Fix Undo/Redo Stability for Light Temperature (1304176, 1301076)

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed GC allocations from XR occlusion mesh when using multipass.
 - Fixed XR depth copy when using MSAA.
 - Fixed after post process custom pass scale issue when dynamic resolution is enabled (case 1299194).
+- Fixed Undo/Redo instability of light temperature.
 
 ### Changed
 - Change the source value for the ray tracing frame index iterator from m_FrameCount to the camera frame count (case 1301356).

com.unity.render-pipelines.high-definition/Editor/Lighting/LightUnit/LightUnitSlider.cs

@@ -569,12 +569,14 @@ void SliderWithTextureNoTextField(Rect rect, ref float value, Vector2 range, Lig
             // Draw the exponential slider that fits 6500K to the white point on the gradient texture.
             var internalValue = GUI.HorizontalSlider(rect, ValueToSlider(value), 0f, 1f, SliderStyles.k_TemperatureBorder, SliderStyles.k_TemperatureThumb);
 
-            // Map the value back into kelvin.
-            value = SliderToValue(internalValue);
-
             // Round to nearest since so much precision is not necessary for kelvin while sliding.
             if (EditorGUI.EndChangeCheck())
+            {
+                // Map the value back into kelvin.
+                value = SliderToValue(internalValue);
+
                 value = Mathf.Round(value);
+            }
         }
     }