[vtkusers] Animation Conundrum

[Bruno da Silva de Oliveira]

Hi Charlie,

The keyword "global" is only needed when you have to specifically 
identify a global variable for binding purposes (ie, "x = 1"). If you're 
only accessing, you don't need it, since Python supports nested scopes.

Regards,

Charlie Moad wrote:

>This may not help, but python is picky with the vtk threads.  I
>suggest using the "global" keyword in your callback.  I have found it
>helps with callbacks in vtk.
>
>def myCallback():
>    global jpgReader, atext, renWin
>    .....
>
>
>On 10/7/05, Mischa Thesberg <mejthesb at swri.ca> wrote:
>  
>
>>Are you suggesting a code that is something like this?:
>>
>>        def myCallback():
>>            for i in range(100,260):
>>                #time.sleep(0.03)
>>                givable = "C:/Conics/1-32-04/9-28-2005 1-32-04 PM-0%d" %
>>i+".jpg"
>>                jpgReader.SetFileName(givable)
>>                atext.SetInput(jpgReader.GetOutput())
>>                renWin.Render()
>>
>>        ren.AddActor(triangulation)
>>        ren.SetBackground(1, 1, 1)
>>        renWin.SetSize(350, 350)
>>        iren.AddObserver("TimerEvent", myCallback)
>>        iren.Initialize()
>>        iren.Start()
>>        t = threading.Timer(0.1,myCallback) # call animate after 0.1 seconds
>>        t.start()
>>
>>when this code runs I get the following error from the prompt
>>
>>ERROR: In \OCCIviewerSDK\Vtk42\Rendering\vtkWin32OpenGLRenderWindow.cxx,
>>line 22
>>8
>>vtkWin32OpenGLRenderWindow (00B290B0): wglMakeCurrent failed in
>>MakeCurrent(), e
>>rror: The requested resource is in use.
>>
>>which seems to me to be a share renderer problem.  Or is my code using
>>the wrong idea?  Thank you for your help btw
>>
>>
>>Bruno da Silva de Oliveira wrote:
>>
>>    
>>
>>>Hi Mischa,
>>>
>>>Try to use a timer. Connect an observer in the RenderWindowInteractor
>>>listening for the TimerEvent, and in this handler change the texture.
>>>
>>>HTH,
>>>
>>>Mischa Thesberg wrote:
>>>
>>>      
>>>
>>>>   This is the same problem I was having before however I still
>>>>cannot seem to fine a solution to it.  I am simulating the effect of
>>>>projecting a movie onto a cone by creating a cone object in a render
>>>>window (with an interactor) and changing the texture (mapped using
>>>>textureMapToPlane) of the cone about 10 times a second (in other
>>>>words I loop through a series of sequentially named jpeg's).  The
>>>>problem is that while this animation is occuring (which is always)
>>>>the interactor is frozen with an hourglass (or if I put the animation
>>>>in a rudimentary thread the hourglass is gone but I still can't
>>>>interact).  How do I keep the interactor usable as I constantly
>>>>change the texture of the cone.  I think a problem with the way I
>>>>tried to thread has to do with the shared resources between the actor
>>>>changing textures and the interactor.  If someone could give me some
>>>>advice it would be much appreciated.  If threading is in fact
>>>>necessary it would be helpful to have a code snippet or a link to an
>>>>explicit example.  The pertinent part of my code is below (I have
>>>>kept all of the commented out stuff just to illustrate the type of
>>>>stuff I've tried:
>>>>
>>>>       #def myCallback():
>>>>         #  if renWin.GetEventPending():
>>>>           #    renWin.SetAbortRender=1
>>>>
>>>># Add the actors to the renderer, set the background and size
>>>>       ren.AddActor(triangulation)
>>>>       ren.SetBackground(1, 1, 1)
>>>>       #ren.AddObserver("StartEvent", myCallback)
>>>>       renWin.SetSize(350, 350)
>>>>       #renWin.FullScreenOn()
>>>>       #iren.UpdateSize(700,700)
>>>>       #iren.AddObserver("InteractionEvent", myCallback)
>>>>       iren.Initialize()
>>>>
>>>>       #renWin.Render()
>>>>       iren.Start()
>>>>
>>>>       for i in range(100,260):
>>>>           time.sleep(0.03)
>>>>           #iren.UnRegister(renWin)
>>>>           #iren = None
>>>>           #iren = vtk.vtkRenderWindowInteractor()
>>>>           givable = "C:/Conics/1-32-04/9-28-2005 1-32-04 PM-0%d" %
>>>>i+".jpg"
>>>>           jpgReader.SetFileName(givable)
>>>>           atext.SetInput(jpgReader.GetOutput())
>>>>           #atext.Render(ren)
>>>>           #ren.Render()
>>>>           renWin.Render()
>>>>           #print iren.GetInitialized()
>>>>           #iren.SetRenderWindow(renWin)
>>>>           #iren.Enable()
>>>>           #iren.Initialize()
>>>>           #iren.Start()
>>>>
>>>>
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>>>>
>>>>        
>>>>
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>>
>>    
>>
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>
>  
>

-- 
Bruno da Silva de Oliveira
bruno at esss.com.br
ESSS - Engineering Simulation and Scientific Software
http://www.esss.com.br