Just a little information message for Mesa3d performance on Cygwin. This is the ouput of progs/demos/readpix (from MesaDemos-6.0.1) :
- benchmark with "standard" cygwin x11 and my personnal build of glut-3.7 (static) GL_VERSION = 1.2 (1.4 Mesa 5.0.2) GL_RENDERER = Mesa GLX Indirect Loaded 194 by 188 image Benchmarking... Result: 184 reads in 4.014000 seconds = 1671860.488291 pixels/sec
With indirect rendering, the images are getting sent over a socket from the server to the client. It's not a fast path.
- benchmark with Mesa 6.0.1 DLLs (build for cygwin with my personnal patches) GL_VERSION = 1.5 Mesa 6.0.1 GL_RENDERER = Mesa X11 Loaded 194 by 188 image Benchmarking... Result: 3186 reads in 4.000000 seconds = 29049948.000000 pixels/sec
In this case, the glReadPixels is basically a memcpy() from the color buffer to the user-allocated buffer.
If you'd run stand-alone Mesa, you'd get much faster results too. I see 47103588 pixels/sec.
You should also test reading from the front color buffer too get the full picture.
-Brian
