/// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            camera.SetFieldSize(graphics.GraphicsDevice.Viewport);
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);
            ballsim = new BallSimulation();
            //explosionview = new Applicationview(Content, camera, spriteBatch);
            startview = new Startview(Content, camera, spriteBatch,ballsim,graphics);

            // TODO: use this.Content to load your game content here
        }
        /// <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 (Keyboard.GetState().IsKeyDown(Keys.Escape))
            {
                Exit();
            }

            if (Keyboard.GetState().IsKeyDown(Keys.R))
            {
                ballsim = new BallSimulation();
                //explosionview = new Applicationview(Content, camera, spriteBatch);
                startview = new Startview(Content, camera, spriteBatch, ballsim, graphics);
            }
            var currentmouse = Mouse.GetState();
            if (lastmouseclick.LeftButton == ButtonState.Released && currentmouse.LeftButton == ButtonState.Pressed)
            {
                startview.CreateExplosion(currentmouse.X, currentmouse.Y, spriteBatch);
            }
            lastmouseclick = currentmouse;
            ballsim.UpdateBall((float)gameTime.ElapsedGameTime.TotalSeconds);

            base.Update(gameTime);
        }