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Dear Mark,<br>I'd really appreciate if you send more detailed information.<br><br>I can't figure out how to make a vtkRenderWindowInteractor receive AnimationCueTickEvents. I did add an observer, but from browsing the sources it seems that vtkRenderWindowInteractor does not event make an attempt to handle AnimationCueTickEvents.<br><br>The story is a different one, if I make a vtkAnimationCue observe AnimationCueTickEvents. Those events are perfectly handled, but the interactivity is lost. Could you make clear, possibly with a code example, what you meant by adding an observer to vtkRenderWindowInteractor to handle AnimationCueTickEvents?<br><br>Regards,<br>Guido<br><br>> Date: Thu, 10 Sep 2009 17:06:39 +0100<br>> Subject: Re: [vtkusers] Animation without polling?<br>> From: mark.gooding@gmail.com<br>> To: guidorodriguez1952@hotmail.com<br>> CC: vtkusers@vtk.org<br>> <br>> you shouldn't have to write a complete vtkRenderWindowInteractor, just<br>> add an observe to handle AnimationCueTickEvents<br>> <br>> http://www.vtk.org/doc/nightly/html/classvtkCommand.html<br>> <br>> i'll try to send you more detailed information later. I don't have my<br>> software which did animation to hand right now.<br>> <br>> Mark<br>> <br>> <br>> 2009/9/10 Guido Rodriguez <guidorodriguez1952@hotmail.com>:<br>> > Dear VTK users/developers,<br>> > I ask for guidance, how animated visualization is done right with VTK. What<br>> > I have in mind is an application which calculates, let's say, a temperature<br>> > field, which changes in time. Whenever the field is completely calculated<br>> > for the next time step, the visualization should be updated. In parallel,<br>> > the user should be able to work with the mouse/key controls to rotate the<br>> > view, zoom, interact with 3D widgets, etc.<br>> ><br>> > The obvious way would be to run VTK in one thread, and the calculation in<br>> > another. Each finished calculation step would notify VTK to update. But it<br>> > doesn't work like this. At least not with the X windows system. When I call<br>> > some pipeline's Update() function from a different thread, I get an "invalid<br>> > thread access".<br>> ><br>> > Next attempt. I implement an event buffer, which is written to by the<br>> > calculation thread, and which is read from by the VTK thread. This works<br>> > like a charm. Now VTK can check whether an update is necessary and get the<br>> > required data from the event buffer. But _when_ does VTK check for updates?<br>> > I can't seem to find a solution which sets VTK to sleep until either a<br>> > mouse/key event happens or until the calculation thread releases some lock,<br>> > simply because any VTK callback waiting for notification from a different<br>> > thread would stop VTK from reacting to mouse/key events during this period.<br>> ><br>> > The only solution I can see is to add a timer event like every 10 ms, which<br>> > checks the event buffer for updates. This works, but is it recommended?<br>> > Threading libraries have introduced locks and notification to avoid the<br>> > overhead from polling at interactive rates for events that may occur only<br>> > every few seconds. How can good multithreading programming styles be applied<br>> > to VTK?<br>> ><br>> > I hope the problem is clear. Can a different thread trigger pipeline updates<br>> > under X windows? Or do I have to write my own vtkRenderWindowInteractor?<br>> ><br>> > Regards,<br>> > Guido<br>> > ________________________________<br>> > With Windows Live, you can organize, edit, and share your photos.<br>> > _______________________________________________<br>> > Powered by www.kitware.com<br>> ><br>> > Visit other Kitware open-source projects at<br>> > http://www.kitware.com/opensource/opensource.html<br>> ><br>> > Please keep messages on-topic and check the VTK FAQ at:<br>> > http://www.vtk.org/Wiki/VTK_FAQ<br>> ><br>> > Follow this link to subscribe/unsubscribe:<br>> > http://www.vtk.org/mailman/listinfo/vtkusers<br>> ><br>> ><br><br /><hr />Share your memories online with anyone you want <a href='http://www.microsoft.com/middleeast/windows/windowslive/products/photos-share.aspx?tab=1' target='_new'>anyone you want.</a></body>
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