FBO for screenshoting in high resolution


I would like to use FBO in order to take screenshots in a higher resolution than the actual desktop resolution.

I had a try and I am actually able to store a high resolution screenshots… but only a corner of it is actually filled with the screen display…
How can I allow the display to be resize to actually occupy the full texture space.

Is it possible?

Thanks in advance,

You need to setup the viewport properly. If you forget that, you will continue rendering only to a piece of the FBO.


It is now working…
thanks a lot for the Clever idea…


And in case you were wondering at this point :slight_smile: - the way to do screenshots larger than the maximum FBO-size, is to divide your view-frustum into several slices, setting it up with glFrustum for maximum control over your projection matrix - and then combine manually before writing out the image.

Mikkel can you tellme how to divide the view frustum
I have tried and have not got it working yet

is there a examples to Tiled rendering

multiple off-axis projections to render different sections of a scene. The results are assembled into one large image array to produce the final image. This is often necessary when the desired dimensions of the final rendering exceed the OpenGL implementation’s maximum viewport size.

Thanks Ken