No no, I didn’t take that as offence. Your point is totally right. The idea to add it to the info box is good. I will reconsider it and how to add it there and think update the text. Hopefully this weekend, as I also have a Shadowing tutorial I want to publish.

Best regards

Thanks for the reply. I didn’t mean to critize Android or the demo code. It’s just that I’ve worked with OpenGL for around 10 years and with various windowing toolkits – GLAux, GLUT, fltk, Qt, SDL, and also recently OpenGL ES on the iPhone. I don’t think I’ve ever encountered any toolkit which by default permanently triggers a redraw. Not to start a pointless debate about the wisdom of this – it is true that maybe 90% of the applications need a constant redraw anyway. I am just wondering whether it would make sense to add a comment explaining this to the info box of lesson 04, as I am sure other people moving to Android from different OpenGL environments might be confused initially, too.

Yes, this is a functionality added explicitly to Android1.5 allowing to constantly or redraw by request.
The main thing here to be noted should be that OpenGL itself is not necessarily a windowing toolkit and in other cases OpenGL is also constantly redrawn but not by the UI toolkit but another threading manager. Whether its good to have this way or the other way round can be discussed. But the Android Blog says it pretty right: Most OpenGL need constant redrawing, therefore why don’t do it automatically. And for the others, use another rendermode, as you pointed out and requestRender yourself.
Of course it is possible and can be considered to do it like that all the time and handle the drawing loop yourself for e.g. fixed framerates. But this was no real part of the tutorials and can be discussed ALL DAY LONG ^^’

Best regards

From the docs:
“Using RENDERMODE_WHEN_DIRTY can improve battery life and overall system performance by allowing the GPU and CPU to idle when the view does not need to be updated.”

Haha… I would think so!

I have a question about Lesson 04: How is the redraw for the animation actually triggered? In most windowing toolkits / frameworks I know, the redraw of the OpenGL window has to be triggered explicitly somehow. However, I cannot find any such code in the Android port. Does Android simply redraw the screen continuously?

Thanks!

Yes, you are right and regarding culling you should definitely see into it. Basically why it is still in the lessons even is not needed is because of classic oldskool copy and paste of my very first Android OpenGL class I read. ^^’
So, in these lessons it is neither needed nor respected by the code besides, but for cases like starting culling it is important. But this is also important if you start reading larger chunks of vertices through any means of file formats then. And yes, standard should be ccw.

Regards