Basically what I'm trying to do is as follows:

I have a software that generates and shows a pointcloud by analyzing Time-of-Flight data (Z-Data). This software has a GUI that delivers this pointcloud on a grid, and you can watch it and adjust the camera to change the perspective, or apply filtering to it and so on.

Since the Z-data was recorder through a stereoscopic system, I want to obtain a perspective transformation.

My idea was to simply change the position of the camera in the GUI and than add a button that sais (ex. New Perspective) that calls a function that would measure the distances from the existing pointcloud to the camera I'm viewing it from. Of course this would generate some occluded areas, but I want this to happen.

And now the main question is: How can I do that? Are there any functions in OpenGL that measure the distance from an object to a camera, or is it even possible to do something like his? Or has someone some other idea?

P.S. The software uses the qt sdk and opengl