clouds.js

 var cloudAltitude = 1e4
    , fabric = {
        type : 'Clouds',
        uniforms : {
          image : '/images/earthcloudmap.jpg',
          alphaImage : '/images/earthcloudmaptrans.jpg'
        },
        components : {
          diffuse : 'texture2D(image, materialInput.st).rgb',
          alpha : '1.0 - czm_luminance(texture2D(alphaImage, materialInput.st).rgb)'
        }
      }

  
  primitives.add(new c.EllipsoidPrimitive({
      radii : new c.Cartesian3(6378137.0 + cloudAltitude, 6378137.0 + cloudAltitude, 6356752.3142451793 + cloudAltitude)
    ,  material : new c.Material({
        fabric : fabric
      })
  }))