Add some faster AABB hit implementations.

Switch e?println to info/trace logging.

rtiow/src/bvh.rs

@@ -1,5 +1,6 @@
 use std;
 use std::fmt;
+use std::time::Instant;
 
 use rand;
 use rand::Rng;
@@ -43,7 +44,7 @@ impl fmt::Display for BVHNode {
 fn box_x_compare(ah: &Box<Hit>, bh: &Box<Hit>) -> std::cmp::Ordering {
     match (ah.bounding_box(0., 0.), bh.bounding_box(0., 0.)) {
         (Some(box_left), Some(box_right)) => {
-            return box_left.min.x.partial_cmp(&box_right.min.x).unwrap();
+            return box_left.min().x.partial_cmp(&box_right.min().x).unwrap();
         }
         _ => panic!("hit missing bounding box"),
     }
@@ -52,7 +53,7 @@ fn box_x_compare(ah: &Box<Hit>, bh: &Box<Hit>) -> std::cmp::Ordering {
 fn box_y_compare(ah: &Box<Hit>, bh: &Box<Hit>) -> std::cmp::Ordering {
     match (ah.bounding_box(0., 0.), bh.bounding_box(0., 0.)) {
         (Some(box_left), Some(box_right)) => {
-            return box_left.min.y.partial_cmp(&box_right.min.y).unwrap();
+            return box_left.min().y.partial_cmp(&box_right.min().y).unwrap();
         }
         _ => panic!("hit missing bounding box"),
     }
@@ -61,7 +62,7 @@ fn box_y_compare(ah: &Box<Hit>, bh: &Box<Hit>) -> std::cmp::Ordering {
 fn box_z_compare(ah: &Box<Hit>, bh: &Box<Hit>) -> std::cmp::Ordering {
     match (ah.bounding_box(0., 0.), bh.bounding_box(0., 0.)) {
         (Some(box_left), Some(box_right)) => {
-            return box_left.min.z.partial_cmp(&box_right.min.z).unwrap();
+            return box_left.min().z.partial_cmp(&box_right.min().z).unwrap();
         }
         _ => panic!("hit missing bounding box"),
     }
@@ -115,6 +116,13 @@ impl BVHNode {
             (None, None) => None,
         }
     }
+
+    fn volume(&self) -> f32 {
+        let bbox = self.bounding_box(0., 0.).unwrap();
+        (bbox.min().x - bbox.max().x).abs()
+            * (bbox.min().y - bbox.max().y).abs()
+            * (bbox.min().z - bbox.max().z).abs()
+    }
 }
 
 impl Hit for BVHNode {
@@ -152,15 +160,25 @@ pub struct BVH {
 
 impl BVH {
     pub fn new(l: Vec<Box<Hit>>, t_min: f32, t_max: f32) -> BVH {
-        BVH {
+        let count = l.len();
+        let start = Instant::now();
+        let bvh = BVH {
             root: BVHNode::new(l, t_min, t_max),
-        }
+        };
+        let runtime = start.elapsed();
+        info!(
+            "BVH build time {}.{} seconds for {} hitables",
+            runtime.as_secs(),
+            runtime.subsec_millis(),
+            count
+        );
+        bvh
     }
 }
 
 fn print_tree(f: &mut fmt::Formatter, depth: usize, bvhn: &BVHNode) -> fmt::Result {
-    // TODO(wathiede): recurse and indent
-    write!(f, "{}{}\n", " ".repeat(depth * 2), bvhn)?;
+    let vol = bvhn.volume();
+    write!(f, "{:.*}{}{}\n", 2, vol, " ".repeat(depth * 2), bvhn)?;
     if let BVHNode::Branch { left, right, .. } = bvhn {
         print_tree(f, depth + 1, left)?;
         print_tree(f, depth + 1, right)?;