XNA 4.0 Game Development by Example Beginner's Guide

Time for action – positioning the asteroids

1. Add methods to generate random locations and velocities to the AsteroidManager class:

   private Vector2 randomLocation()
   {
       Vector2 location = Vector2.Zero;
       bool locationOK = true;
       int tryCount = 0;
   
       do
       {
           locationOK = true;
           switch (rand.Next(0, 3))
           {
               case 0:
                   location.X = -initialFrame.Width;
                   location.Y = rand.Next(0, screenHeight);
                   break;
   
               case 1:
                   location.X = screenWidth;
                   location.Y = rand.Next(0, screenHeight);
                   break;
   
               case 2:
                   location.X = rand.Next(0, screenWidth);
                   location.Y = -initialFrame.Height;
                   break;
    } foreach (Sprite asteroid in Asteroids) { if (asteroid.IsBoxColliding( new Rectangle( (int)location.X, (int)location.Y, initialFrame.Width, initialFrame.Height))) { locationOK = false; } } tryCount++; ...