[osg-users] [Toward DrawElementBaseVertex as drawcall]

[Robert Osfield]

Hi Julien,

On 6 February 2017 at 10:33, Julien Valentin <julienvalentin51 at gmail.com> wrote:
> I remember your rejection, but it's not what I asked.
> I would like your sentiment about what the book extract says about efficient draw submission and basevertex based drawcall....

Personally I have plenty of more pressing things to work on the OSG
than chase after a possible small benefit.  For OSG-3.6 my focus will
be completing my work on fixed function -> shader pipeline and fixing
bugs.

Please remember these potential gains are in the wider context of real
application with a wider range of different potential bottlenecks,
typically the CPU and GPU bottlenecks be such that you may not see
expected benefits.

The right way to optimize graphics applications is benchmark test
cases that most closely follow the needs that your
application/OS/hardware with require when dealing with real datasets.
Narrow benchmarks won't typically reveal what bottlenecks the full
application and full data will see so you have to be very careful
about extrapolating possible bottlenecks.  With the full application
and data tests you get a real picture of the what are the biggest
bottlenecks and these are ones that you will see the most benefit from
optimizing.

Given this context I would be sceptical about how much value will see
in sharing VAO and using base vertex.  With anything that adds
complexity to the API and implementation you need to make sure there
is real value in added them to justify this complexity.

Robert.