solution to assignment 2.2 b): eyelight shader

[MicroTrace.git] / Triangle.cxx

diff --git a/Triangle.cxx b/Triangle.cxx
index ffddbc8..456c6d8 100644 (file)
--- a/Triangle.cxx
+++ b/Triangle.cxx
@@ -2,8 +2,10 @@
 
 Triangle::Triangle(const Vec3f& a,
                   const Vec3f& b,
-                  const Vec3f& c)
-  : m_a(a),
+                  const Vec3f& c,
+                  Shader* shader)
+  : Primitive(shader),
+    m_a(a),
     m_b(b),
     m_c(c)
 {
@@ -18,34 +20,43 @@ Triangle::Intersect(Ray& ray)
 {
   const Vec3f edge1 = m_b-m_a;
   const Vec3f edge2 = m_c-m_a;
-  
+
   const Vec3f pvec = ray.direction().cross(edge2);
-  
+
   const float det = edge1.dot(pvec);
   if (fabs(det) < Epsilon) return false;
-  
+
   const float inv_det = 1.0f / det;
-  
+
   const Vec3f tvec = ray.origin()-m_a;
   float lambda = tvec.dot( pvec );
   lambda *= inv_det;
-    
-  if (lambda < 0.0f || lambda > 1.0f) 
+
+  if (lambda < 0.0f || lambda > 1.0f)
     return false;
 
   const Vec3f qvec = tvec.cross(edge1);
   float mue = ray.direction().dot(qvec);
   mue *= inv_det;
-  
-  if (mue < 0.0f || mue+lambda > 1.0f) 
+
+  if (mue < 0.0f || mue+lambda > 1.0f)
     return false;
 
   float f = edge2.dot(qvec);
   f *= inv_det;
-  if (ray.t() <= f || f <  1e-4  ) 
+  if (ray.t() <= f || f <  1e-4  )
     return false;
-  
+
   ray.setT(f);
-    
+
   return true;
 }
+
+Vec3f
+Triangle::GetNormal(Ray& ray)
+{
+  // normal is cross product of spanning vectors
+  Vec3f n = (m_c - m_a) % (m_c - m_b);
+  n.normalize();
+  return n;
+}