First implementation of input control with KeyStateManager

To try to do: Manage edges

src/KeyStateManager.h

@@ -0,0 +1,41 @@
+//
+// Created by trotfunky on 07/10/2019.
+//
+
+#ifndef TESTS_OPENGL_KEYSTATEMANAGER_H
+#define TESTS_OPENGL_KEYSTATEMANAGER_H
+
+#include <map>
+#include <GL/glut.h>
+
+
+/// Handles the key events from glut and keep the status of keys up to date.
+/// "Static class"
+class KeyStateManager {
+public:
+    KeyStateManager() = delete;
+
+    static void register_glut_callbacks();
+
+    // FIXME: Not happy with having two functions : char auto promoted to int if same name
+    static bool is_key_pressed(unsigned char key);
+    static bool is_special_key_pressed(int key);
+
+    // Glut callbacks for input events
+    static void key_press(unsigned char event_key, int mouse_x, int mouse_y);
+    static void key_up(unsigned char event_key, int mouse_x, int mouse_y);
+    static void special_key_press(int event_key, int mouse_x, int mouse_y);
+    static void special_key_up(int event_key, int mouse_x, int mouse_y);
+
+private:
+    // The maps are used to keep track of the keys which were pressed or released during runtime.
+    static std::map<unsigned char,bool> ascii_keys_status;
+    static std::map<int,bool> special_keys_status;
+
+    // These functions are called by *_press and *_up to update their values
+    static void update_key(unsigned char event_key, bool new_status);
+    static void update_special_key(int event_key, bool new_status);
+};
+
+
+#endif //TESTS_OPENGL_KEYSTATEMANAGER_H