Add candela and luminance units for punctual and area lights

com.unity.render-pipelines.high-definition/HDRP/Editor/Lighting/HDLightEditor.cs

             //Disc,
         }
 
-        enum LightUnits
-        {
-            Lumen,
-            Candela,
-            Lux,
-            Luminance,
-        }
-
-        enum DirectionalLightUnits
+        enum DirectionalLightUnit
-            Lux = LightUnits.Lux,
+            Lux = LightUnit.Lux,
-        enum AreaLightUnits
+        enum AreaLightUnit
-            Lumen = LightUnits.Lumen,
-            Luminance = LightUnits.Luminance,
+            Lumen = LightUnit.Lumen,
+            Luminance = LightUnit.Luminance,
-        enum PunctualLightUnits
+        enum PunctualLightUnit
-            Lumen = LightUnits.Lumen,
-            Candela = LightUnits.Candela,
+            Lumen = LightUnit.Lumen,
+            Candela = LightUnit.Candela,
         }
 
         const float k_MinAreaWidth = 0.01f; // Provide a small size of 1cm for line light
             }*/
         }
 
-        LightUnits LightIntensityUnitPopup(LightShape shape)
+        LightUnit LightIntensityUnitPopup(LightShape shape)
+            LightUnit     selectedLightUnit;
+            LightUnit     oldLigthUnit = (LightUnit)m_AdditionalLightData.lightUnit.enumValueIndex;
+
+            EditorGUI.BeginChangeCheck();
-                    return (LightUnits)EditorGUILayout.EnumPopup((DirectionalLightUnits)m_AdditionalLightData.lightUnit.intValue);
+                    selectedLightUnit = (LightUnit)EditorGUILayout.EnumPopup((DirectionalLightUnit)m_AdditionalLightData.lightUnit.enumValueIndex);
+                    break;
-                    return (LightUnits)EditorGUILayout.EnumPopup((PunctualLightUnits)m_AdditionalLightData.lightUnit.intValue);
+                    selectedLightUnit = (LightUnit)EditorGUILayout.EnumPopup((PunctualLightUnit)m_AdditionalLightData.lightUnit.enumValueIndex);
+                    break;
-                    return (LightUnits)EditorGUILayout.EnumPopup((AreaLightUnits)m_AdditionalLightData.lightUnit.intValue);
+                    selectedLightUnit = (LightUnit)EditorGUILayout.EnumPopup((AreaLightUnit)m_AdditionalLightData.lightUnit.enumValueIndex);
+                    break;
+            if (EditorGUI.EndChangeCheck())
+                ConvertLightIntensity(oldLigthUnit, selectedLightUnit);
+
+            return selectedLightUnit;
+        }
+
+        void ConvertLightIntensity(LightUnit oldLightUnit, LightUnit newLightUnit)
+        {
+
         }
 
         void DrawLightSettings()
             EditorGUI.BeginChangeCheck();
 
+            HDAdditionalLightData d = (target as Light).GetComponent<HDAdditionalLightData>();
+
-            m_AdditionalLightData.lightUnit.intValue = (int)LightIntensityUnitPopup(m_LightShape);
+            m_AdditionalLightData.lightUnit.enumValueIndex = (int)LightIntensityUnitPopup(m_LightShape);
             EditorGUILayout.EndHorizontal();
             
             // Only display reflector option if it make sense

com.unity.render-pipelines.high-definition/HDRP/Lighting/Light/HDAdditionalLightData.cs

     };
 
     public enum SpotLightShape { Cone, Pyramid, Box };
+    
+    public enum LightUnit
+    {
+        Lumen,
+        Candela,
+        Lux,
+        Luminance,
+    }
 
     //@TODO: We should continuously move these values
     // into the engine when we can see them being generally useful
         
         public float intensity
         {
-            get { return m_Light.intensity; }
-            set { GetLightIntensity(value); }
+            get { return editorLightIntensity; }
+            set { SetLightIntensity(value); }
         }
 
         // Only for Spotlight, should be hide for other light
         public float volumetricDimmer = 1.0f;
 
         // Used internally to convert any light unit input into light intensity
-        public int  lightUnit;
+        public LightUnit lightUnit;
 
         // Not used for directional lights.
         public float fadeDistance = 10000.0f;
             }
         }
         
-        void GetLightIntensity(float value)
+        void SetLightIntensity(float intensity)
-                    GetLightIntensityPunctual(value);
+                    SetLightIntensityPunctual(intensity);
-                    m_Light.intensity = LightUtils.CalculateLineLightIntensity(value, shapeWidth);
+                    if (lightUnit == LightUnit.Lumen)
+                        m_Light.intensity = LightUtils.CalculateLineLightIntensity(intensity, shapeWidth);
+                    else
+                        m_Light.intensity = intensity;
-                    m_Light.intensity = LightUtils.ConvertRectLightIntensity(value, shapeWidth, shapeHeight);
-                    break ;
+                    if (lightUnit == LightUnit.Lumen)
+                        m_Light.intensity = LightUtils.ConvertRectLightIntensity(intensity, shapeWidth, shapeHeight);
+                    else
+                        m_Light.intensity = intensity;
+                    break;
-        void GetLightIntensityPunctual(float value)
+        void SetLightIntensityPunctual(float intensity)
-                    m_Light.intensity = directionalIntensity;
+                    m_Light.intensity = intensity; // Alwas in lux
-                    m_Light.intensity = LightUtils.ConvertPointLightIntensity(value);
+                    if (lightUnit == LightUnit.Candela)
+                        m_Light.intensity = intensity;
+                    else
+                        m_Light.intensity = LightUtils.ConvertPointLightIntensity(intensity);
-                    if (enableSpotReflector)
-
+                    if (lightUnit == LightUnit.Candela)
+                        m_Light.intensity = intensity;
+                    else if (enableSpotReflector)
-                            m_Light.intensity = LightUtils.ConvertSpotLightIntensity(value, m_Light.spotAngle * Mathf.Deg2Rad, true);
+                            m_Light.intensity = LightUtils.ConvertSpotLightIntensity(intensity, m_Light.spotAngle * Mathf.Deg2Rad, true);
                         }
                         else if (spotLightShape == SpotLightShape.Pyramid)
                         {
 
-                            m_Light.intensity = LightUtils.ConvertFrustrumLightIntensity(value, angleA, angleB);
+                            m_Light.intensity = LightUtils.ConvertFrustrumLightIntensity(intensity, angleA, angleB);
-                            m_Light.intensity = LightUtils.ConvertPointLightIntensity(value);
+                            m_Light.intensity = LightUtils.ConvertPointLightIntensity(intensity);
-                        m_Light.intensity = LightUtils.ConvertPointLightIntensity(value);
+                        m_Light.intensity = LightUtils.ConvertPointLightIntensity(intensity);
                     }
                     break;
             }