[vtkusers] Opacity of vtkActor2D

[dream_noir]

Thank you for your reply. Unfortunately I haven't been able to apply your
advice and get things to work correctly. I've looked over vtkTexture and
vtkTexturedActor2D class but just can't figure out how to get them to play a
video stream. I have access to some code that does something similar to what
I want and from looking it over it seems you are definitely on the right
track using a texture. Unfortunately the code uses pure c++/opengl and not
vtk classes.

Any ideas are appreciated. Thanks.



Hello,
I don¹t know much about the imagemapper and the image pipeline but from a GL
perspective, it sounds like you have
 a glTexEnv problem. Sounds like your image is being applied with DECAL mode
(I think this is GL¹s default mode).

This basically means that the rgb value in your image (texture in GL speak)
is being used for the output fragment color an ignoring the values
 of rgba on your primative.
 That said you¹ll need to change the mode to something like MODULATE so that
the fragment output will (basically) be the multiplication
 of the underlying primative rgba values and the rgba values of the image
(texture) at each fragment.

If you can get your video source to a vtkTexture like so:
...
   texture = vtkTexture
   texture.setInputConnection( video.GetOuputPort())
   texture.setBlendingMode(     VTK_TEXTURE_BLENDING_MODE_MODULATE )
..
Then change your actor to a vtkTexturedActor2D
   actor = vtkTexturedActor2D
   actor.setTexture( texture );
...
 
 maybe that will do what you want.
Gerrick
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