Re: [Qemu-devel] [PATCH v2 4/7] console-gl: add opengl rendering helper functions

[Max Reitz <mreitz@redhat.com>]

On 2015-01-20 at 09:44, Gerd Hoffmann wrote:
>    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.

I see.

> All fine now, I've changed it to use 4 vertexes version instead, and I
> _also_ understood why it is working as intended.

Great. :-)

> FYI: current code is at
>    https://www.kraxel.org/cgit/qemu/log/?h=rebase/ui-sdl-next

Thanks!

Max