Advance messages by scrolling mouse wheel down

Now the 'A' command accepts mouse wheel down events in addition to
keyboard and mouse buttons.

src/sys/nact.cpp

@@ -410,12 +410,14 @@ void NACT::cmd_a()
 		ags->draw_push(text_window);
 	}
 
+	get_wheel();  // clear wheel input
+
 	// キーが押されて離されるまで待機
 	while (!msgskip->skipping()) {
 		if(terminate) {
 			return;
 		}
-		if(get_key()) {
+		if (get_key() || get_wheel() < 0) {
 			break;
 		}
 		sys_sleep(16);

src/sys/nact.h

@@ -149,6 +149,7 @@ protected:
 	uint8 get_key();
 	void get_cursor(int* x, int* y);
 	void set_cursor(int x, int y);
+	int get_wheel();
 
 	SDL_GameController *sdl_gamecontroller = NULL;
 

src/sys/nact_input.cpp

@@ -21,7 +21,7 @@ enum TouchState {
 };
 
 extern SDL_Window* g_window;
-static int mousex, mousey;
+static int mousex, mousey, wheel;
 static TouchState touch_state = TOUCH_NONE;
 
 void NACT::handle_event(SDL_Event e)
@@ -47,6 +47,10 @@ void NACT::handle_event(SDL_Event e)
 		mousey = e.motion.y * ags->screen_height / ags->window_height;
 		break;
 
+	case SDL_MOUSEWHEEL:
+		wheel += e.wheel.y * (e.wheel.direction == SDL_MOUSEWHEEL_FLIPPED ? -1 : 1);
+		break;
+
 	case SDL_FINGERDOWN:
 	case SDL_FINGERUP:
 	case SDL_FINGERMOTION:
@@ -154,6 +158,13 @@ void NACT::set_cursor(int x, int y)
 	SDL_WarpMouseInWindow(g_window, x, y);
 }
 
+int NACT::get_wheel()
+{
+	int val = wheel;
+	wheel = 0;
+	return val;
+}
+
 void NACT::show_quit_dialog()
 {
 	const SDL_MessageBoxButtonData buttons[] = {