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View Full Version : Is glDrawPixels really so slooow ?



tom
05-20-2000, 07:54 AM
Hi

I wanted to have some rotating object
in front of some background pic.
I use glDrawPixels to display the pic
and then I draw the object.
But glDrawPixels() slows everything down.
Is there no other way to display a background
pic ? (Besides storing the bg pic as a texture and drawing a huge polygon)

regards
Tom

Humus
05-20-2000, 09:11 AM
I really think you should use textures since it's fastest and is no harder to use.

tom
05-20-2000, 11:07 AM
Probably you're right, but it is really
amazing how much time glDrawPixels needs
to copy a 320x240 big image into the video
ram...

Serge K
05-20-2000, 07:26 PM
I guess, glDrawPixels doesn't use temporary array to store source pixels.
It means, that glDrawPixels cannot just push some commands in the buffer for pipelined processing. It must wait, until all previous operations are complete.
It is very bad for 3D pipeline. http://www.opengl.org/discussion_boards/ubb/frown.gif