Added presentations from EVI 2017

EVI - 2017/EVI 21/EVIray/tracer.hpp

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+#pragma once
+#ifndef TRACER_HPP
+#define TRACER_HPP
+
+#include <vector>
+
+#include <glm/glm.hpp>
+
+#include "ray.hpp"
+#include "scene.hpp"
+
+using std::vector;
+using glm::vec2;
+using glm::vec3;
+
+// Intersection displacement bias.
+extern const float BIAS;
+
+// Default background color.
+extern const vec3 BCKG_COLOR;
+
+/**
+ * Base class for ray tracers.
+ */
+class Tracer {
+public:
+  unsigned int m_max_depth; // Max recursion depth.
+
+  Tracer(unsigned int max_depth = 5): m_max_depth(max_depth) { }
+
+  virtual ~Tracer() { }
+
+  /**
+   * Recursively trace a ray into a scene, up until the max recursion depth.
+   */
+  virtual vec3 trace_ray(Ray & r, Scene * s, unsigned int rec_level) const = 0;
+
+protected:
+  /**
+   * Fresnel law for refractions.
+   */
+  float fresnel(const vec3 & i, const vec3 & n, const float ir1, const float ir2) const;
+};
+
+#endif