OpenGL ES 2.0 - How can multiple views use the same renderer?

Question

Right now I have my ApplicationActivity , this activity is responsible for managing multiple views ( GLSurfaceViews ). Can / Should I have all the views set the renderer to a "global" renderer?

Code:

public class ApplicationActivity extends Activity 
{
    private static final String TAG = ApplicationActivity.class.getSimpleName();

    private final Stack<Screen> screens = new Stack<Screen>();
    private GlRenderer glRenderer;

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);

            Log.d(TAG, "Main Activity Created");

        setupGraphics();

        ChangeScreen(new MainMenu(this, glRenderer)); //Creating a new Screen sets the renderer
    }

    private void setupGraphics()
    {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,     WindowManager.LayoutParams.FLAG_FULLSCREEN);

        glRenderer = new GlRenderer(this);
    }


    public void Draw() //Is called by the glRenderer onDrawFrame() { mainActivity.Draw() } 
    {

    }
}

Its the same activity switching between GLSurfaceViews and by my knowledge I believe that the method setRenderer sets the view renderer and then starts the rendering thread (creating a new thread) but I don't want to recreate the thread every time I switch between views - may create potential problems.

So in the end I want a Renderer class just to keep graphics sepreate from business logic and such but, I don't know if using one Renderer is even possible, without setting the thread again?

Answer 1

You can only use Multiple Views with the same Renderer only if you properly switch out between them with GLSurfaceView.onPause() / .onResume();

My specific case:

@Override
protected void onPause() //Overrides onPause from Activity
{
    surfaceViews.peek().onPause();
    super.onPause();
}

So everytime the activity pauses I would have to pause the current View. And if the Activity resumes then resume the View also.

I also have a method called SetView which will either (pause and remove then change to another View) or (pause and then change to another View) this is accomplished using a Stack

public void SetView(View screen)
{   
    if (!screens.empty())
    {
        screens.peek().onPause();
        screens.pop();
    }

    screens.push(screen);
    setContentView(screens.peek());
}

Of course though because we are using Views instead of Activities now we must Override the onBackPressed() to go back to previous Views.

@Override
public void onBackPressed() 
{       
    if (screens.size() == 1)
        super.onBackPressed();
    else
    {
        screens.pop();
        setContentView(screens.peek());
        screens.peek().onResume();
    }
}

Answer 2

By doing new GLRenderer() you create new instance of your class. So there is no problem to have the same renderer used in different activities.

EDIT: I seem to misunderstand your question - if you want many GL surfaces visible at once, then no, it is not possible. But it got nothing to do with reusing renderer code.