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View Full Version : Flip entire framebuffer upside down?



Jared@ETC
07-25-2002, 06:30 AM
Subject says what I need to do...systematically do a vertical flip of everything in the framebuffer right before it is displayed onscreen.

Flipping just the geometry (glPixelZoom, etc.) will not work in this application (don't ask).

Rob Fletcher
07-25-2002, 06:59 AM
OK, I won't ask

glMatrixMode(GL_PROJECTION);
glRotatef(180.0,0.0,0.0,1.0);
glMatrixMode(GL_MODELVIEW);

or similar, possibly???

R.

Jared@ETC
07-25-2002, 07:42 AM
Doesn't work.

coredump
07-25-2002, 07:44 AM
turn the monitor upside down

b

Jared@ETC
07-25-2002, 07:59 AM
actually, that's exactly what i'm doing http://www.opengl.org/discussion_boards/ubb/wink.gif

Jared@ETC
07-25-2002, 08:11 AM
Any other suggestions on how to do this without moving the monitor or standing on my head?

chowe6685
07-25-2002, 08:30 AM
you could render to a texture or copy the framebuffer to a texture then draw a quad with that as its texture across the entire screen

Deiussum
07-25-2002, 09:32 AM
Since you say you want a flip, not a rotate, I would guess glScalef(1.0, -1.0, 1.0) would be more appropriate. I wouldn't put it in the projection matrix, though. You can mess up lighting/fog calculations. Do that before any "Camera" transformations like gluLookAt()

Omaha
07-27-2002, 01:20 PM
WHy not just swap the signs on the top/bottom parameters when you create your frustum?