textures in 3.0

Kenneth Wang kenwang at leland.Stanford.EDU
Tue Dec 7 14:36:08 EST 1999


Thanks to Charles Law for his reply to my last posting re: bypassing
in image filters.  I downloaded and built the nightly yesterday, and
bypassing seemed to work as expected.  Unfortunately, I encountered
some different problems with the nightly, now related to texture

Below is the pipeline I have used successfully with 2.4 for some time
to do simple textures of image planes.  Now, when I use this pipeline
with 3.0, I don't get a correctly mapped texture.  Instead, I get a
mostly solid-colored plane, with two very thin edges of what looks
like it could be my data squished against the two coordinate axes of
my plane (i.e. I think these two edges correspond to the lines from
the vtkTextureMapToPlane's origin to its point1 and point2).

This seems to be an obvious indication of something I'm now doing
wrong in my texture coordinate generation, but I don't know what that
might be.  Have there been important changes to texture coordinates in
moving from 2.4 to 3.0?


	|			      |
vtkThresholdPoints 		vtkExtractVOI
	|			      |
       ...			vtkTexture <------ vtkLookupTable
  data seems OK			      |
vtkPlaneSource  vtkTransform	      |
       |              |		      |
   vtkTransformPolyDataFilter	      |
           |			      |
   vtkTextureMapToPlane		      |
(same geometry as plane source)	      |
(specified w/ origin, pt1, pt2)	      |
           |			      |
   vtkCastToConcrete		      |
           |			      |
   vtkPolyDataMapper		      |
           |			      |
   vtkPolyDataActor <-----------------+
   texture does not show up
   as expected

Kenneth C. Wang			E-mail: kenwang at stanfordalumni.org
Electrical Engineering Dept.	Voice:  (650) 725-0458
Stanford University		Fax:    (650) 725-7731
CIS 214, Stanford, CA 94305	Web:    http://www.stanford.edu/~kenwang

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