How to access OpenGL rendering context on Android with Delphi XE5?

I'm going to append to this answer as new details reveal.

Attempt 1

Adding a Timer to a form and calling this procedure fills the screen with green, so that means GL context is already there:

procedure TForm1.Timer1Timer(Sender: TObject);begin  glClearColor(0, 1, 0, 0);  glClear(GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT or GL_COLOR_BUFFER_BIT);  eglSwapBuffers(TCustomAndroidContext.SharedDisplay, TCustomAndroidContext.SharedSurface);end;

Of course rendering on Timer in controlled environment is definitely a bad idea. The app kept on flickering on minimize/maximize.

Attempt 2

I have overridden TContextAndroid class (made a copy of Delphi unit and placed it into my app folder). I was able to inject custom code into DoEndScene method and it has successfully executed it - for this test just a simple glClear(GL_COLOR_BUFFER_BIT);. This has filled the entire application area with color. This time the application did not flickered and behaved just like normal.

Attempt 3

Here's the code that made it to work and that does not looks hacky:

types  TMyForm = class(TForm3D)    procedure Form3DRender(Sender: TObject; Context: TContext3D);  end;implementation//Event handler for TForm.OnRenderprocedure TMyForm.Form3DRender(Sender: TObject; Context: TContext3D);begin  glClearColor(1, 1, 0, 1);  glClear(GL_COLOR_BUFFER_BIT);end;