Fix issue with screen-space shadows not enabled with RT off (#139)

* Fix issue with screen_space shadows not enabled with RT off

* Proper fix: only keep directional screen space shadows with RT off

* Fix shadow debug mode

* cosmetic changes

Co-authored-by: sebastienlagarde <sebastien@unity3d.com>

Author: pmavridis

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

@@ -569,6 +569,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed shadowmask UI now correctly showing shadowmask disable
 - Made more explicit the warning about raytracing and asynchronous compute. Also fixed the condition in which it appears.
 - Fixed a null ref exception in static sky when the default volume profile is invalid.
+- Fixed issue with screen-space shadows not enabled properly when RT is disabled (case 1235821)
 
 ### Changed
 - Improve MIP selection for decals on Transparents

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/ScreenSpaceShadowManager.cs

@@ -246,27 +246,22 @@ void RenderScreenSpaceShadows(HDCamera hdCamera, CommandBuffer cmd)
                 return;
             }
 
-            if (hdCamera.frameSettings.IsEnabled(FrameSettingsField.RayTracing))
+            using (new ProfilingScope(cmd, ProfilingSampler.Get(HDProfileId.ScreenSpaceShadows)))
             {
-                using (new ProfilingScope(cmd, ProfilingSampler.Get(HDProfileId.ScreenSpaceShadows)))
-                {
-                    // First of all we handle the directional light
-                    RenderDirectionalLightScreenSpaceShadow(cmd, hdCamera);
+                // First of all we handle the directional light
+                RenderDirectionalLightScreenSpaceShadow(cmd, hdCamera);
 
+                if (hdCamera.frameSettings.IsEnabled(FrameSettingsField.RayTracing))
+                {
                     // We handle the other light sources
                     RenderLightScreenSpaceShadows(hdCamera, cmd);
+                }
 
-                    // We do render the debug view
-                    EvaluateShadowDebugView(cmd, hdCamera);
+                // We do render the debug view
+                EvaluateShadowDebugView(cmd, hdCamera);
 
-                    // Big the right texture
-                    cmd.SetGlobalTexture(HDShaderIDs._ScreenSpaceShadowsTexture, m_ScreenSpaceShadowTextureArray);
-                }
-            }
-            else
-            {
-                // We bind the black texture in this case
-                BindBlackShadowTexture(cmd);
+                // Bind the right texture
+                cmd.SetGlobalTexture(HDShaderIDs._ScreenSpaceShadowsTexture, m_ScreenSpaceShadowTextureArray);
             }
         }
 
@@ -911,12 +906,20 @@ void RenderPunctualScreenSpaceShadow(CommandBuffer cmd, HDCamera hdCamera
 
         void EvaluateShadowDebugView(CommandBuffer cmd, HDCamera hdCamera)
         {
-            ComputeShader shadowFilter = m_Asset.renderPipelineRayTracingResources.shadowFilterCS;
-
             // If this is the right debug mode and the index we are asking for is in the range
             HDRenderPipeline hdrp = (RenderPipelineManager.currentPipeline as HDRenderPipeline);
             if (FullScreenDebugMode.ScreenSpaceShadows == hdrp.m_CurrentDebugDisplaySettings.data.fullScreenDebugMode)
             {
+                if (!hdrp.rayTracingSupported)
+                {
+                    // In this case we have not rendered any screenspace shadows, so push a black texture on the debug display
+                    hdrp.PushFullScreenDebugTexture(hdCamera, cmd, TextureXR.GetBlackTextureArray(), FullScreenDebugMode.ScreenSpaceShadows);
+                    return;
+                }
+
+                // TODO: move the debug kernel outside of the ray tracing resources
+                ComputeShader shadowFilter = m_Asset.renderPipelineRayTracingResources.shadowFilterCS;
+
                 // Texture dimensions
                 int texWidth = hdCamera.actualWidth;
                 int texHeight = hdCamera.actualHeight;