Time for action – creating a skybox

To create a skybox for Mars Runner, perform the following steps:

1. 1. Add a new class file called Skybox.cs to the Mars Runner project.

2. 2. Add the following using declaration at the beginning of the Skybox class file:

   using Microsoft.Xna.Framework;
   using Microsoft.Xna.Framework.Graphics;

3. 3. Add fields to the Skybox class as follows:

   #region Fields
   private GraphicsDevice device;
   private Texture2D texture;
   private VertexBuffer cubeVertexBuffer;
   private List<VertexPositionTexture> vertices = new
       List<VertexPositionTexture>();
   private float rotation = 0f;
   #endregion

4. 4. Create a constructor for the Skybox class as follows:

   #region Constructor
   public Skybox(
       GraphicsDevice graphicsDevice,
       Texture2D texture)
   {
       device = graphicsDevice;
       this.texture = texture;
   
       // Create the cube's vertical faces
       BuildFace(
           new Vector3(0, 0, 0), 
           new Vector3(0, 1, 1), 
           new Vector2(0, 0.25f)); // west face
       BuildFace(
   ...