HDRenderPipeline: Fix various warning in csharp and shader

ScriptableRenderPipeline/HDRenderPipeline/Lighting/TilePass/TilePass.cs

                             Texture ltcGGXMatrix = Shader.GetGlobalTexture(HDShaderIDs._LtcGGXMatrix);
                             Texture ltcDisneyDiffuseMatrix = Shader.GetGlobalTexture(HDShaderIDs._LtcDisneyDiffuseMatrix);
                             Texture ltcMultiGGXFresnelDisneyDiffuse = Shader.GetGlobalTexture(HDShaderIDs._LtcMultiGGXFresnelDisneyDiffuse);
+                            Texture gBufferTexture0 = Shader.GetGlobalTexture(HDShaderIDs._GBufferTexture0);
+                            Texture gBufferTexture1 = Shader.GetGlobalTexture(HDShaderIDs._GBufferTexture1);
+                            Texture gBufferTexture2 = Shader.GetGlobalTexture(HDShaderIDs._GBufferTexture2);
+                            Texture gBufferTexture3 = Shader.GetGlobalTexture(HDShaderIDs._GBufferTexture3);
+                            Texture ambientOcclusionTexture = Shader.GetGlobalTexture(HDShaderIDs._AmbientOcclusionTexture);
 
                             Matrix4x4 invScrProjection = Shader.GetGlobalMatrix(HDShaderIDs.g_mInvScrProjection);
                             int useTileLightList = Shader.GetGlobalInt(HDShaderIDs._UseTileLightList);
                             Vector4 cosTime = Shader.GetGlobalVector(HDShaderIDs._CosTime);
                             Vector4 unity_DeltaTime = Shader.GetGlobalVector(HDShaderIDs.unity_DeltaTime);
-                            Vector4 worldSpaceCameraPos = Shader.GetGlobalVector(HDShaderIDs._WorldSpaceCameraPos);
-                            Vector4 projectionParams = Shader.GetGlobalVector(HDShaderIDs._ProjectionParams);
-                            Vector4 screenParams = Shader.GetGlobalVector(HDShaderIDs._ScreenParams);
-                            Vector4 zbufferParams = Shader.GetGlobalVector(HDShaderIDs._ZBufferParams);
-                            Vector4 unity_OrthoParams = Shader.GetGlobalVector(HDShaderIDs.unity_OrthoParams);
                             int envLightSkyEnabled = Shader.GetGlobalInt(HDShaderIDs._EnvLightSkyEnabled);
                             float ambientOcclusionDirectLightStrenght = Shader.GetGlobalFloat(HDShaderIDs._AmbientOcclusionDirectLightStrenght);
 
                                 cmd.SetComputeBufferParam(deferredComputeShader, kernel, HDShaderIDs.g_vLightListGlobal, bUseClusteredForDeferred ? s_PerVoxelLightLists : s_LightList);
 
                                 cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._MainDepthTexture, depthTexture);
-                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture0, HDShaderIDs._GBufferTexture0);
-                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture1, HDShaderIDs._GBufferTexture1);
-                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture2, HDShaderIDs._GBufferTexture2);
-                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture3, HDShaderIDs._GBufferTexture3);
-                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._AmbientOcclusionTexture, HDShaderIDs._AmbientOcclusionTexture);
+                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture0, gBufferTexture0);
+                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture1, gBufferTexture1);
+                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture2, gBufferTexture2);
+                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._GBufferTexture3, gBufferTexture3);
+                                cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._AmbientOcclusionTexture, ambientOcclusionTexture);
 
                                 cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._LtcData, ltcData);
                                 cmd.SetComputeTextureParam(deferredComputeShader, kernel, HDShaderIDs._PreIntegratedFGD, preIntegratedFGD);

ScriptableRenderPipeline/HDRenderPipeline/Lighting/Volumetrics/VolumetricLighting.cs

     RenderTexture          m_VolumetricLightingBufferCurrentFrame = null;
     RenderTexture          m_VolumetricLightingBufferAccumulated  = null;
     RenderTargetIdentifier m_VolumetricLightingBufferCurrentFrameRT;
-    RenderTargetIdentifier m_VolumetricLightingBufferAccumulatedRT;
+   // RenderTargetIdentifier m_VolumetricLightingBufferAccumulatedRT;
 
     ComputeShader m_VolumetricLightingCS { get { return m_Asset.renderPipelineResources.volumetricLightingCS; } }
 
         m_VolumetricLightingBufferAccumulated.volumeDepth       = d;
         m_VolumetricLightingBufferAccumulated.enableRandomWrite = true;
         m_VolumetricLightingBufferAccumulated.Create();
-        m_VolumetricLightingBufferAccumulatedRT = new RenderTargetIdentifier(m_VolumetricLightingBufferAccumulated);
+       // m_VolumetricLightingBufferAccumulatedRT = new RenderTargetIdentifier(m_VolumetricLightingBufferAccumulated);
     }
 
     void ClearVolumetricLightingBuffers(CommandBuffer cmd, bool isFirstFrame)

ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/Editor/LayeredLitUI.cs

             public string[] GUIDArray;
         }
 
-        const int kMaxLayerCount = 4;
         const int kSyncButtonWidth = 58;
 
         public LayeredLitGUI()
 
         bool DoLayersGUI(AssetImporter materialImporter)
         {
-            Material material = m_MaterialEditor.target as Material;
-
             bool layerChanged = false;
 
             GUI.changed = false;

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Resources/SubsurfaceScattering.compute

     {
         // Unfortunately, our copy of HTile does not allow to accept at the tile rate.
         // Therefore, we have to additionally perform the stencil test at the pixel rate.
-        passedStencilTest = stencilRef == UnpackByte(LOAD_TEXTURE2D(_StencilTexture, pixelCoord).r);
+        passedStencilTest = (uint)stencilRef == UnpackByte(LOAD_TEXTURE2D(_StencilTexture, pixelCoord).r);
     }
 
     return passedStencilTest;

ScriptableRenderPipeline/HDRenderPipeline/Sky/ProceduralSky/Editor/ProceduralSkyEditor.cs

     [CustomEditor(typeof(ProceduralSkySettings))]
     public class ProceduralSkySettingsEditor : Editor
     {
-        private float heightFogFalloff = 1.0f;
         private float heightFogHeight = 0.0f;
 
         private class Styles