protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
            {
                Exit();
            }

            if (Keyboard.GetState().IsKeyDown(Keys.R))
            {
                var elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;
                t += elapsed / 10f;
                if (t > 1f)
                {
                    t = 0;
                }
            }

            if (Keyboard.GetState().IsKeyDown(Keys.T))
            {
                var elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;
                t -= elapsed / 10f;
                if (t < 0f)
                {
                    t = 1f;
                }
            }

            if (Keyboard.GetState().IsKeyDown(Keys.Up))
            {
                weight += .01f;
                if (weight > 2f)
                {
                    weight = 0f;
                }
                cspline = new Curve_CatMullSpline(_wayPoints, true, weight);
            }

            ms = Mouse.GetState();
            if (ms.LeftButton == ButtonState.Pressed)
            {
                _wayPoints[0] = new Vector3(ms.Position.X, ms.Position.Y, 0);
                cspline       = new Curve_CatMullSpline(_wayPoints, true, weight);
            }

            msg = $"weight " + weight;


            if (Keyboard.GetState().IsKeyDown(Keys.Space))
            {
                _useDemoWaypoints = false;
            }
            if (Keyboard.GetState().IsKeyDown(Keys.Tab))
            {
                _useDemoWaypoints = true;
            }

            _camera.Update(_testTarget, _useDemoWaypoints, gameTime);

            base.Update(gameTime);
        }
        protected override void LoadContent()
        {
            _spriteBatch = new SpriteBatch(GraphicsDevice);
            _font        = Content.Load <SpriteFont>("MgGenFont");
            _dot         = CreateDotTexture(GraphicsDevice, Color.White);

            _camera = new WaypointCamera(GraphicsDevice, _spriteBatch, _dot, new Vector3(2, 2, 10), new Vector3(0, 0, 0), Vector3.UnitY, 0.1f, 10000f, 1f, true, false);
            _camera.TransformCamera(_camera.World.Translation, _testTarget, _camera.World.Up);
            _camera.Up = Vector3.Forward;
            _camera.WayPointCycleDurationInTotalSeconds = 20f;
            _camera.MovementSpeedPerSecond = 3f;
            _camera.SetWayPoints(_wayPoints, true, 100);

            //cspline = new CatMullSpline(_wayPoints);
            cspline = new Curve_CatMullSpline(_wayPoints, true, 0.5f);
        }