Caching descriptor set updates

res/shaders/lib/Common.slang

@@ -48,6 +48,13 @@ float4 clipToView(float4 clip)
     return view;
 }
 
+float4 clipToWorld(float4 clip)
+{
+    float4 view = clipToView(clip);
+
+    return viewToWorld(view);
+}
+
 float4 screenToView(float4 screen)
 {
     float2 texCoord = screen.xy / pViewParams.screenDimensions;

res/shaders/lib/LightEnv.slang

@@ -52,6 +52,10 @@ struct PointLight : ILightEnv
         }
         return result;
     }
+    float3 getPosition()
+    {
+        return position_WS.xyz;
+    }
 };
 
 struct LightEnv