Upgraded OpenTK and added a cleanup

OpenTkControl/OpenTkControl.csproj

@@ -33,8 +33,8 @@
     <Prefer32Bit>false</Prefer32Bit>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="OpenTK, Version=2.0.0.0, Culture=neutral, PublicKeyToken=bad199fe84eb3df4, processorArchitecture=MSIL">
-      <HintPath>..\packages\OpenTK.2.0.0\lib\net20\OpenTK.dll</HintPath>
+    <Reference Include="OpenTK, Version=3.2.0.0, Culture=neutral, PublicKeyToken=bad199fe84eb3df4, processorArchitecture=MSIL">
+      <HintPath>..\packages\OpenTK.3.2\lib\net20\OpenTK.dll</HintPath>
     </Reference>
     <Reference Include="PresentationCore" />
     <Reference Include="PresentationFramework" />

OpenTkControl/OpenTkControlBase.xaml.cs

@@ -159,6 +159,11 @@ public GlRenderEventArgs(int width, int height, bool resized, bool screenshot, b
         /// </summary>
         public event EventHandler<GlRenderEventArgs> GlRender;
 
+        /// <summary>
+        /// Called whenever the OpenGL context is being destroyed
+        /// </summary>
+        public event EventHandler<GlRenderEventArgs> GlCleanup;
+
         /// <summary>
         /// Called whenever an exception occurs during initialization, rendering or deinitialization
         /// </summary>
@@ -289,6 +294,21 @@ protected OpenTkControlBase()
                 _alreadyLoaded = false;
                 OnUnloaded(sender, args);
             };
+
+            var currentApp = Application.Current;
+            if(currentApp != null)
+            {
+                // This handles the case of the application exiting when all the windows are closed, which
+                // wont raise the Unload event
+                currentApp.Dispatcher.ShutdownStarted += (sender, args) =>
+                {
+                    if (!_alreadyLoaded)
+                        return;
+
+                    _alreadyLoaded = false;
+                    OnUnloaded(sender, new RoutedEventArgs());
+                };
+            }
         }
 
         /// <summary>
@@ -396,6 +416,11 @@ protected void DeInitOpenGl()
         {
             try
             {
+                // With this event we give the user the chance to release all the unmanaged resources that requires
+                // the opengl context being active to be released
+                GlRenderEventArgs args = new GlRenderEventArgs(_bitmapWidth, _bitmapHeight, false, false, CheckNewContext());
+                OnGlCleanup(args);
+
                 DeInitOpenGlBuffers();
 
                 _context.Dispose();
@@ -699,5 +724,18 @@ private void OnGlRender(GlRenderEventArgs args)
             if (error != ErrorCode.NoError)
                 throw new GraphicsException(error.ToString());
         }
+
+        /// <summary>
+        /// A helper to actually invoke <see cref="GlCleanup"/>
+        /// </summary>
+        /// <param name="args">The render arguments</param>
+        private void OnGlCleanup(GlRenderEventArgs args)
+        {
+            GlCleanup?.Invoke(this, args);
+
+            ErrorCode error = GL.GetError();
+            if (error != ErrorCode.NoError)
+                throw new GraphicsException(error.ToString());
+        }
     }
 }

OpenTkControl/Properties/AssemblyInfo.cs

@@ -31,5 +31,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.0.1")]
-[assembly: AssemblyFileVersion("1.0.1")]
+[assembly: AssemblyVersion("1.0.2")]
+[assembly: AssemblyFileVersion("1.0.2")]

OpenTkControl/packages.config

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="OpenTK" version="2.0.0" />
+  <package id="OpenTK" version="3.2" targetFramework="net45" />
 </packages>