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

sphere_area_light.cpp

@@ -0,0 +1,45 @@
+#include "sphere_area_light.hpp"
+#include "ray.hpp"
+
+using glm::max;
+using glm::dot;
+using glm::normalize;
+
+vec3 SphereAreaLight::diffuse(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+  float d, att, ln_dot_d, d2, g;
+  vec3 l_dir, ref;
+
+  l_dir = normalize(direction(i_pos));
+  ln_dot_d = dot(-m_n_at_last_sample, l_dir);
+  if (ln_dot_d > 0.0f) {
+    d2 = glm::distance(m_last_sample, i_pos);
+    d2 *= d2;
+    g = ln_dot_d / d2;
+    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) * g) / m_figure->pdf();
+
+  } else
+    return vec3(0.0f);
+}
+
+vec3 SphereAreaLight::specular(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+  float d, att, ln_dot_d;
+  vec3 l_dir, ref;
+
+  l_dir = normalize(direction(i_pos));
+  ln_dot_d = dot(-m_n_at_last_sample, l_dir);
+  if (ln_dot_d > 0.0f) {
+    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();
+
+  } else
+    return vec3(0.0f);
+}
+
+void SphereAreaLight::sample_at_surface(vec3 point) {
+  Sphere * s = static_cast<Sphere *>(m_figure);
+  m_last_sample = m_figure->sample_at_surface();
+  m_n_at_last_sample = normalize(vec3((m_last_sample - s->m_center) / s->m_radius));
+}