Remove the per-vertex atmospherics support

Assets/ScriptableRenderLoop/HDRenderLoop/Sky/AtmosphericParameters.cs

 
     void UpdateKeywords(bool enable)
     {
-        Shader.DisableKeyword("ATMOSPHERICS");
-        Shader.DisableKeyword("ATMOSPHERICS_PER_PIXEL");
         Shader.DisableKeyword("ATMOSPHERICS_OCCLUSION");
         Shader.DisableKeyword("ATMOSPHERICS_OCCLUSION_FULLSKY");
         Shader.DisableKeyword("ATMOSPHERICS_OCCLUSION_EDGE_FIXUP");
         if (enable)
         {
-            Shader.EnableKeyword("ATMOSPHERICS_PER_PIXEL");
-            
             /*
             if (useOcclusion)
             {

Assets/ScriptableRenderLoop/HDRenderLoop/Sky/Resources/AtmosphericScattering.hlsl

 // Original vert/frag macros
 #if defined(ATMOSPHERICS_OCCLUSION)
     #define VOLUND_SCATTER_COORDS(idx1, idx2) float4 scatterCoords1 : TEXCOORD##idx1; float3 scatterCoords2 : TEXCOORD##idx2;
-    #if defined(ATMOSPHERICS_PER_PIXEL)
-        #define VOLUND_TRANSFER_SCATTER(pos, o) o.scatterCoords1 = pos.xyzz; o.scatterCoords2 = pos.xyz;
-        #define VOLUND_APPLY_SCATTER(i, color) VolundTransferScatterOcclusion(i.scatterCoords1.xyz, i.scatterCoords1, i.scatterCoords2); color = VolundApplyScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
-        #define VOLUND_CLOUD_SCATTER(i, color) VolundTransferScatterOcclusion(i.scatterCoords1.xyz, i.scatterCoords1, i.scatterCoords2); color = VolundApplyCloudScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
-    #else
-        #define VOLUND_TRANSFER_SCATTER(pos, o) VolundTransferScatterOcclusion(pos, o.scatterCoords1, o.scatterCoords2)
-        #define VOLUND_APPLY_SCATTER(i, color) color = VolundApplyScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
-        #define VOLUND_CLOUD_SCATTER(i, color) color = VolundApplyCloudScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
-    #endif
+    #define VOLUND_TRANSFER_SCATTER(pos, o) o.scatterCoords1 = pos.xyzz; o.scatterCoords2 = pos.xyz;
+    #define VOLUND_APPLY_SCATTER(i, color) VolundTransferScatterOcclusion(i.scatterCoords1.xyz, i.scatterCoords1, i.scatterCoords2); color = VolundApplyScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
+    #define VOLUND_CLOUD_SCATTER(i, color) VolundTransferScatterOcclusion(i.scatterCoords1.xyz, i.scatterCoords1, i.scatterCoords2); color = VolundApplyCloudScatterOcclusion(i.scatterCoords1, i.scatterCoords2, i.pos.xy, color)
-    #if defined(ATMOSPHERICS_PER_PIXEL)
-        #define VOLUND_TRANSFER_SCATTER(pos, o) o.scatterCoords1 = pos.xyzz;
-        #define VOLUND_APPLY_SCATTER(i, color) VolundTransferScatter(i.scatterCoords1.xyz, i.scatterCoords1); color = VolundApplyScatter(i.scatterCoords1, i.pos.xy, color);
-        #define VOLUND_CLOUD_SCATTER(i, color) VolundTransferScatter(i.scatterCoords1.xyz, i.scatterCoords1); color = VolundApplyCloudScatter(i.scatterCoords1, color);
-    #else
-        #define VOLUND_TRANSFER_SCATTER(pos, o) VolundTransferScatter(pos, o.scatterCoords1)
-        #define VOLUND_APPLY_SCATTER(i, color) color = VolundApplyScatter(i.scatterCoords1, i.pos.xy, color)
-        #define VOLUND_CLOUD_SCATTER(i, color) color = VolundApplyCloudScatter(i.scatterCoords1, color)
-    #endif
+    #define VOLUND_TRANSFER_SCATTER(pos, o) o.scatterCoords1 = pos.xyzz;
+    #define VOLUND_APPLY_SCATTER(i, color) VolundTransferScatter(i.scatterCoords1.xyz, i.scatterCoords1); color = VolundApplyScatter(i.scatterCoords1, i.pos.xy, color);
+    #define VOLUND_CLOUD_SCATTER(i, color) VolundTransferScatter(i.scatterCoords1.xyz, i.scatterCoords1); color = VolundApplyCloudScatter(i.scatterCoords1, color);
 #endif
 
 #if !defined(SURFACE_SCATTER_COORDS)