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<TITLE>Re: [vtkusers] Opacity of vtkActor2D</TITLE>
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<FONT SIZE="4"><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><BR>
Hello,<BR>
I don’t know much about the imagemapper and the image pipeline but from a GL perspective, it sounds like you have <BR>
a glTexEnv problem. Sounds like your image is being applied with DECAL mode (I think this is GL’s default mode).<BR>
<BR>
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<BR>
of rgba on your primative.<BR>
That said you’ll need to change the mode to something like MODULATE so that the fragment output will (basically) be the multiplication<BR>
of the underlying primative rgba values and the rgba values of the image (texture) at each fragment.<BR>
<BR>
If you can get your video source to a vtkTexture like so:<BR>
...<BR>
texture = vtkTexture<BR>
texture.setInputConnection( video.GetOuputPort())<BR>
texture.setBlendingMode( VTK_TEXTURE_BLENDING_MODE_MODULATE )<BR>
..<BR>
Then change your actor to a vtkTexturedActor2D<BR>
actor = vtkTexturedActor2D<BR>
actor.setTexture( texture );<BR>
...<BR>
<BR>
maybe that will do what you want.<BR>
Gerrick<BR>
<BR>
<BR>
On 7/11/08 10:07 AM, "dream_noir" <kyle.charbonneau@gmail.com> wrote:<BR>
<BR>
</SPAN></FONT></FONT><BLOCKQUOTE><FONT SIZE="4"><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Just to clarify here is a small example program that shows what I am trying to do: <BR>
from vtk import *<BR>
import time<BR>
<BR>
video = vtkVideoSource()<BR>
video.SetFrameRate(30)<BR>
video.SetFrameSize(640, 400, 1)<BR>
video.Record()<BR>
<BR>
mapper = vtkImageMapper()<BR>
mapper.SetInputConnection(video.GetOutputPort())<BR>
mapper.SetColorWindow(233)<BR>
mapper.SetColorLevel(138.5)<BR>
<BR>
actor = vtkActor2D()<BR>
actor.GetProperty().SetOpacity(0.3)<BR>
actor.SetMapper(mapper)<BR>
<BR>
cone = vtkConeSource()<BR>
cone.SetHeight( 3.0 )<BR>
cone.SetRadius( 1.0 )<BR>
cone.SetResolution( 10 )<BR>
<BR>
coneMapper = vtkPolyDataMapper()<BR>
coneMapper.SetInputConnection( cone.GetOutputPort() )<BR>
<BR>
coneActor = vtkActor()<BR>
coneActor.SetMapper( coneMapper )<BR>
<BR>
ren = vtkRenderer()<BR>
ren.AddActor2D(actor)<BR>
ren.AddActor(coneActor)<BR>
<BR>
renWind = vtkRenderWindow()<BR>
renWind.AddRenderer(ren)<BR>
<BR>
for i in range (0, 2000):<BR>
time.sleep(0.03)<BR>
renWind.Render()<BR>
You can't see the cone behind the video source despite setting the opacity. Any ideas? <BR>
</SPAN></FONT></FONT><BLOCKQUOTE><FONT SIZE="4"><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><B>dream_noir wrote:<BR>
</B>I have a vtkActor2D object .that I'm putting a video source in to display in my app. I add this actor to a renderer with the AddActor2D method. Now I want this Actor2D to be transparent so I can see the scene behind it. Unfortunately, using the GetProperty()/SetProperty() methods to get or set the Property2D object and change the opacity there does nothing. The video is still opaque and completely blocks the scene behind it. What can I do? Is this a bug or am I going about it wrong? <BR>
</SPAN></FONT></FONT></BLOCKQUOTE><FONT SIZE="4"><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><BR>
<HR ALIGN=LEFT SIZE="3" WIDTH="300">View this message in context: Re: Opacity of vtkActor2D <a href="http://www.nabble.com/Opacity-of-vtkActor2D-tp18385577p18405991.html"><http://www.nabble.com/Opacity-of-vtkActor2D-tp18385577p18405991.html></a> <BR>
Sent from the VTK - Users mailing list archive <a href="http://www.nabble.com/VTK---Users-f14274.html"><http://www.nabble.com/VTK---Users-f14274.html></a> at Nabble.com.<BR>
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