[vtkusers] vtkScalarBarActor color changes

[David.Pont at ForestResearch.co.nz]

It seems using texture can corrupt a scalar bar. I have made a simple C++
test program to illustrate the problem.
Are there any C++ vtkers that are willing to try this? I am running vtk
3.1.0 so I suppose the first question is: does this problem still exist in
the current vtk? It could also be a hardware problem on my end?
Attached are: 1- C++ source file, 2- image illustrating problem (happy
scalar bars on the left, sad scalar bars on the right).
See notes at top of source file on how to run the four tests.

   regards
    Dave Pont

(See attached file: ptms.cpp)(See attached file: ptms_3.1.0.jpg)


|---------+------------------------------->
|         |           David.Pont at forestres|
|         |           earch.co.nz         |
|         |           Sent by:            |
|         |           vtkusers-admin at vtk.o|
|         |           rg                  |
|         |                               |
|         |                               |
|         |           06/11/2003 13:01    |
|         |                               |
|---------+------------------------------->
  >--------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                                |
  |       To:       vtkusers at vtk.org                                                                                               |
  |       cc:                                                                                                                      |
  |       Subject:  [vtkusers] vtkScalarBarActor color changes                                                                     |
  >--------------------------------------------------------------------------------------------------------------------------------|




I am getting changes in coloration of my scalar bar. The colors initially
appear incorrect. If I zoom in on my main actor (so it is significantly
larger than the window) the scalar bar colours suddenly change to appear
correctly, but revert when I zoom back out.
At exactly the same zoom at which the colors change from incorrect to
correct a small actor (vtkPlaneSource, dimensions 1,1,0, origin 0,0,0)
appears.
Put another way: the actor is visible when the scalar bar colors are
correct; the actor is not visible when the colors are incorrect.
For the main actor dimensions are approx. 120,120,0 and origin 0,0,0
I am wondering if the fact that all actors have a z dimension of 0 has
something to do with it?
If I rotate the geometry the scalar bar colors flicker and change
intermittently!

I have tried calling vtkRenderer->ResetCameraClippingRange but this had no
effect.

I have run out of ideas... by the way I am still working with vtkVersion
3.1.0
I am actually using a texture applied to the main actor, which might have
something to do with it (i have not had this problem when I do not use
texture).
My current guess is something happening during rendering (a conflict around
actor bounds, clipping, polygon shading, texturing...).

   can anyone shed any light on this ?
   Dave Pont


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