Changed the warning message for ray traced area shadows (case 1303410). (#3029)

* - Changed the warning message for ray traced area shadows (case 1303410).

* Adds approximation information about ray-traced area shadows

Co-authored-by: Lewis Jordan <[email protected]>
Co-authored-by: sebastienlagarde <[email protected]>

Author: 3 people

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

@@ -59,6 +59,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Changed the convergence time of ssgi to 16 frames and the preset value
 - Improved robustness of volumetric sampling in path tracing (case 1295187).
 - Changed the clamping approach for RTR and RTGI (in both perf and quality) to improve visual quality.
+- Changed the warning message for ray traced area shadows (case 1303410).
 
 ## [10.3.0] - 2020-12-01
 

com.unity.render-pipelines.high-definition/Documentation~/Ray-Traced-Shadows.md

@@ -115,12 +115,13 @@ Ray-traced shadows offer the possibility of semi-transparent shadows for Point L
 Ray-traced shadows offer an alternative to the [exponential variance shadow map](Glossary.md#ExponentialVarianceShadowMap) that Rectangle Lights use for opaque GameObjects.
 
 ![](Images/RayTracedShadows7.png)
-
 **Rectangle Light shadow map**
 
 ![](Images/RayTracedShadows8.png)
 **Ray-traced Rectangle Light shadows**
 
+**Note**: When rendering in [deferred mode](Forward-And-Deferred-Rendering.md), HDRP provides accurate ray-traced area light shadows for the [Lit](Lit-Shader.md) shader. When HDRP renders for any other shader, or for the Lit shader in forward mode, it uses an approximation to calculate ray-traced shadows for area lights. This approximation is not perfectly accurate, but does produce plausible results.
+
 ### Properties
 
 | Property              | Description                                                  |
@@ -129,5 +130,6 @@ Ray-traced shadows offer an alternative to the [exponential variance shadow map]
 | **Denoise**           | Enables the spatio-temporal filter that HDRP uses to remove noise from the ray-traced shadows. |
 | - **Denoiser Radius** | Controls the radius of the spatio-temporal filter.           |
 
-### Notes
+
+## Notes
 Ray-traced shadows do not support the **Two Sided** option for the Mesh Renderer's **Cast Shadows** property. To use double-sided shadows for a mesh, open the Mesh Renderer's Material in the Inspector and, in the **Surface Options** section, enable the **Double-Sided** property.

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

@@ -1108,7 +1108,7 @@ static void DrawShadowMapContent(SerializedHDLight serialized, Editor owner)
                         {
                             if (hdrp != null && lightType == HDLightType.Area && serialized.areaLightShape == AreaLightShape.Rectangle
                                 && (hdrp.currentPlatformRenderPipelineSettings.supportedLitShaderMode != RenderPipelineSettings.SupportedLitShaderMode.DeferredOnly))
-                                EditorGUILayout.HelpBox("Ray traced area light shadows are only available in deferred mode.", MessageType.Warning);
+                                EditorGUILayout.HelpBox("Ray traced area light shadows are approximated for the Lit shader when not in deferred mode.", MessageType.Warning);
 
                             EditorGUI.indentLevel++;