[self-interest] OpenGL
Steve Dekorte
steve at dekorte.com
Mon Jun 16 02:48:52 UTC 2003
On Friday, June 13, 2003, at 07:27 PM, Jecel Assumpcao Jr wrote:
> On Wed, 11 Jun 2003 19:18:33 -0700, Steve Dekorte wrote:
>> The characters are rendered from a texture, so you could certainly
>> render them onto a surface if you wanted to. Either way, you get
>> excellent performance because you keep the data close to the logic and
>> let the graphics hw do the heavy lifting.
>
> Ok. OpenGL is an immediate mode renderer, right? This wouldn't be as
> easy in a retained mode one.
I'm not sure what you mean. If you mean you want to keep a copy of a
frame buffer and draw over it, you can do that in-hardware using OpenGL
too.
Maybe it's best to put this to a test. This test isn't perfect, but
it's simple and might be useful for ball-park figure comparisons.
Here's a sample program:
http://www.dekorte.com/Library/GLTest/polygons.c
It's set up to draw 15000 polygons and then swap the buffers. It
measures the performance about once per second. Here are the results on
my year-old OSX box:
[max:~] steve% ./a.out
polygons per second = 911764, frames per second = 62
polygons per second = 1014705, frames per second = 69
polygons per second = 980198, frames per second = 66
polygons per second = 1014705, frames per second = 69
polygons per second = 1009900, frames per second = 68
polygons per second = 950495, frames per second = 64
polygons per second = 980198, frames per second = 66
So about a million smooth shaded 24bit color polygons per second. I
would guess that performance on texture mapped polygons (such as text)
wouldn't be much different and would more dramatically illustrate the
performance difference, but I wanted to keep this test simple.
Can someone put together a similar Xlib/Linux or CoreGraphics/OSX demo
to compare this to?
Cheers,
Steve
Io, a small language: http://www.iolanguage.com/
More information about the Self-interest
mailing list