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11-30-2004, 11:06 AM
Is there any method to draw an image held in texture memory straight to the frame buffer, without pulling it out to a bitmap first?

11-30-2004, 12:15 PM
Um... a textured quad?

And you're posting this in the Advanced forum? Boggle.

12-01-2004, 09:44 AM
God, there seems to be a smugness about these forums. OK, to avoid the obvious -> without using textured geometry! i.e. draw it as a background image in window coordinates.

12-01-2004, 09:49 AM
Um...A texture quad?

1) Orthographic projection
2) Render fullscreen textured quad
3) Perspective projection
4) draw rest of scene on top

...And you're posting this in the Advanced forum? Boggle.

12-01-2004, 10:06 AM
or maybe glDrawPixels. but that's not an advanced technique either.

12-01-2004, 10:24 AM
GreetingsFromMunich - ahh, I miss Munich - I don't think glDrawPixels meets the requirement, because you can't get a source pointer to texture memory.

geodude - actually I don't think I was being smug. I'm so rusty these days that I tend to avoid the Advanced forum myself out of embarrassment. But if you're going to ask a question which has a bleedin' obvious answer, it's only polite to explain up front why you refuse to accept that answer.

With no filtering, depth-test etc a textured quad is probably just as fast as your hypothetical pixel path. Maybe faster, since few driver writers care much about the pixel path these days.

12-01-2004, 10:30 AM
hey mike, this may be not an advanced question at all, but when were you here for the last time- don't say "in october" :p

12-01-2004, 10:45 AM
Oh, years and years ago. Around '96 I think. I was only there for about six months. And I missed the Oktoberfest by 2 weeks, dammit.

Fantastic place, though.

12-01-2004, 05:59 PM
This (http://oss.sgi.com/projects/ogl-sample/registry/ARB/wgl_buffer_region.txt) may fit your needs. Not exactly texture memory though.


The buffer region extension is a mechanism that allows an area of
an OpenGL window to be saved in off-screen memory for quick
restores. The off-screen memory can either be frame buffer memory
or system memory, although frame buffer memory might offer optimal

A buffer region can be created for the front color, back color,
depth, and/or stencil buffer. Multiple buffer regions for the same
buffer type can exist.