How to modify the video output to external monitor


This is my first post to the forum, I have never used OpenGL or done graphics programming before. I hope you guys can help…

I want to be able to connect an external display to my Windows PC (in addition to the existing one), and stream a selected portion of the screen to this display. For example, if I have a small terminal window open on my main monitor, then this smaller display will show only that terminal window, not the rest of my desktop. I guess it’s like Picture
In Picture (PIP) on a TV, but for a PC instead.

I envisage a software application that allows me to select a portion of my main desktop, maybe using a rectangle tool to select a part of my screen to be displayed on the external monitor. Does anybody know if such an application exists?

I don’t mind getting into the programming side of it (maybe using DirectShow or OpenGL), but some pre-made software would be ideal, to get this working quickly. If not, can anyone recommend how I would begin coding this in OpenGL?

Many thanks for your help.



Bump…has anyone got any ideas for this?

Many thanks,


That is something that is managed by the video driver. You can either extend a desktop or duplicate what you have on first monitor also on the second monitor.

Just position your window on the second monitor and create your GL context and render to your window.