Progress toward stereo-ized shadows (WIP)

The shadows are building correctly, but they are not populating the ScreenSpaceShadowMap correctly (in ScreenSpaceShadows)

ScriptableRenderPipeline/LightweightPipeline/LWRP/LightweightPipeline.cs

 
                     // Only screen space shadowmap mode is supported.
                     if (shadows)
-                        ShadowCollectPass(visibleLights, ref context, ref lightData);
+                        ShadowCollectPass(visibleLights, ref context, ref lightData, frameRenderingConfiguration);
                 }
 
                 if (!shadows)
             return false;
         }
 
-        private void ShadowCollectPass(List<VisibleLight> visibleLights, ref ScriptableRenderContext context, ref LightData lightData)
+        private void ShadowCollectPass(List<VisibleLight> visibleLights, ref ScriptableRenderContext context, ref LightData lightData, FrameRenderingConfiguration frameRenderingConfiguration)
         {
             CommandBuffer cmd = CommandBufferPool.Get("Collect Shadows");
 
-            cmd.GetTemporaryRT(m_ScreenSpaceShadowMapRTID, m_CurrCamera.pixelWidth, m_CurrCamera.pixelHeight, 0, FilterMode.Bilinear, RenderTextureFormat.R8);
+            if (LightweightUtils.HasFlag(frameRenderingConfiguration, FrameRenderingConfiguration.Stereo))
+            {
+                var desc = XRSettings.eyeTextureDesc;
+                desc.depthBufferBits = 0;
+                desc.colorFormat = RenderTextureFormat.R8;
+                cmd.GetTemporaryRT(m_ScreenSpaceShadowMapRTID, desc, FilterMode.Bilinear);
+            }
+            else
+            {
+                cmd.GetTemporaryRT(m_ScreenSpaceShadowMapRTID, m_CurrCamera.pixelWidth, m_CurrCamera.pixelHeight, 0, FilterMode.Bilinear, RenderTextureFormat.R8);
+            }
+            if (LightweightUtils.HasFlag(frameRenderingConfiguration, FrameRenderingConfiguration.Stereo))
+                context.StartMultiEye(m_CurrCamera);
+
+
+            if (LightweightUtils.HasFlag(frameRenderingConfiguration, FrameRenderingConfiguration.Stereo))
+                context.StopMultiEye(m_CurrCamera);
+
             CommandBufferPool.Release(cmd);
         }
 

ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/InputBuiltin.hlsl

     return M;
 }
 
+#if defined(UNITY_SINGLE_PASS_STEREO)
+float2 TransformStereoScreenSpaceTex(float2 uv, float w)
+{
+    float4 scaleOffset = unity_StereoScaleOffset[unity_StereoEyeIndex];
+    return uv.xy * scaleOffset.xy + scaleOffset.zw * w;
+}
+
+float2 UnityStereoTransformScreenSpaceTex(float2 uv)
+{
+    return TransformStereoScreenSpaceTex(saturate(uv), 1.0);
+}
+#else
+
+#define UnityStereoTransformScreenSpaceTex(uv) uv
+
+#endif
+
 #endif // LIGHTWEIGHT_SHADER_VARIABLES_INCLUDED

ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Shadows.hlsl

 
 float4 ComputeShadowCoord(float4 clipPos)
 {
+    // TODO: This might have to be corrected for double-wide and texture arrays
     return ComputeScreenPos(clipPos);
 }
 

ScriptableRenderPipeline/LightweightPipeline/LWRP/Shaders/LightweightScreenSpaceShadows.shader

         #include "LWRP/ShaderLibrary/Core.hlsl"
         #include "LWRP/ShaderLibrary/Shadows.hlsl"
 
+#if defined(UNITY_STEREO_INSTANCING_ENABLED) || defined(UNITY_STEREO_MULTIVIEW_ENABLED)
+        TEXTURE2D_ARRAY(_CameraDepthTexture);
+        SAMPLER(sampler_CameraDepthTexture);
+#else
+#endif
 
         struct VertexInput
         {
             half4  pos      : SV_POSITION;
             half4  texcoord : TEXCOORD0;
             UNITY_VERTEX_INPUT_INSTANCE_ID
+            UNITY_VERTEX_OUTPUT_STEREO
         };
 
         Interpolators Vertex(VertexInput i)
             UNITY_TRANSFER_INSTANCE_ID(i, o);
+            UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
 
             o.pos = TransformObjectToHClip(i.vertex.xyz);
 
-            o.texcoord.xy = i.texcoord;
+            //o.texcoord.xy = i.texcoord;
+            o.texcoord.xy = UnityStereoTransformScreenSpaceTex(i.texcoord.xy);
             o.texcoord.zw = projPos.xy;
 
             return o;
         {
             UNITY_SETUP_INSTANCE_ID(i);
+            UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);
+            // TODO
+            // declare texture correctly as tex2darray
+            // pass in stereo eye index in correctly so it can sample texture
+            // Fix up sampling from a depth texture array
+#if defined(UNITY_STEREO_INSTANCING_ENABLED) || defined(UNITY_STEREO_MULTIVIEW_ENABLED)
+            float deviceDepth = SAMPLE_TEXTURE2D_ARRAY(_CameraDepthTexture, sampler_CameraDepthTexture, i.texcoord.xy, unity_StereoEyeIndex).r;
+#else
+#endif
 
 #if UNITY_REVERSED_Z
             deviceDepth = 1 - deviceDepth;