Add restart and handle quitting with callback

game.c

@@ -153,6 +153,11 @@ static unsigned ship_entity_id;
 static unsigned ship_shape_id;
 static unsigned fire_shape_id;
 
+static void restart()
+{
+	game_init(aspect);
+}
+
 static entity_t *add_entity(unsigned *id_out)
 {
 	const unsigned id = entity_count++;
@@ -451,6 +456,7 @@ static void handle_collisions(const collision_t *collisions, unsigned count)
 void game_init(float _aspect)
 {
 	input_on_shoot(shoot);
+	input_on_restart(restart);
 
 	aspect = _aspect;
 	dead = false;