Added support for desktop full screen with pillarboxing and letterboxing

and started adding some comments to the code

src/GameEngine.c

@@ -18,6 +18,7 @@
 #include "constants.h"
 #include "engine_build_config.h"
 #include "reusable_ids.h"
+#include <SDL2/SDL_pixels.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -130,10 +131,32 @@ bool init_engine(const char *game_name, WindowSize window_size,
 
 bool game_running() { return GameEngine.running; }
 
-WindowSize get_window_defined_size() { return GameEngine.window.defined_size; }
+void close_engine() {
+  destroy_asset_manager(&(GameEngine.asset_manager));
 
-WindowSize get_window_drawable_size() {
-  return GameEngine.window.drawable_size;
+  destroy_object_store(&(GameEngine.object_store));
+
+  destroy_window(&(GameEngine.window));
+
+  GameEngine.last_time = 0.0f;
+
+  GameEngine.delta = 0.0f;
+
+  GameEngine.running = false;
+
+  Mix_CloseAudio();
+
+  Mix_Quit();
+
+  TTF_Quit();
+
+  IMG_Quit();
+
+  SDL_Quit();
+
+#ifdef DEBUG_ENGINE
+  printf("Game closed successfully\n");
+#endif /* DEBUG_ENGINE */
 }
 
 ObjectID add_object(void *object, EventHandlerPtr event_handler,
@@ -162,6 +185,62 @@ AssetID load_asset(const char *path, AssetType type) {
                                      NULL);
 }
 
+void close_asset(AssetID *id) {
+  if (*id < 0) {
+    return;
+  }
+
+  remove_asset_from_manager(GameEngine.asset_manager, id);
+}
+
+WindowSize get_window_defined_size() { return GameEngine.window.defined_size; }
+
+WindowSize get_window_real_size() { return GameEngine.window.real_size; }
+
+WindowDrawingArea get_window_drawing_area() {
+  return GameEngine.window.drawing_area;
+}
+
+void fill_rectangle(float x, float y, float w, float h, SDL_Color color) {
+  fill_rect(GameEngine.window.renderer, color, x, y, w, h);
+}
+
+void clip_render_rect_to_drawing_area(SDL_FRect *rect) {
+  WindowDrawingArea area = get_window_drawing_area();
+
+  // If the rectangle is completely out of bounds, set its width and height to 0
+  if (rect->x > area.x + area.width || rect->x + rect->w < area.x ||
+      rect->y > area.y + area.height || rect->y + rect->h < area.y) {
+    rect->w = 0.0f;
+    rect->h = 0.0f;
+    return;
+  }
+
+  float x_diff = 0.0f;
+  float y_diff = 0.0f;
+
+  // If the rectangle is partially out of the horizontal bounds of the drawing
+  // area, calculate how much of its width will be clipped
+  if (rect->x < area.x) {
+    x_diff = area.x - rect->x;
+    rect->x += x_diff;
+  } else if (rect->x + rect->w > area.x + area.width) {
+    x_diff = (rect->x + rect->w) - (area.x + area.width);
+  }
+
+  // If the rectangle is partially out of the vertical bounds of the drawing
+  // area, calculate how much of its height will be clipped
+  if (rect->y < area.y) {
+    y_diff = area.y - rect->y;
+    rect->y += y_diff;
+  } else if (rect->y + rect->h > area.y + area.height) {
+    y_diff = (rect->y + rect->h) - (area.y + area.height);
+  }
+
+  rect->w -= x_diff;
+  rect->h -= y_diff;
+}
+
 void render_texture_asset(AssetID id, float x, float y, float w, float h) {
   if (id < 0) {
     return;
@@ -529,14 +608,6 @@ void set_playing_music_volume(int8_t volume) { Mix_VolumeMusic(volume); }
 
 bool is_music_playing() { return Mix_PlayingMusic(); }
 
-void close_asset(AssetID *id) {
-  if (*id < 0) {
-    return;
-  }
-
-  remove_asset_from_manager(GameEngine.asset_manager, id);
-}
-
 void handle_events() {
   if (!(GameEngine.running)) {
     return;
@@ -586,31 +657,3 @@ void render() {
 
   swap_render_buffers(&(GameEngine.window));
 }
-
-void close_engine() {
-  destroy_asset_manager(&(GameEngine.asset_manager));
-
-  destroy_object_store(&(GameEngine.object_store));
-
-  destroy_window(&(GameEngine.window));
-
-  GameEngine.last_time = 0.0f;
-
-  GameEngine.delta = 0.0f;
-
-  GameEngine.running = false;
-
-  Mix_CloseAudio();
-
-  Mix_Quit();
-
-  TTF_Quit();
-
-  IMG_Quit();
-
-  SDL_Quit();
-
-#ifdef DEBUG_ENGINE
-  printf("Game closed successfully\n");
-#endif /* DEBUG_ENGINE */
-}