Added a font registry, a text rendering helper, and an FPS counter function

include/sdl3game/game.h

@@ -4,6 +4,12 @@
 #include <SDL3_mixer/SDL_mixer.h>
 #include "tilemap.h"
 
+#define GAME_AUDIO_TRACK_BGM       1
+#define GAME_AUDIO_MAX_TRACKS      64
+
+#define TIME_ONESEC_NS              1000000000
+#define TIME_ONESEC_MS              1000000
+
 /* ==================== GAME STATE VARIABLES =================== */
 
 typedef struct {
@@ -23,11 +29,15 @@ typedef struct {
     int screenwidth;
     int screenheight;
     GameState state;
+    int fps;
+    SDL_Time gameStartTime;
+    SDL_Time lastIterTime;
+    SDL_Time lastFPSTime;
+    int framesSinceUpdate;
     MIX_Mixer *mixer;
-    MIX_Track *tracks[64];
+    MIX_Track *tracks[GAME_AUDIO_MAX_TRACKS];
 } Game;
 
-#define GAME_AUDIO_TRACK_BGM       1
 
 extern SDL_Window *window;
 extern SDL_Renderer *renderer;
@@ -42,5 +52,6 @@ extern Game game;
 #define BITMASK_CLEAR(x)  x = 0;
 
 akerr_ErrorContext AKERR_NOIGNORE *GAME_init();
+void GAME_updateFPS();
 
 #endif //_GAME_H_