Various fix

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Lighting/HDLightEditor.cs

 
         void DrawShape()
         {
+            EditorGUI.BeginChangeCheck(); // For GI we need to detect any change on additional data and call SetLightDirty + For intensity we need to detect light shape change
+
-
-            EditorGUI.BeginChangeCheck(); // For GI we need to detect any change on additional data and call SetLightDirty
 
             // LightShape is HD specific, it need to drive LightType from the original LightType
             // when it make sense, so the GI is still in sync with the light shape
                     m_AdditionalLightData.lightTypeExtent.enumValueIndex = (int)LightTypeExtent.Rectangle;
                     EditorGUILayout.PropertyField(m_AdditionalLightData.shapeWidth, s_Styles.shapeWidthRect);
                     EditorGUILayout.PropertyField(m_AdditionalLightData.shapeHeight, s_Styles.shapeHeightRect);
+                    m_AdditionalLightData.shapeWidth.floatValue = Mathf.Max(m_AdditionalLightData.shapeWidth.floatValue, k_LineWidth);
+                    m_AdditionalLightData.shapeHeight.floatValue = Mathf.Max(m_AdditionalLightData.shapeHeight.floatValue, k_LineWidth);
                     settings.areaSizeX.floatValue = m_AdditionalLightData.shapeWidth.floatValue;
                     settings.areaSizeY.floatValue = m_AdditionalLightData.shapeHeight.floatValue;
                     settings.shadowsType.enumValueIndex = (int)LightShadows.None;
                     settings.lightType.enumValueIndex = (int)LightType.Point;
                     m_AdditionalLightData.lightTypeExtent.enumValueIndex = (int)LightTypeExtent.Line;
                     EditorGUILayout.PropertyField(m_AdditionalLightData.shapeWidth, s_Styles.shapeWidthLine);
+                    m_AdditionalLightData.shapeWidth.floatValue = Mathf.Max(m_AdditionalLightData.shapeWidth.floatValue, k_LineWidth);
+                    m_AdditionalLightData.shapeHeight.floatValue = Mathf.Max(m_AdditionalLightData.shapeHeight.floatValue, k_LineWidth);
                     // Fake line with a small rectangle in vanilla unity for GI
                     settings.areaSizeX.floatValue = m_AdditionalLightData.shapeWidth.floatValue;
                     settings.areaSizeY.floatValue = k_LineWidth;
 
             if (EditorGUI.EndChangeCheck())
             {
+                UpdateLightIntensity();
+        void UpdateLightIntensity()
+        {
+            switch (m_LightShape)
+            {
+                case LightShape.Directional:
+                    settings.intensity.floatValue = m_AdditionalLightData.directionalIntensity.floatValue;
+                    break;
+
+                case LightShape.Point:
+                    settings.intensity.floatValue = LightUtils.ConvertPointLightIntensity(m_AdditionalLightData.punctualIntensity.floatValue);
+                    break;
+
+                case LightShape.Spot:
+                    // Spot should used conversion which take into account the angle, and thus the intensity vary with angle.
+                    // This is not easy to manipulate for lighter, so we simply consider any spot light as just occluded point light. So reuse the same code.
+                    settings.intensity.floatValue = LightUtils.ConvertPointLightIntensity(m_AdditionalLightData.punctualIntensity.floatValue);
+                    // TODO: What to do with box shape ?
+                    // var spotLightShape = (SpotLightShape)m_AdditionalLightData.spotLightShape.enumValueIndex;
+                    break;
+
+                case LightShape.Rectangle:
+                    settings.intensity.floatValue = LightUtils.ConvertRectLightIntensity(m_AdditionalLightData.areaIntensity.floatValue, m_AdditionalLightData.shapeWidth.floatValue, m_AdditionalLightData.shapeHeight.floatValue);
+                    break;
+
+                case LightShape.Line:
+                    settings.intensity.floatValue = LightUtils.calculateLineLightArea(m_AdditionalLightData.areaIntensity.floatValue, k_LineWidth, m_AdditionalLightData.shapeWidth.floatValue);
+                    break;
+            }
+        }
+
         void DrawLightSettings()
         {
             settings.DrawColor();
 
             if (EditorGUI.EndChangeCheck())
             {
-                switch (m_LightShape)
-                {
-                    case LightShape.Directional:
-                        settings.intensity.floatValue = m_AdditionalLightData.directionalIntensity.floatValue;
-                        break;
-
-                    case LightShape.Point:
-                        settings.intensity.floatValue = LightUtils.ConvertPointLightIntensity(m_AdditionalLightData.punctualIntensity.floatValue);
-                        break;
-
-                    case LightShape.Spot:
-                        // Spot should used conversion which take into account the angle, and thus the intensity vary with angle.
-                        // This is not easy to manipulate for lighter, so we simply consider any spot light as just occluded point light. So reuse the same code.
-                        settings.intensity.floatValue = LightUtils.ConvertPointLightIntensity(m_AdditionalLightData.punctualIntensity.floatValue);
-                        // TODO: What to do with box shape ?
-                        // var spotLightShape = (SpotLightShape)m_AdditionalLightData.spotLightShape.enumValueIndex;
-                        break;
-
-                    case LightShape.Rectangle:
-                        settings.intensity.floatValue = LightUtils.ConvertRectLightIntensity(m_AdditionalLightData.areaIntensity.floatValue, m_AdditionalLightData.shapeWidth.floatValue, m_AdditionalLightData.shapeHeight.floatValue);
-                        break;
-
-                    case LightShape.Line:
-                        settings.intensity.floatValue = LightUtils.calculateLineLightArea(m_AdditionalLightData.areaIntensity.floatValue, k_LineWidth, m_AdditionalLightData.shapeWidth.floatValue);
-                        break;
-                }
+                UpdateLightIntensity();
             }
 
             settings.DrawLightmapping();

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightUtils.cs

         // convert intensity (lumen) to nits
         public static float ConvertSphereLightIntensity(float intensity, float sphereRadius)
         {
-            return intensity / (4.0f * Mathf.PI * sphereRadius * sphereRadius * Mathf.PI * Mathf.PI);
+            return intensity / ((4.0f * Mathf.PI * sphereRadius * sphereRadius) * Mathf.PI);
-            return intensity / (discRadius * discRadius * Mathf.PI * Mathf.PI);
+            return intensity / ((discRadius * discRadius * Mathf.PI) * Mathf.PI);
-            return intensity / (width * height * Mathf.PI);
+            return intensity / ((width * height) * Mathf.PI);
         }
 
         // convert intensity (lumen) to nits