/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
{
Exit();
}
_stopwatch.Restart();
World.Update(gameTime.ElapsedGameTime.TotalMilliseconds);
_updateTime = _stopwatch.Elapsed.TotalMilliseconds;
base.Update(gameTime);
}