Using OpenGL to write to an image file

Question

I'm just curious if there is a way to use OpenGL to write pixel data to an external JPEG/PNG/some other image file type (and also create an image to write the data to if one does not already exist). I couldn't really find anything on the subject. My program doesn't really make use of openGL at all otherwise, I just need something that can write out images.

Answer 1

Every image "put into" or "taken from" OpenGL is in a rather raw pixel format. OpenGL does neither have functionality for file I/O nor for handling of sophisticated image formats like eg BMP, JPEG or PNG, as that is completely out of its scope. So you will have to look for a different library to manage that and if this was the only reason you considered OpenGL, then you don't need it at all.

A very simple and easy to use one (and with an interface similar to OpenGL) would be DevIL . But many other larger frameworks for more complex tasks, like Qt (GUI and OS) or OpenCV (image processing) have functionality for image loading and saving. And last but not least many of the individual formats, like JPEG or PNG usually also have small official open-source libraries for handling their respective files.