protected override void Update(GameTime gameTime)
{
var watch = System.Diagnostics.Stopwatch.StartNew();
watch.Start();
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
{
this.Exit();
}
float deltaTime = (float)gameTime.ElapsedGameTime.TotalSeconds;
deltaTime *= world.GameSpeed;
viewportManager.Update();
guiManager.Update();
world.Update(deltaTime);
fpsManager.Update(deltaTime, world.GameSpeed);
watch.Stop();
updateTime = watch.ElapsedMilliseconds;
base.Update(gameTime);
}