         _SpecularPower ("Specular Power", Range(0.0, 100.0)) = 5.0
         _SpecularColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1.0)
 
+        [KeywordEnum(Optimized, Optimized Loop, Conventional)]
+        _NormalCalcMode ("Normal Calculation Mode", Int) = 0
+
         [KeywordEnum(Lembert, Half Lembert, Squred Half Lembert, Disable)]
         _DiffuseMode ("Reflection Mode", Int) = 2
 

        [Toggle(_ENABLE_REFLECTION_PROBE)]
        _EnableReflectionProbe ("Enable Reflection Probe", Int) = 1

        _RefProbeBlendCoeff ("Blend coefficint of reflection probe", Range(0.0, 1.0)) = 0.5

        [Enum(UnityEngine.Rendering.CullMode)]
        _Cull ("Culling Mode", Int) = 1  // Default: Front

{
    Properties
    {
        _MaxLoop ("Maximum loop count", Int) = 256
        _MinRayLength ("Minimum length of the ray", Float) = 0.01
        _MaxRayLength ("Maximum length of the ray", Float) = 1000.0
        _Scale ("Scale vector", Vector) = (1.0, 1.0, 1.0, 1.0)
        _MarchingFactor ("Marching Factor", Float) = 1.0

