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glDrawPixels()

Started by Xtreme Nov 6, 2000 at 6:58 PM 9 replies 800+ views

Original Post

Nov 6, 2000 at 6:58 PM

Is there a way to speed up the process of displaying a picture using glDrawPixels()? (or any other function that does the same thing?) Currently, it takes about 1-2 seconds to display a picture of size 800x600x32bit even though I have a p3-700 with a 16MB TNT video card. Why is it soooooooooo slowwwwww? What other gl Functions can I do to achieve the same thing? sig u say?

Blackstream

Nov 6, 2000 at 8:23 PM

Holy Maceral, 1-2 seconds!!! Hmmm, does your video card have OpenGL Hardware Acceleration? That could be it. I don''t really know OpenGL so I can''t get any deeper.

-Blackstream

zedzeek

Nov 6, 2000 at 8:31 PM

glDrawPixels is a slow operation, though the lastest nvidia drivers 6.xx have increased the previous speed at least 10x.
your best bet is to stick what u wanna draw into a texture and render that with a glBegin(..) glEnd() command.
BTW tnt1 aint to quick in 32bit

http://members.xoom.com/myBollux

Xtreme

Nov 6, 2000 at 8:52 PM

yeah, about 2 seconds more like it. In 16-bit mode its slightly faster, but still is slow. (about 1 second).

Yes, I''m running in OGL Hardware Acceleration. That I know.
Using texture method is faster but aren''t i''m limited to 2 to the power of n resolutions? for eg, 512x512, 256x256. I want to draw 800x600, 640x480, etc.

TheGecko

Nov 6, 2000 at 9:58 PM

Yeah I had that problem too.You have to divide your bitmap into sections of 256x256,32x32 etc and then use them all as texture maps onto your polygon.That''s what I did and it works great.