Cesium reflection

Reflection formula

reflect
//i It's incident light ,n Is the normalized normal

float3 reflect( float3 i, float3 n )
{
    
  return i - 2.0 * n * dot(n,i);
} 

Cesium Realization

reflect(direction, normal) {
    
      var n = Cesium.Cartesian3.dot(normal, direction);
      var t = Cesium.Cartesian3.multiplyByScalar(normal, 2 * n, new Cesium.Cartesian3);
      return Cesium.Cartesian3.subtract(direction, t, new Cesium.Cartesian3);
}