HDRenderPipeline: Re-add "none" mode for double sided lighting

This may be use for hair card. Double sided mode now have none, mirror
and flip mode

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLit.shader

         [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
 
         [ToggleOff] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [ToggleOff] _DoubleSidedMirrorEnable("Double sided mirror enable", Float) = 1.0
+        [Enum(None, 0, Mirror, 1, Flip, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [ToggleOff]  _EnablePerPixelDisplacement("Enable per pixel displacement", Float) = 0.0
             #define DEBUG_DISPLAY
             #define SHADERPASS SHADERPASS_FORWARD
             #include "../../Debug/DebugDisplay.hlsl"
-            #include "../../Lighting/Forward.hlsl"            
+            #include "../../Lighting/Forward.hlsl"
             // TEMP until pragma work in include
             #pragma multi_compile LIGHTLOOP_SINGLE_PASS LIGHTLOOP_TILE_PASS
 

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLitTessellation.shader

         [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
 
         [ToggleOff] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [ToggleOff] _DoubleSidedMirrorEnable("Double sided mirror enable", Float) = 1.0
+        [Enum(None, 0, Mirror, 1, Flip, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [ToggleOff]  _EnablePerPixelDisplacement("Enable per pixel displacement", Float) = 0.0

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Editor/BaseLitUI.cs

     {
         protected static class StylesBaseLit
         {
-            public static GUIContent doubleSidedMirrorEnableText = new GUIContent("Mirror normal", "This will mirror the normal with vertex normal plane if enabled, else flip the normal");
+            public static GUIContent doubleSidedNormalModeText = new GUIContent("Normal mode", "This will modify the normal base on the selected mode. None: untouch, Mirror: Mirror the normal with vertex normal plane, Flip: Flip the normal");
             public static GUIContent depthOffsetEnableText = new GUIContent("Enable Depth Offset", "EnableDepthOffset on this shader (Use with heightmap)");
 
             // Material ID
             public static string vertexAnimation = "Vertex Animation";
         }
 
+        public enum DoubleSidedNormalMode
+        {
+           None,
+           Mirror,
+           Flip
+        }
+
         public enum TessellationMode
         {
             Phong,
 
-        protected MaterialProperty doubleSidedMirrorEnable = null;
-        protected const string kDoubleSidedMirrorEnable = "_DoubleSidedMirrorEnable";
+        protected MaterialProperty doubleSidedNormalMode = null;
+        protected const string kDoubleSidedNormalMode = "_DoubleSidedNormalMode";
         protected MaterialProperty depthOffsetEnable = null;
         protected const string kDepthOffsetEnable = "_DepthOffsetEnable";
 
         {
             base.FindBaseMaterialProperties(props);
 
-            doubleSidedMirrorEnable = FindProperty(kDoubleSidedMirrorEnable, props);
+            doubleSidedNormalMode = FindProperty(kDoubleSidedNormalMode, props);
             depthOffsetEnable = FindProperty(kDepthOffsetEnable, props);
 
             // MaterialID
             if (doubleSidedEnable.floatValue > 0.0f)
             {
                 EditorGUI.indentLevel++;
-                m_MaterialEditor.ShaderProperty(doubleSidedMirrorEnable, StylesBaseLit.doubleSidedMirrorEnableText);
+                m_MaterialEditor.ShaderProperty(doubleSidedNormalMode, StylesBaseLit.doubleSidedNormalModeText);
                 EditorGUI.indentLevel--;
             }
 
             SetupBaseUnlitKeywords(material);
 
             bool doubleSidedEnable = material.GetFloat(kDoubleSidedEnable) > 0.0f;
-            bool doubleSidedMirrorEnable = material.GetFloat(kDoubleSidedMirrorEnable) > 0.0f;
-                if (doubleSidedMirrorEnable)
+                DoubleSidedNormalMode doubleSidedNormalMode = (DoubleSidedNormalMode)material.GetFloat(kDoubleSidedNormalMode);
+                switch (doubleSidedNormalMode)
-                    // Mirror mode (in tangent space)
-                    material.SetVector("_DoubleSidedConstants", new Vector4(1.0f, 1.0f, -1.0f, 0.0f));
-                }
-                else
-                {
-                    // Flip mode (in tangent space)
-                    material.SetVector("_DoubleSidedConstants", new Vector4(-1.0f, -1.0f, -1.0f, 0.0f));
+                    case DoubleSidedNormalMode.None:
+                        material.SetVector("_DoubleSidedConstants", new Vector4(1.0f, 1.0f, 1.0f, 0.0f));
+                        break;
+
+                    case DoubleSidedNormalMode.Mirror: // Mirror mode (in tangent space)
+                        material.SetVector("_DoubleSidedConstants", new Vector4(1.0f, 1.0f, -1.0f, 0.0f));
+                        break;
+
+                    case DoubleSidedNormalMode.Flip: // Flip mode (in tangent space)
+                        material.SetVector("_DoubleSidedConstants", new Vector4(-1.0f, -1.0f, -1.0f, 0.0f));
+                        break;
                 }
             }
 

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.shader

         [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
 
         [ToggleOff] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [ToggleOff] _DoubleSidedMirrorEnable("Double sided mirror enable", Float) = 1.0
+        [Enum(None, 0, Mirror, 1, Flip, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [Enum(UV0, 0, Planar, 1, TriPlanar, 2)] _UVBase("UV Set for base", Float) = 0

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitTessellation.shader

         [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
 
         [ToggleOff] _DoubleSidedEnable("Double sided enable", Float) = 0.0
-        [ToggleOff] _DoubleSidedMirrorEnable("Double sided mirror enable", Float) = 1.0
+        [Enum(None, 0, Mirror, 1, Flip, 2)] _DoubleSidedNormalMode("Double sided normal mode", Float) = 1
         [HideInInspector] _DoubleSidedConstants("_DoubleSidedConstants", Vector) = (1, 1, -1, 0)
 
         [Enum(UV0, 0, Planar, 1, TriPlanar, 2)] _UVBase("UV Set for base", Float) = 0