From 3e9d9dd0040fc7b578bb49bac41e8292ce16a685 Mon Sep 17 00:00:00 2001
From: Roland Hieber <rohieb@rohieb.name>
Date: Wed, 20 Jan 2010 02:34:48 +0100
Subject: [PATCH] solution to assignment 2.2 b): eyelight shader

---
 EyeLightShader.cxx | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/EyeLightShader.cxx b/EyeLightShader.cxx
index 12578d7..8eae610 100644
--- a/EyeLightShader.cxx
+++ b/EyeLightShader.cxx
@@ -1,4 +1,5 @@
 #include "EyeLightShader.hxx"
+#include "Primitive.hxx"
 
 EyeLightShader::EyeLightShader(Scene* scene,
 			       const Vec3f& color)
@@ -20,5 +21,9 @@ EyeLightShader::EyeLightShader()
 Vec3f
 EyeLightShader::Shade(Ray& ray)
 {
-  return Vec3f();
+  // shade according to cos(theta)
+  Vec3f r = ray.direction();
+  Vec3f n = ray.hit()->GetNormal(ray);
+  float cos_theta = fabs(r.dot(n) / (r.norm() * n.norm()));
+  return m_color * cos_theta;
 }
-- 
2.20.1