Added presentations from EVI 2017

EVI - 2017/EVI 21/EVIray/spot_light.cpp

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+#include <glm/glm.hpp>
+#include <glm/gtc/constants.hpp>
+
+#include "spot_light.hpp"
+
+using glm::pi;
+using glm::reflect;
+using glm::length;
+using glm::normalize;
+using glm::dot;
+using glm::pow;
+using glm::max;
+using glm::acos;
+using glm::radians;
+
+vec3 SpotLight::diffuse(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+  float d, att, spot_effect;
+  vec3 l_dir, ref;
+
+  l_dir = direction(i_pos);
+  d = distance(i_pos);
+  spot_effect = dot(m_spot_dir, -l_dir);
+  
+  if (acos(spot_effect) < radians(m_spot_cutoff)) {
+    spot_effect = pow(spot_effect, m_spot_exponent);
+    att = spot_effect / (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);
+
+  } else
+    return vec3(0.0f);
+}
+
+vec3 SpotLight::specular(vec3 normal, Ray & r, vec3 i_pos, Material & m) const {
+  float d, att, spot_effect;
+  vec3 l_dir, ref;
+
+  l_dir = direction(i_pos);
+  d = distance(i_pos);
+  spot_effect = dot(m_spot_dir, -l_dir);
+
+  if (acos(spot_effect) < radians(m_spot_cutoff)) {
+    spot_effect = pow(spot_effect, m_spot_exponent);
+    att = spot_effect / (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);
+  } else
+    return vec3(0.0f);
+}