add support for emscripten building

src/main.c

@@ -6,18 +6,27 @@
 #include "renderer.h"
 #include "level.h"
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten/emscripten.h>
+#endif
+
 #define UPDATES_PER_SEC 50
 #define CLOCKS_PER_UPDATE (CLOCKS_PER_SEC / UPDATES_PER_SEC)
 #define CLOCKS_PER_UPDATE_F (((float)CLOCKS_PER_SEC) / UPDATES_PER_SEC)
 
+Level level = { 0 };            // stores the game's state
+SDL_Window* window = NULL;      // the window that is given to the OS
+SDL_Renderer* renderer = NULL;  // the renderer used to draw to the window
+
 // initializes the game
-static int init(SDL_Window** window, SDL_Renderer** renderer, Level* level) {
-    level_init(level);
-    return renderer_init(window, renderer);
+static int init(void) {
+    level_init(&level);
+    return renderer_init(&window, &renderer);
 }
 
+
 // called on each game update
-static bool update(Level* level, const Uint8* keys, RenderData* render_data) {
+static bool update(void) {
     const clock_t clock_start = clock();
 
     //update the event keys
@@ -32,10 +41,13 @@ static bool update(Level* level, const Uint8* keys, RenderData* render_data) {
         }
     }
 
+    RenderData render_data = { window, renderer, &level }; //contains the data which is used to render the game
+    const Uint8* keys = SDL_GetKeyboardState(NULL);
+
     // preform updates
     {
-        level_update(level, keys); //update the level
-        renderer_update(render_data); //update the render
+        level_update(&level, keys); //update the level
+        renderer_update(&render_data); //update the render
     }
 
     const clock_t clock_end = clock();
@@ -54,6 +66,15 @@ static bool update(Level* level, const Uint8* keys, RenderData* render_data) {
     return true;
 }
 
+#ifdef __EMSCRIPTEN__
+static void update_game(void) {
+    // stop updating if update returns false
+    if (update() == false) {
+        emscripten_cancel_main_loop();
+    }
+}
+#endif
+
 // cleans up resources
 static void close(SDL_Window* window, SDL_Renderer* renderer) {
     renderer_destroy(window, renderer);
@@ -61,13 +82,9 @@ static void close(SDL_Window* window, SDL_Renderer* renderer) {
 
 // entry-point of the application
 int main(void) {
-    Level level = { 0 };            //stores the game's state
-    SDL_Window* window = NULL;      //the window that is given to the OS
-    SDL_Renderer* renderer = NULL;  //the renderer used to draw to the window
-
     // initialize
     {
-        const int code = init(&window, &renderer, &level);
+        const int code = init();
         if (code != SUCCESS)
             exit(code);
     }
@@ -75,9 +92,11 @@ int main(void) {
     // TEMP: tell me that the program has been initialized
     (void)printf("initialized!\n");
 
-    // game-loop
-    RenderData render_data = { window, renderer, &level }; //contains the data which is used to render the game
-    while (update(&level, SDL_GetKeyboardState(NULL), &render_data) && (level.stop == false));
+#ifdef __EMSCRIPTEN__
+    emscripten_set_main_loop(update_game, 0, 1); // don't utilise setting the FPS, as we already do this
+#else
+    while (update() && (level.stop == false));
+#endif
 
     // frees media and shuts down SDL
     close(window, renderer);