[vtkusers] vtkTextureMapToSphere and PreventSeamOff not working as expected

[Alexander Pletzer]

Hi,

I'm trying to wrap the simple attached image around a sphere using 
vtkTextureMapToSphere and got some unexpected result -- the word 
"center" appears twice. Also the blue line is completely absent. There 
also appears to be a small gap at longitude 0 (see testOne.png). It 
looks as if the texture file was used twice.

Does anyone know hoe to fix this? After some googling I found that some 
people had to write a custom vtkTextureMapToSphere class to deal with 
this problem. I'd like the texture to completely cover the sphere, each 
of the "nw", "sw", "se", "ne", and "center" texts should only appear 
once, each of the red, blue, white, and green should also appear only once.

Thanks in advance.

--Alex


import vtk
import sys

filename1 = "one.png"

# Create a render window
ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
renWin.SetSize(480,480)
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

# Generate a sphere polydata
sphere1 = vtk.vtkSphereSource()
sphere1.SetThetaResolution(12)
sphere1.SetPhiResolution(12)
sphere1.SetStartTheta(0)
sphere1.SetEndTheta(360)

# Read the image data from  file
reader1 = vtk.vtkPNGReader()
reader1.SetFileName(filename1)

# Create texture object
texture1 = vtk.vtkTexture()
texture1.SetInputConnection(reader1.GetOutputPort())

# Map texture coordinates
map_to_sphere1 = vtk.vtkTextureMapToSphere()
map_to_sphere1.SetInputConnection(sphere1.GetOutputPort())
map_to_sphere1.PreventSeamOff()

# Create mapper and set the mapped texture as input
mapper1 = vtk.vtkPolyDataMapper()
mapper1.SetInputConnection(map_to_sphere1.GetOutputPort())

# Create actor and set the mapper and the texture
actor1 = vtk.vtkActor()
actor1.SetMapper(mapper1)
actor1.SetTexture(texture1)

ren.AddActor(actor1)

iren.Initialize()
renWin.Render()
iren.Start()

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