MantisBT - ParaView
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IDProjectCategoryView StatusDate SubmittedLast Update
0010406ParaViewBugpublic2010-03-10 20:292010-03-23 22:00
ReporterAlan Scott 
Assigned ToKen Moreland 
PrioritynormalSeverityminorReproducibilityalways
StatusclosedResolutionno change required 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
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Topic Name
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Summary0010406: TextureMapToSphere prevent seam is wrong
DescriptionAs per Greenfield, our TextureMapToSphere "Prevent Seam" is wrong. What it tries to do is draw the texture on the sphere twice. What it should do is draw the texture on the sphere, then CONTINUE to draw it one more time around. That way, if there are minor holes, the second draw of the texture will catch it.

A good test texture is here: Use the world map, found at http://www.oera.net/How2/PlanetTexs/EarthMap_2500x1250.jpg [^]
Steps To Reproduce
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Attached Filespng gradientimage.png (50,188) 2010-03-11 09:16
https://www.vtk.org/Bug/file/7957/gradientimage.png
png

png gradientmapped.png (88,943) 2010-03-11 09:17
https://www.vtk.org/Bug/file/7958/gradientmapped.png
png
Issue History
Date ModifiedUsernameFieldChange
2010-03-10 20:29Alan ScottNew Issue
2010-03-11 09:16Ken MorelandFile Added: gradientimage.png
2010-03-11 09:17Ken MorelandFile Added: gradientmapped.png
2010-03-11 09:21Ken MorelandNote Added: 0019839
2010-03-11 09:21Ken MorelandStatusbacklog => @80@
2010-03-11 09:21Ken MorelandResolutionopen => no change required
2010-03-11 09:21Ken MorelandAssigned To => Ken Moreland
2010-03-23 22:00Alan ScottNote Added: 0019997
2010-03-23 22:00Alan ScottStatus@80@ => closed

Notes
(0019839)
Ken Moreland   
2010-03-11 09:21   
I do not really understand the description of how the prevent seam should work, but I can see nothing wrong with the current implementation. The current implementation pastes the image on one side and then pastes the mirror image on the other. The intention is that the left of the image abuts itself and likewise for the right. You cannot have the left image touch the right in the texture. Even if they did match up on the image, the texture mapping hardware does not allow this discontinuity.

The world map you are using is not a good test case for looking at the prevent seam feature. It's left and right sides match up, which is not always the case. I have attached a test gradient image to this bug that does not have its left and right (or top and bottom) match up. Notice that when you use the prevent seam option, there really is no seam in the texture mapping (an image of this is also attached).
(0019997)
Alan Scott   
2010-03-23 22:00   
OK, I get it. Closing this one.