Added support for desktop full screen with pillarboxing and letterboxing

and started adding some comments to the code

include/AssetManager.h

@@ -22,14 +22,38 @@ typedef enum {
 } AssetType;
 typedef struct asset_manager AssetManager;
 
+/**
+ * Attempts to allocate an AssetManager object on the heap.
+ *
+ * Returns the pointer to the object when it succeeds, or NULL if it fails.
+ */
 AssetManager *create_asset_manager();
+
+/**
+ * Attempts to load an asset to the manager from a file path.
+ *
+ * Returns the AssetID on success or an INVALID_ID in the case of failure.
+ */
 AssetID load_asset_to_manager(AssetManager *am, const char *path,
                               AssetType type, Renderer *renderer);
+
+/**
+ * Removes an asset from the manager using its ID.
+ *
+ * Does nothing if the ID is not valid.
+ */
 void remove_asset_from_manager(AssetManager *am, AssetID *id_ptr);
+
 SDL_Texture *get_texture(AssetManager *am, AssetID id);
 TTF_Font *get_font(AssetManager *am, AssetID id);
 Mix_Chunk *get_audio_chunk(AssetManager *am, AssetID id);
 Mix_Music *get_music(AssetManager *am, AssetID id);
+
+/**
+ * Frees the memory allocated to the AssetManager object and performs the
+ * necessary cleanup to free all memory that were allocated to the loaded
+ * assets.
+ */
 void destroy_asset_manager(AssetManager **am);
 
 #ifdef __cplusplus