elliotwoods/ofxGrabCam — pull request #5 by elliotwoods (2012-05-17 11:39:27+00:00)
Title: Feature trackball

@roymacdonald - here i've changed the rotation to use a trackball mechanism rather than simple rotation. you'd need to disable `setFixUpwards` to get the proper peronality (i.e. press 'u' in the example)

could you check it out and see if it gives the action you wanted
i did some tests with 'arcball' maths, but it doesn't work well when you always start the rotation from the centre of the arcball, common issues are :

1. Radius of arcball is too big (you always start the action in the centre, and must allow user to travel to opposite edge of screen)
2. It's impossible to get the z-axis rotations without already destroying the rotation you already have

trackball is essentially the same maths, but in a finite difference model where mouse dx,dy are acting on start x, start y

possibility of a 'hold hotkey to roll'

also to @kylemcdonald - anything else i could improve on this?