Time for action – moving the camera with the mouse

1. 1. In the TankBattlesGame class, add five fields to the declarations area:

   Point screenCenter;
   Point saveMousePoint;
   bool moveMode = false;
   float scrollRate = 1.0f;
   MouseState previousMouse;

2. 2. In the Initialize() method of the TankBattlesGame class, add the following before the call to base.Initialize():

   screenCenter.X = this.Window.ClientBounds.Width / 2;
   screenCenter.Y = this.Window.ClientBounds.Height / 2;
   
   this.IsMouseVisible = true;
   
   previousMouse = Mouse.GetState();
   Mouse.SetPosition(screenCenter.X, screenCenter.Y);

3. 3. In the Update() method of the TankBattlesGame class, add the following before the call to base.Update():

   if (this.IsActive) {
   
     MouseState mouse = Mouse.GetState();
   
     if (moveMode)
     {
         camera.Rotation += MathHelper.ToRadians(
             (mouse.X - screenCenter.X) / 2f);
         camera.Elevation += MathHelper.ToRadians(
             (mouse.Y - screenCenter.Y) / 2f);
   
         Mouse.SetPosition(screenCenter.X, screenCenter...