Async / await compatibility on a dedicated thread

Projects/OpenTK.Android/OpenTK.Android.csproj

@@ -10,6 +10,8 @@
     <MonoAndroidAssetsPrefix>Assets</MonoAndroidAssetsPrefix>
     <MonoAndroidResourcePrefix>Resources</MonoAndroidResourcePrefix>
     <AssemblyName>OpenTKA</AssemblyName>
+    <ProductVersion>8.0.30703</ProductVersion>
+    <SchemaVersion>2.0</SchemaVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -245,6 +247,12 @@
     <Compile Include="..\..\Source\OpenTK\Math\Quaternion.cs">
       <Link>Math\Quaternion.cs</Link>
     </Compile>
+    <Compile Include="..\..\Source\OpenTK\Math\Matrix2.cs">
+      <Link>Math\Matrix2.cs</Link>
+    </Compile>
+    <Compile Include="..\..\Source\OpenTK\Math\Matrix2d.cs">
+      <Link>Math\Matrix2d.cs</Link>
+    </Compile>
     <Compile Include="..\..\Source\OpenTK\Math\Matrix3d.cs">
       <Link>Math\Matrix3d.cs</Link>
     </Compile>
@@ -500,6 +508,21 @@
     <Compile Include="..\..\Source\OpenTK\Input\ButtonState.cs">
       <Link>Input\ButtonState.cs</Link>
     </Compile>
+    <Compile Include="..\..\Source\OpenTK\Platform\Android\Threading\IExecutionContext.cs">
+      <Link>Platform\Android\Threading\IExecutionContext.cs</Link>
+    </Compile>
+    <Compile Include="..\..\Source\OpenTK\Platform\Android\Threading\AsyncResult.cs">
+      <Link>Platform\Android\Threading\AsyncResult.cs</Link>
+    </Compile>
+    <Compile Include="..\..\Source\OpenTK\Platform\Android\Threading\BackgroundLooper.cs">
+      <Link>Platform\Android\Threading\BackgroundLooper.cs</Link>
+    </Compile>
+    <Compile Include="..\..\Source\OpenTK\Platform\Android\Threading\DelegateQueueAsyncResult.cs">
+      <Link>Platform\Android\Threading\DelegateQueueAsyncResult.cs</Link>
+    </Compile>
+    <Compile Include="..\..\Source\OpenTK\Platform\Android\Threading\Rendering_ExecutionContext_Android.cs">
+      <Link>Platform\Android\Threading\Rendering_ExecutionContext_Android.cs</Link>
+    </Compile>
     <Compile Include="..\..\Source\OpenTK\Platform\Android\AndroidGameView.cs">
       <Link>Platform\Android\AndroidGameView.cs</Link>
     </Compile>

Projects/OpenTK.Android/OpenTK.Android.sln

@@ -3,8 +3,6 @@ Microsoft Visual Studio Solution File, Format Version 11.00
 # Visual Studio 2010
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenTK.Android", "OpenTK.Android.csproj", "{9BBB96AB-86BA-45CC-9D9A-16A1432671EE}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HeaderToXml", "HeaderToXml\HeaderToXml.csproj", "{F3145268-BAFF-453A-B8F6-6E199BA4BC35}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,9 +13,5 @@ Global
 		{9BBB96AB-86BA-45CC-9D9A-16A1432671EE}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{9BBB96AB-86BA-45CC-9D9A-16A1432671EE}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{9BBB96AB-86BA-45CC-9D9A-16A1432671EE}.Release|Any CPU.Build.0 = Release|Any CPU
-		{F3145268-BAFF-453A-B8F6-6E199BA4BC35}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{F3145268-BAFF-453A-B8F6-6E199BA4BC35}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{F3145268-BAFF-453A-B8F6-6E199BA4BC35}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{F3145268-BAFF-453A-B8F6-6E199BA4BC35}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

README.md

@@ -0,0 +1,62 @@
+# AndroidGameView with async / await compatibility on a dedicated thread
+
+##Overview
+OpenTK is a set of bindings to OpenGL, OpenCL and OpenAL. This is not the main repository, it extends OpenTK for Android to work with a dedicated rendering execution context. To do so, we used a specific looper ([BackgroundLooper](http://www.codeproject.com/Articles/12082/A-DelegateQueue-Class)) that extends SynchronizationContext class.
+It is important to note that SynchronizationContext is the fundamental component of the async / await patern. For details, you can check [Parallel Programming with .Net - ExecutionContext vs SynchronizationContext](http://blogs.msdn.com/b/pfxteam/archive/2012/06/15/executioncontext-vs-synchronizationcontext.aspx)  
+When the Activity is Paused or Stopped surface and window are destroyed and to prevent loosing OpenGL context, AndroidGameView detaches it from the window and Surface (for details, please, look at this [discussion](http://forums.xamarin.com/discussion/621/androidgameview-pause-without-losing-gl-context/p2).  
+To guarantee that no OpenGL calls are made when the Activity is Paused or Stopped, we created an interface (IExecutionContext) with method Pause to stop the execution of the looper and Resume to reinitialize the execution of queued methods. This interface is used by AndroidGameView and Rendering_ExecutionContext_Android is an implementation that we provide that essentially do a set of other small things on top of BackgroundLooper like execute all queued methods before pausing the looper. 
+
+Note : in this implementation we do not provide any timer to periodically call OnRenderFrame like it happens with Run method
+
+
+##How to use
+
+1 - Create a normal OpenGL Application from the template provided by Xamarin Studio
+
+2 - Replace OpenTk by a version compiled with the code available in this repository
+
+3 - Change the creation of GLView1 (AndroidGameView child) to something like
+
+
+    public class MainActivity : Activity
+	  {
+		  GLView1 view;
+		  //To gurantee that the looper is always alive
+		  static Rendering_ExecutionContext_Android rendering_ExecutionContext = new Rendering_ExecutionContext_Android();
+
+		  protected override void OnCreate (Bundle bundle)
+		  {
+			  base.OnCreate (bundle);
+
+
+			  //Starts the looper
+			  if(rendering_ExecutionContext.State != ExecutionState.Executing)
+			  	rendering_ExecutionContext.Start ();
+
+			  view = new GLView1 (this);
+			  view.RenderingExecutionContext = rendering_ExecutionContext;
+
+
+			  SetContentView (view);
+
+	    }
+    }
+
+4 - Remove the call to Run in OnLoad overridden method
+
+5 - To Execute on Rendering thread. 
+
+		rendering_ExecutionContext.BeginInvoke(new Action(async()=>{
+				await ...
+			}), null);
+
+			rendering_ExecutionContext.BeginInvoke(new Action(()=>{
+
+			}), null);
+
+
+##Important Note
+
+
+Do not execute GL instructions before OnLoad method occurs. 
+This could be prevented by starting the looper when this method is called, but it could be useful to have the looper running to do other things that do not involve GL calls and you need them running on the same thread as OpenGL.