API validation improvement

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

         RTHandle                        m_DebugColorPickerBuffer;
         RTHandle                        m_DebugFullScreenTempBuffer;
         bool                            m_FullScreenDebugPushed;
-        bool                            m_NoRendering; // False by default mean we render normally, true mean we don't render anything
+        bool                            m_ValidAPI; // False by default mean we render normally, true mean we don't render anything
 
         public Material GetBlitMaterial() { return m_Blit; }
 
         {
-            SetRenderingFeatures();
+            m_ValidAPI = true;
+
+            if (!SetRenderingFeatures())
+            {
+                m_ValidAPI = false;
+
+                return ;
+            }            
 
             m_Asset = asset;
             m_GPUCopy = new GPUCopy(asset.renderPipelineResources.copyChannelCS);
         }
 
 
-        void SetRenderingFeatures()
+        bool SetRenderingFeatures()
         {
             // Set subshader pipeline tag
             Shader.globalRenderPipeline = "HDRenderPipeline";
                 Debug.LogError("High Definition Render Pipeline doesn't support Gamma mode, change to Linear mode");
             }
 #endif
-            m_NoRendering = false;
-                m_NoRendering = true;
+
+#if UNITY_EDITOR
+                foreach (UnityEditor.SceneView sv in Resources.FindObjectsOfTypeAll(typeof(UnityEditor.SceneView)))
+                    sv.ShowNotification(new GUIContent("Platform " + SystemInfo.operatingSystem + " with device " + SystemInfo.graphicsDeviceType.ToString() + " is not supported, no rendering will occur"));
+#endif                
+
+                return false;
+
+            return true;
         }
 
         bool IsSupportedPlatform()
 
         public override void Dispose()
         {
+            UnsetRenderingFeatures();
+
+            if (!m_ValidAPI)
+                return ;
+
             base.Dispose();
 
             m_DebugDisplaySettings.UnregisterDebug();
             m_IBLFilterGGX.Cleanup();
 
             DestroyRenderTextures();
-
-            UnsetRenderingFeatures();
 
 #if UNITY_EDITOR
             SceneViewDrawMode.ResetDrawMode();
         ReflectionProbeCullResults m_ReflectionProbeCullResults;
         public override void Render(ScriptableRenderContext renderContext, Camera[] cameras)
         {
-            if (m_NoRendering)
+            if (!m_ValidAPI)
                 return;
 
             base.Render(renderContext, cameras);