Is there any opengl state that affects coordinates used in a blit operation?
I use glBlitFrameBuffer to copy the upper half of an offscreen render buffer to the upper half of a window’s back buffer. Both source and destination have the same size (winXP + GeForce 8800GT + Opengl 3.0).
I need to do this:
glBlitFramebufferEXT( 0, 0, w, h/2, 0, h/2, w, h, GL_COLOR_BUFFER_BIT, GL_NEAREST);
instead of that (what I think should work according to the documentation):
glBlitFramebufferEXT( 0, h/2, w, h, 0, h/2, w, h, GL_COLOR_BUFFER_BIT, GL_NEAREST);
I other words, it is like source y axis is pointing down (with origin in top-left corner) and destination y axis is pointing up (with origin in lower left corner).
Is that the expected behavior?
Thanks in advance.