I've needed to run a recorded simulation offscreen and save it to a sequence of images, and the ScreenCaptureHandler seemed to be the simplest way to do that, and with this change it's possible.
Another change: I've also added the ability to specify continuous capture of all frames, or a certain number of frames. ScreenCaptureHandler now has a setFramesToCapture(int) method. The argument will be interpreted as:
0 : don't capture
<0 : capture continuously
>0 : capture that number of frames then stop
I also added startCapture() and stopCapture() methods so that user code can start capturing (either continuously or the given number of frames) at a given point in their program. setFramesToCapture() won't start capturing, you have to call startCapture() afterwards. The handler also now has another key to toggle continuous capture (defaults to 'C').
Note that continuous capture will of course only work if the CaptureOperation writes to different files (for example, a WriteToFile with SEQUENTIAL_NUMBER mode) or does something different each time... Otherwise it will just overwrite of course. :-)
I've also taken the chance to refactor the addCallbackToViewer() method a bit too, since finding the right camera is needed in two places now.
I've tested all cases (I think). If you want to try, in osgviewer.cpp and replace the line
// add the screen capture handler
viewer.addEventHandler(new osgViewer::ScreenCaptureHandler);
with
// add the screen capture handler
osgViewer::ScreenCaptureHandler* captureHandler = new
osgViewer::ScreenCaptureHandler(
new osgViewer::ScreenCaptureHandler::WriteToFile(
"screenshot", "jpg",
osgViewer::ScreenCaptureHandler::WriteToFile::SEQUENTIAL_NUMBER),
-1);
viewer.addEventHandler(captureHandler);
captureHandler->startCapture();
And vary the "-1" (put 0, 10, 50) and then use the 'c' and 'C' keys and see how it reacts.
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