Hi, > >> This looks like a list for GL_TRIANGLES instead of GL_TRIANGLE_STRIP. > >> For GL_TRIANGLE_STRIP, you first define one whole triangle (by > >> specifying each of the three vertices) and after that, each vertex > >> results in a new triangle drawn (whose two other vertices are the two > >> vertices preceding the last one). > > Thanks for the nice description. > > > > So the trick to get it done with only four vertexes is to put the > > correct points (which are going to be shared by both triangles) into the > > middle. I've played around with it a bit without success (and before my > > new opengl book arrived), and this 6-point version worked ... > > Hm, I did write a working solution in my reply, didn't I?
Yep, was just trying to explain how I ended up with the 6 vertex version, not having fully figured how triangle strips are working. All fine now, I've changed it to use 4 vertexes version instead, and I _also_ understood why it is working as intended. FYI: current code is at https://www.kraxel.org/cgit/qemu/log/?h=rebase/ui-sdl-next [ incremental fixes not squashed in yet ] thanks, Gerd