bound3f {
                 t1 = tmp;
             }
 
-            if t1 <= t0 {
+            let t_min = max(t0, t_min);
+            let t_max = min(t1, t_max);
+
+            if t_max <= t_min {
                 return false;
             }
         }
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