Add preliminary joystick support for snake example

examples/demo/01-snake/snake.c

@@ -21,6 +21,9 @@
 #define THREE_BITS  0x7U /* ~CHAR_MAX >> (CHAR_BIT - SNAKE_CELL_MAX_BITS) */
 #define SHIFT(x, y) (((x) + ((y) * SNAKE_GAME_WIDTH)) * SNAKE_CELL_MAX_BITS)
 
+static SDL_Joystick *joystick = NULL;
+
+
 typedef enum
 {
     SNAKE_CELL_NOTHING = 0U,
@@ -238,6 +241,26 @@ static SDL_AppResult handle_key_event_(SnakeContext *ctx, SDL_Scancode key_code)
     return SDL_APP_CONTINUE;
 }
 
+static SDL_AppResult handle_hat_event_(SnakeContext *ctx, Uint8 hat) {
+		switch (hat) {
+		case SDL_HAT_RIGHT:
+			snake_redir(ctx, SNAKE_DIR_RIGHT);
+			break;
+		case SDL_HAT_UP:
+			snake_redir(ctx, SNAKE_DIR_UP);
+			break;
+		case SDL_HAT_LEFT:
+			snake_redir(ctx, SNAKE_DIR_LEFT);
+			break;
+		case SDL_HAT_DOWN:
+			snake_redir(ctx, SNAKE_DIR_DOWN);
+			break;
+		default:
+				break;
+		}
+		return SDL_APP_CONTINUE;
+}
+
 SDL_AppResult SDL_AppIterate(void *appstate)
 {
     AppState *as = (AppState *)appstate;
@@ -305,7 +328,8 @@ SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
         }
     }
 
-    if (!SDL_Init(SDL_INIT_VIDEO)) {
+    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK)) {
+				SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
         return SDL_APP_FAILURE;
     }
 
@@ -316,7 +340,7 @@ SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
 
     *appstate = as;
 
-    if (!SDL_CreateWindowAndRenderer("examples/demo/snake", SDL_WINDOW_WIDTH, SDL_WINDOW_HEIGHT, 0, &as->window, &as->renderer)) {
+    if (!SDL_CreateWindowAndRenderer("examples/snake", SDL_WINDOW_WIDTH, SDL_WINDOW_HEIGHT, 0, &as->window, &as->renderer)) {
         return SDL_APP_FAILURE;
     }
 
@@ -333,6 +357,20 @@ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
     switch (event->type) {
     case SDL_EVENT_QUIT:
         return SDL_APP_SUCCESS;
+		case SDL_EVENT_JOYSTICK_ADDED:
+				if (joystick == NULL) {
+					joystick = SDL_OpenJoystick(event->jdevice.which);
+					if (!joystick) {
+						SDL_Log("Failed to open joystick ID %u: %s", (unsigned int) event->jdevice.which, SDL_GetError());
+					}
+				}
+		case SDL_EVENT_JOYSTICK_REMOVED:
+				if (joystick && (SDL_GetJoystickID(joystick) == event->jdevice.which)) {
+					SDL_CloseJoystick(joystick);
+					joystick = NULL;
+				}
+		case SDL_EVENT_JOYSTICK_HAT_MOTION:
+				return handle_hat_event_(ctx, event->jhat.value);
     case SDL_EVENT_KEY_DOWN:
         return handle_key_event_(ctx, event->key.scancode);
     }
@@ -341,6 +379,9 @@ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
 
 void SDL_AppQuit(void *appstate, SDL_AppResult result)
 {
+		if (joystick) {
+			SDL_CloseJoystick(joystick);
+		}
     if (appstate != NULL) {
         AppState *as = (AppState *)appstate;
         SDL_DestroyRenderer(as->renderer);