[vtkusers] [python] vtkWin32OpenGLRenderWindow error when calling from thread vtkJPEGWriter.writer method

[Gustavo Serra Scalet]

Ok, I'll try to put all VTK stuff on the same thread and controlling from
another one, that should do

I'll post the results soon... thx already

2007/11/19, David Cole <david.cole at kitware.com>:
>
> VTK objects are not safe for accessing from multiple threads
> simultaneously. Do all of your VTK object access from the same thread (or,
> alternatively, use your own locking mechanism to ensure that only one thread
> at a time may be accessing VTK objects)
>
> And if you have a render window (on Windows at least) the GUI thread must
> access VTK objects to respond to windows WM_ messages. So, generally, you
> need to restrict access to VTK objects to the same thread that your render
> window is responding to messages on...
>
>
>
> On 11/19/07, Gustavo Serra Scalet <gsscalet at gmail.com> wrote:
>
> > Hello to all,
> >
> > I'm trying to do a recording system that catches what is happening on
> > the interactor and writes to a file. It has to be a thread or else the
> > interactor will be unreachable while writing the movie. I've got the same
> > error when I simplified the problem to just get a jpeg screenshot of the
> > interactor when using threads. When I just call the method (
> > self.img.Write) I don't get this error msg and everything goes
> > perfectly. Can someone tell me what's wrong with my code?
> >
> >     def __init__(self, parent):
> >         from vtk import vtkConeSource, vtkPolyDataMapper, vtkActor,
> > vtkRenderer
> >         # creates a dumme Cone
> >         self.c = vtkConeSource()
> >         self.c.SetHeight(3)
> >         self.c.SetRadius(1)
> >         self.c.SetResolution(10)
> >         # creates a mapper with the cone
> >         self.m = vtkPolyDataMapper()
> >         self.m.SetInput(self.c.GetOutput())
> >         # sets the actor with the mapper
> >         self.a = vtkActor()
> >         self.a.SetMapper(map)
> >         self.a.SetPosition((0,0,0)) # middle of the screen
> >         # puts the actor inside the renderer
> >         self.r = vtkRenderer()
> >         self.r.SetBackground((0,0,0)) # black bg
> >         self.r.AddActor(self.a)
> >         self.r.GetActiveCamera().SetPosition((10,10,10)) # camera at
> > some position
> >
> >         # set the interactor with this renderer, attached to a wx panel
> >         from vtk.wx.wxVTKRenderWindowInteractor import
> > wxVTKRenderWindowInteractor
> >         self.i = wxVTKRenderWindowInteractor(self.panel , -1 , size =
> > self.panel.GetSize())
> >         self.i.GetRenderWindow().AddRenderer(self.r)
> >         self.i = interactor(self.r,self.panel)
> >
> >         # imaging filter
> >         from vtk import vtkWindowToImageFilter
> >         self.w2i = vtkWindowToImageFilter()
> >         self.w2i.SetInput(self.i.GetRenderWindow())
> >
> >         # the jpeg object
> >         from vtk import vtkJPEGWriter
> >         self.img = vtkJPEGWriter()
> >         self.img.SetQuality(80) # 80% is good
> >         self.img.SetInput(self.w2i.GetOutput())
> >         self.img.SetFileName('01.jpg')
> >
> >     def OnGetPictureButton(self, event):
> >         # threading the image writing
> >         from thread import start_new_thread
> >         start_new_thread(self.img.Write,()) # error
> >         # this way I don't get the error msg
> >         # self.img.Write()
> >         event.Skip()
> >
> > when "OnGetPictureButton" is called, I get this error on a pop up screen
> > from vtk:
> >
> > "ERROR: In ..\..\VTK-5.0]\Rendering\vtkWin32OpenGLRenderWindow.cxx, lin
> > vtkWin32OpenGLRenderWindow(02FE1640): wglMakeCurrent failed in Mak"
> >
> > Is it some lock issue?
> >
> > thx
> >
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>
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