render to screen and file

Hi there all you smart and experienced GL people.

I have something that aspires to be a kind of a simulator for microbiology purposes. I have been doing it for many months now, and I need some nice and smooth way to export what’s going on the screen to a series of images. I guess you know the idea, I run the thing, the application does some fancy calculations and displays animated 3d objects as the result. I want to be able to see what’s going on (and interact) and store a percent of all frames to files. I would be thankful for pointing me the direction how to bite this problem.

You can store the rendered mage in a file by reading back the draw buffer (via glReadPixels) and storing it in a suitable format. maybe you should formulate your question more preciselly, I didn’t really understand what do you want.

OK, sorry for my messy text. The idea is to be able to render to screen and the same frame render to file. The purpose is to generate a sequence of images or a video afterwards. So glReadPixels (I used it once, years ago :wink: ), but is there any alternative? Or this is the optimal solution?

Well, it will be slow… But it is the easiest way. You could also use the PBO extension to speed up the readback, read this :…e_Transfers.pdf

Thanks for the tip.

Why not use Fraps that saves videos out of any OpenGL program!?

I use it for creating my own videos out of my apps.

You don’t have to program a single line, it just attaches to your program and you can save screenshots and videos.

You can find a free trial version on google.