OpenGL transparent background

Hi all,

I'm building an application who stream the content of the camera on the screen. Now I want to add a OpenGL element on the screen. My OpenGL element is an arrow that I create in a other class, that inherit GLKView call TriangleView. My ViewController is a GLKViewController. I add my Triangle View like this

View = triangleView = new TriangleView (View.Frame);

That draw my GLKView, but I would like to have a transparent background for this GLKView in order to see my camera stream. I'm beginning in OpenGL so I don't really know how to do that. I found some post that say to put an alpha on itGL.ClearColor (1.0f, 0f, 0f, 0f);,in the Draw function of my GLKView, but this doesn't work.

Any help or comment is welcome.

Thank in advance