Example of documentation for a function

Use doxygen

Leave a single newline between function definitions

/**
* \brief Loads a 2D texture from a specified file.
* \param fileName texture's filename
* \param alpha set to true if alpha channel should be read from texture
* \return textureID
*/
	unsigned int loadTexture(const std::string &fileName, bool alpha = true);

Example of documenting a class

 /*
  * The SceneObjectsArrays class handles the vertex information of the
  * objects using arrays and draws them on the screen.
  */
class SceneObjectArrays : public SceneObject

Also describe the members of a class in the header

Documenting the menu

Preferably tooltips