Cleanup comments + temp code for intermediate PR

In order to keep up with repo velocity, time to merge in the work so far toward stereo lighting.  Clean up some temp code and comments for proper merging.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Camera/HDCamera.cs

             screenSize = new Vector4(screenWidth, screenHeight, 1.0f / screenWidth, 1.0f / screenHeight);
         }
 
+        // Stopgap method used to extract stereo combined matrix state.
         public void UpdateStereoDependentState(FrameSettings frameSettings, ref ScriptableCullingParameters cullingParams)
         {
             if (!frameSettings.enableStereo)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightLoop/LightLoop.cs

                         int[]   shadowRequests = m_ShadowRequests.ToArray();
                         int[]   shadowDataIndices;
 
-                        // Stereo: The usage of camera seems to be for the camera world space position.
-                        // which corresponds to the 'center eye' position. There might be some dissonance
-                        // with the combined view pullback position.
-                        // It is used in ShadowAtlas.Reserve, for camera relative rendering, 
-                        // and ShadowManager.PruneShadowCasters.  The uses seem appropriate, but worth keeping an eye on.
                         m_ShadowMgr.ProcessShadowRequests(m_FrameId, cullResults, camera, ShaderConfig.s_CameraRelativeRendering != 0, cullResults.visibleLights,
                             ref shadowRequestCount, shadowRequests, out shadowDataIndices);
 
                     // For now we will still apply the maximum of shadow here but we don't apply the sorting by priority + slot allocation yet
 
                     // 2. Go through all lights, convert them to GPU format.
-                    // Create simultaneously data for culling (LightVolumeData and rendering)
+                    // Simultaneously create data for culling (LightVolumeData and SFiniteLightBound)
                     Vector3 camPosWS = camera.transform.position;
 
                     var worldToView = WorldToCamera(camera);
 
                 if (stereoEnabled)
                 {
-                    // TODO: Make sure decals are taken into account in the future
+                    // TODO: Proper decal + stereo cull management
+
-                    // TODO: Is this bad for the GC?
+                    // TODO: GC considerations?
                     m_lightList.bounds.AddRange(m_lightList.rightEyeBounds);
                     m_lightList.lightVolumes.AddRange(m_lightList.rightEyeLightVolumes);
                 }
                 // In stereo, we output two sets of AABB bounds
                 cmd.SetComputeBufferParam(buildScreenAABBShader, s_GenAABBKernel, HDShaderIDs.g_vBoundsBuffer, s_AABBBoundsBuffer);
 
-                // double the thread groups for stereo
                 int tgY = m_FrameSettings.enableStereo ? 2 : 1;
                 cmd.DispatchCompute(buildScreenAABBShader, s_GenAABBKernel, (m_lightCount + 7) / 8, tgY, 1);
             }
                 cmd.SetComputeIntParam(buildPerBigTileLightListShader, HDShaderIDs._EnvLightIndexShift, m_lightList.lights.Count);
                 cmd.SetComputeIntParam(buildPerBigTileLightListShader, HDShaderIDs._DecalIndexShift, m_lightList.lights.Count + m_lightList.envLights.Count);
                 cmd.SetComputeIntParam(buildPerBigTileLightListShader, HDShaderIDs.g_iNrVisibLights, m_lightCount);
-                //cmd.SetComputeMatrixParam(buildPerBigTileLightListShader, HDShaderIDs.g_mScrProjection, projscr);
-                //cmd.SetComputeMatrixParam(buildPerBigTileLightListShader, HDShaderIDs.g_mInvScrProjection, invProjscr);
+
+
                 cmd.SetComputeFloatParam(buildPerBigTileLightListShader, HDShaderIDs.g_fNearPlane, camera.nearClipPlane);
                 cmd.SetComputeFloatParam(buildPerBigTileLightListShader, HDShaderIDs.g_fFarPlane, camera.farClipPlane);
                 cmd.SetComputeBufferParam(buildPerBigTileLightListShader, s_GenListPerBigTileKernel, HDShaderIDs.g_vLightList, s_BigTileLightList);
                 cmd.SetComputeBufferParam(buildPerTileLightListShader, s_GenListPerTileKernel, HDShaderIDs._LightVolumeData, s_LightVolumeDataBuffer);
                 cmd.SetComputeBufferParam(buildPerTileLightListShader, s_GenListPerTileKernel, HDShaderIDs.g_data, s_ConvexBoundsBuffer);
 
-                //cmd.SetComputeMatrixParam(buildPerTileLightListShader, HDShaderIDs.g_mScrProjection, projscr);
-                //cmd.SetComputeMatrixParam(buildPerTileLightListShader, HDShaderIDs.g_mInvScrProjection, invProjscr);
+
                 cmd.SetComputeTextureParam(buildPerTileLightListShader, s_GenListPerTileKernel, HDShaderIDs.g_depth_tex, cameraDepthBufferRT);
                 cmd.SetComputeBufferParam(buildPerTileLightListShader, s_GenListPerTileKernel, HDShaderIDs.g_vLightList, s_LightList);
                 if (m_FrameSettings.lightLoopSettings.enableBigTilePrepass)
             }
 
             // Cluster
-            //VoxelLightListGeneration(cmd, hdCamera, projscr, invProjscr, cameraDepthBufferRT);
             VoxelLightListGeneration(cmd, hdCamera, projscrArr[0], invProjscrArr[0], cameraDepthBufferRT);
 
             if (enableFeatureVariants)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightLoop/scrbound.compute

 void ScreenBoundsAABB(uint threadID : SV_GroupIndex, uint3 u3GroupID : SV_GroupID)
 {
 	uint groupID = u3GroupID.x;
-    uint eyeIndex = u3GroupID.y; // can only be 0 or 1
+    uint eyeIndex = u3GroupID.y; // currently, can only be 0 or 1
 
     // The g_ is preserved in order to make cross-pipeline (FPTL) updates easier
     float4x4 g_mInvProjection = g_mInvProjectionArr[eyeIndex];