Time for action – adding the ReadHeightMap() method

1. 1. Add the Height Map region to the Terrain class, shown as follows:

   #region Height Map
   private void ReadHeightMap(
       Texture2D heightMap, 
       int terrainWidth, 
       int terrainHeight, 
       float heightScale)
   {
       float min = float.MaxValue;
       float max = float.MinValue;
   
       heights = new float[terrainWidth, terrainHeight];
   
       Color[] heightMapData = new Color[
           heightMap.Width * heightMap.Height];
   
       heightMap.GetData(heightMapData);
       for (int x = 0; x < terrainWidth; x++)
           for (int z = 0; z < terrainHeight; z++)
           {
               byte height = heightMapData[x + z * terrainWidth].R;
               heights[x, z] = (float)height / 255f;
   
               max = MathHelper.Max(max, heights[x, z]);
               min = MathHelper.Min(min, heights[x, z]);
           }
   
       float range = (max - min);
   
       for (int x = 0; x < terrainWidth; x++)
           for (int z = 0; z < terrainHeight; z++)
           {
              ...