GL_LINE_LOOP not drawing correctly

Question

Hi, I have a square which I'm rendering using four vertices and GL_LINE_LOOP. It works fine. However, if I start to rotate this square on all axes and part of the square leaves the emulator screen, the loop appears to drop the vertex that has left the screen. I then get a triangle for a while until the fourth vertex returns to the screen and the loop draws the square again. I'm extremely new to OpenGL. Is this expected behaviour, a bug in the Android emulator, or something I've missed?

Thanks in advance for any thoughts.

Answer 1

That is not the expected behaviour.

It looks like a driver bug to me. Such bugs are not uncommon in OpenGL drivers if you use functionality that is rarely used by games.

That said: Try to render your lines using two triangles each, and the problem will be gone.