[vtkusers] alpha transparency: image to texture

[David Gobbi]

Hi Jan,

You end up with a 6-component image, because vtkWindowToImageFilter
always extracts an RGB bitmap.  Take a look at vtkCompositeFilter.

 - David

On Thu, 19 Apr 2001, Jan Vittrup Hansen wrote:

> Hi,
>
>   I need to map some monochrome texturemaps with the output from a rendering
> of a sphere. This I've managed to do by straight application of the
> vtkWindowToImageFilter. Only the background is included in the texturemap,
> where I'd much rather have transparency. Naively I tried the following approach
> only to get a core dump when I try to render using the map - am I missing
> something? (btw: I try to create a monochrome image with alpha transparency -
> i.e. 2 bytes per pixel)
>
>  Regards, Jan...
> ...
>     filter = vtkWindowToImageFilter()
>     filter.SetInput(renderWindow)
>
>     image = vtkImageAppendComponents()
>     image.SetInput1(filter.GetOutput())
>     image.SetInput2(filter.GetOutput())
>
>     return image.GetOutput()
> ...
>
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