[#60][Doc] add missing documentation

... and sorry for the wrong mention of the issue number in my last commit... It seems I got used to the old issue number... ^^;

modules/camera/include/vkcv/camera/CameraController.hpp

@@ -61,8 +61,9 @@ namespace vkcv::camera {
         virtual void mouseButtonCallback(int button, int action, int mods, Camera &camera) = 0;
 
         /**
-         * @brief todo
-         * @param gamepadIndex
+         * @brief A callback function for gamepad input events.
+         * @param gamepadIndex The gamepad index.
+         * @param camera The camera object.
          */
         virtual void gamepadCallback(int gamepadIndex, Camera &camera) = 0;
     };

modules/camera/include/vkcv/camera/CameraManager.hpp

@@ -91,7 +91,9 @@ namespace vkcv::camera {
         void resizeCallback(int width, int height);
 
         /**
-         * @brief TODO
+         * @brief A callback function for gamepad input events. Currently, inputs are handled only for the first
+         * connected gamepad!
+         * @param gamepadIndex The gamepad index.
          */
         void gamepadCallback(int gamepadIndex);
 	

modules/camera/include/vkcv/camera/PilotCameraController.hpp

@@ -139,8 +139,9 @@ namespace vkcv::camera {
         void mouseButtonCallback(int button, int action, int mods, Camera &camera);
 
         /**
-         * @brief todo
-         * @param gamepadIndex
+         * @brief A callback function for gamepad input events.
+         * @param gamepadIndex The gamepad index.
+         * @param camera The camera object.
          */
         void gamepadCallback(int gamepadIndex, Camera &camera);
     };

modules/camera/include/vkcv/camera/TrackballCameraController.hpp

@@ -96,8 +96,9 @@ namespace vkcv::camera {
         void mouseButtonCallback(int button, int action, int mods, Camera &camera);
 
         /**
-         * @brief todo
-         * @param gamepadIndex
+         * @brief A callback function for gamepad input events.
+         * @param gamepadIndex The gamepad index.
+         * @param camera The camera object.
          */
         void gamepadCallback(int gamepadIndex, Camera &camera);
     };