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Old 05-03-05, 08:45 PM   #1
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Join Date: May 2005
Posts: 4
Exclamation glDrawPixels v. slow when using GL_MAP_COLOR

To display an 1024 x 1024 image with glDrawPixels using:
glDrawPixels(X,Y,GL_RGB,GL_UNSIGNED_BYTE, bitmap);
takes about 12 ms. But if I use

glPixelTransferi(GL_MAP_COLOR, GL_TRUE);
glPixelMapfv(GL_PIXEL_MAP_I_TO_R, 256, redlut);
glPixelMapfv(GL_PIXEL_MAP_I_TO_G, 256, greenlut);
glPixelMapfv(GL_PIXEL_MAP_I_TO_B, 256, bluelut);

it takes over 700 ms to display. I note that this is similar to an earlier (Sep 2004)
report, but nothing seems to have been done since then.

Are there any solutions to this problem???

I'm running FC3 with kernel 2.6.10-770 & the 1.0-7174 driver.
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Old 05-04-05, 07:35 PM   #2
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Join Date: May 2005
Posts: 4
Default Re: glDrawPixels v. slow when using GL_MAP_COLOR

Some more info: the much maligned "nv" driver from Xorg
produces the GL_COLOR_INDEX image in 28 ms. So this is not
a code problem - there is clearly something wrong with NVIDIA
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