+const int LATTICE_SIZE{10};
+const double LATTICE_UNIT{1};
+const int INIT_WINDOW_POS_X{100};
+const int INIT_WINDOW_POS_Y{100};
+const int INIT_WINDOW_WIDTH{300};
+const int INIT_WINDOW_HEIGHT{300};
+const double INIT_VIEW_DISTANCE{LATTICE_SIZE * LATTICE_UNIT * 1.5};
+const double INIT_VIEW_AZIMUTH{0};
+const double INIT_VIEW_ALTITUDE{M_PI / 4};
+const char WINDOW_TITLE[]{"seamulator"};
+
+SeaPtr sea;
+WaterSurfacePtr surface;
+std::unique_ptr<SeaView> seaView;
+
+void glDisplayFunc();
+void glReshapeFunc(int width, int height);
+void glMouseFunc(int button, int state, int x, int y);
+void glMotionFunc(int x, int y);