Flip entire framebuffer upside down?

OpenGL OpenGL: Advanced Coding
1

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).

2

Hi

I would render it to a texture and then render a full screen quad with prober texture coordinates. You could either do a glCopySubTexImage or using the WGL_render_texture extension or perhaps the NV_texture_rectangle extension

Bye
ScottManDeath

3

if possible, you could render everything upside down as well… depends on the exact problem, but possibly is a solution as well…

or turn your screen upside down…

4

Scale the projection matrix with glScale(1,-1,1);

that might screw up some other calcs like fog, but as we cant ask you what its for, maybe that will help

5

Originally posted by Mazy:
[b]Scale the projection matrix with glScale(1,-1,1);

that might screw up some other calcs like fog, but as we cant ask you what its for, maybe that will help[/b]

this helps only, when you also reverse your backfaceculling function.

6

I don’t know if this solves your problem, but I just negate the FOV in gluPerspective(). Like so:
gluPerspective(-45.0, screenWidth/screenHeight, 1.0, 100.0);

Bode