From 6c1e8c7ffb32f0dfbb2fbe1abbc95b6f6ec6118b Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Sat, 21 Sep 2013 17:01:11 -0700
Subject: [PATCH] Add min_weight property to Scene

---
 src/scene.cc | 3 ++-
 src/scene.h  | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/scene.cc b/src/scene.cc
index bb2484d..d6f471f 100644
--- a/src/scene.cc
+++ b/src/scene.cc
@@ -19,6 +19,7 @@
 Scene::Scene()
     : width(640), height(480),
       max_depth(5),
+      min_weight(1e-4),
       ambient(new AmbientLight()),
       shapes(),
       lights(),
@@ -181,7 +182,7 @@ Scene::trace_ray(const Ray &ray,
                  const int depth,
                  const float weight)
 {
-    if (depth >= max_depth) {
+    if (depth >= max_depth || weight <= min_weight) {
         return Color::Black;
     }
 
diff --git a/src/scene.h b/src/scene.h
index b0eb9c7..3ac4007 100644
--- a/src/scene.h
+++ b/src/scene.h
@@ -47,8 +47,12 @@ private:
     // Pixel dimensions of the image.
     int width, height;
 
-    // Ray tracing parameters.
+    /*
+     * Ray tracing parameters. max_depth indicates the maximum depth of the ray tree. min_weight indicates the minimum
+     * specular weight to apply before giving up.
+     */
     int max_depth;
+    float min_weight;
 
     // Scene objects.
     AmbientLight *ambient;