how to set up window larger than current screen size

I want to do off-screen rendering. I am trying to set up a window using glut glutinitwindowsize() function. Every time when I try to give the window size (width and height) larger than current monitor screen size, glut automatically crop to the screen size.

For example, the computer screen is 800x600, when I call glutinitwindowsize (1600, 1200), then query back the viewport size, I got 800X578.

My question is: is there a way to set up window size large than the screen size (I don’t need to display the window)?



What do you want to do ?? pbuffers or FBO might be what you’re looking for.