RE: glBegin/glEnd faster than glDrawElements?

I was using my frame rate output as the bench mark, and using DrawElements
was alot slower. It is a drawing a LOD mesh, so I have to upload the data
each frame. Does that kill any performance benefit?
The fastest performance I seem to be able to get is using tri strips and
glBegin glEnd.

  -----Original Message-----
  From: [email protected] [mailto:[email protected]]On Behalf Of
Andreas Umbach
  Sent: 06 November 2005 10:18
  To: Multiple recipients of list OPENGL-GAMEDEV-L
  Subject: Re: glBegin/glEnd faster than glDrawElements?





  On 11/1/05, William Woodbury <[email protected]> wrote:
    Hello,
    Under what circumstances is this possible? I have arrays of point,
normal,
    and uv data which represent a grid. I also have an array which
represents my
    primatives (triangles, 2 for each grid square). When I draw the entire
array
    using glDrawElements, it is slower than when I use glBegin/glEnd and
loop
    through the entire grid.

    How is this possible?

  That entirely depends on your benchmarking. Note that you can't just
measure the time of excecution from glBegin to glEnd(), because the driver's
likely not done any work between those, except preparing & filling some
command queue. The only way to benchmark this is to measure the impact the
change has on your frame rate. Also, make sure you have a sane frame rate
(e.g. between 10 - 50 fps, vsync off, etc.etc.) otherwise other factors can
throw your benchmarking way off.

  - Andreas


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