sphere and disk area lights mostly ready (I think :S).

disk_area_light.cpp

@@ -0,0 +1,37 @@
+#include <iostream>
+#include <cassert>
+
+#include "disk_area_light.hpp"
+#include "ray.hpp"
+
+using glm::normalize;
+
+const float BIAS = 0.000001f;
+
+vec3 DiskAreaLight::diffuse(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+  float d, att;
+  vec3 l_dir, ref;
+
+  l_dir = normalize(direction(i_pos));
+  d = distance(i_pos);
+  att = 1.0f / (m_const_att + (m_lin_att * d) + (m_quad_att * (d * d)));
+
+  return (att * m.m_brdf->diffuse(l_dir, normal, r, i_pos, m_diffuse)) / m_figure->pdf();
+}
+
+vec3 DiskAreaLight::specular(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+float d, att;
+  vec3 l_dir, ref;
+
+  l_dir = normalize(direction(i_pos));
+  d = distance(i_pos);
+  att = 1.0f / (m_const_att + (m_lin_att * d) + (m_quad_att * (d * d)));
+
+  return (att * m.m_brdf->specular(l_dir, normal, r, i_pos, m_specular, m.m_shininess)) / m_figure->pdf();
+}
+
+void DiskAreaLight::sample_at_surface(vec3 point) {
+  Disk * d = static_cast<Disk *>(m_figure);
+  m_last_sample = m_figure->sample_at_surface();
+  m_n_at_last_sample = d->m_normal;
+}