Dear Robert, Thank you very much for your answer. I'll manually move the object along the line by using the time between frames to compute speed and location then. Best, Dat
On Fri, Dec 3, 2010 at 3:13 AM, Robert Osfield <[email protected]> wrote: > Hi Dat, > > The AnimationPath assumes a constant speed between each control point > and animates accordingly. > > I guess it shouldn't be be possible to come up with the maths so that > one assumes a constant acceleration between control points and then > integrates to get the actual position at a given time. One would also > need to store the speed at the control point as the position, rotation > and scale. > > I'm not really familiar with osgAnimation yet, perhaps it provides > support for what you are after. > > Robert. > > On Fri, Dec 3, 2010 at 12:44 AM, Nguyen Tien Dat <[email protected]> wrote: >> Dear all, >> I need to move an object along a line with the speed of 1m/s. The >> object starts from stationary (0m/s). I use AnimationPath like this: >> >> osg::AnimationPath* animationPath = new osg::AnimationPath; >> animationPath->setLoopMode(osg::AnimationPath::NO_LOOPING); >> >> osg::Vec3 startPoint(startMat(3,0), startMat(3,1), >> startMat(3,2)); >> animationPath->insert(0.0,osg::AnimationPath::ControlPoint(startPoint >> , rotation)); >> >> osg::Vec3 endPoint(endMat(3,0), endMat(3,1), endMat(3,2)); >> >> float speed = 1.0; // (m/s) >> float timeOfAnimation = >> distanceFromStartPointToEndPoint/speed; >> >> >> animationPath->insert(timeOfAnimation,osg::AnimationPath::ControlPoint(endPoint >> , rotation)); >> >> matTransNode.setUpdateCallback(new >> osg::AnimationPathCallback(animationPath)); >> >> The animation works, but it seems to me that the speed instantly >> becomes 1m/s and there's no acceleration. So my question is: is there >> a way I can specify that, say, in the first second the acceleration is >> +1 m/s^2, and the next few seconds the acceleration is 0 m/s^2 (so >> that the speed is constant), and then in the last second the >> acceleration is -1 m/s^2? >> >> Thank you very much for your help. >> Best, >> Dat >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > -- Dat Tien Nguyen PhD Candidate, Computer Science Department The University of Iowa http://cs.uiowa.edu/~tinguyen _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
