Added camera abstraction.

camera.hpp

@@ -0,0 +1,51 @@
+#pragma once
+#ifndef CAMERA_HPP
+#define CAMERA_HPP
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+
+#include "ray.hpp"
+
+using glm::mat4;
+using glm::vec2;
+using glm::vec3;
+using glm::normalize;
+using glm::lookAt;
+using glm::inverse;
+
+class Camera {
+public:
+  int m_h;
+  int m_w;
+  float m_fov;
+  float m_a_ratio;
+  vec3 m_eye;
+  vec3 m_look;
+  vec3 m_up;
+
+  Camera(int h = 480, int w = 640, float fov = 90.0f, vec3 _e = vec3(0.0f), vec3 _l = vec3(0.0f, 0.0f, -1.0f), vec3 _u = vec3(0.0f, 1.0f, 0.0f)):
+    m_h(h),
+    m_w(w),
+    m_fov(fov),
+    m_eye(_e),
+    m_look(_l),
+    m_up(normalize(_u))
+  {
+    m_a_ratio = static_cast<float>(w) / static_cast<float>(h);
+    m_inv_view_matrix = inverse(lookAt(_e, _l, _u));
+  }
+
+  void reset();
+  void translate(vec3 t);
+  void pitch(float angle);
+  void yaw(float angle);
+  void roll(float angle);
+  vec2 sample_pixel(int i, int j) const;
+  void view_to_world(Ray & r) const;
+
+private:
+  mat4 m_inv_view_matrix;
+};
+
+#endif