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IDProjectCategoryView StatusDate SubmittedLast Update
0006444VTK(No Category)public2008-02-26 09:142016-08-12 09:54
ReporterChris Kruszynski 
Assigned ToKitware Robot 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
Summary0006444: vtkOpenGLExtensionManager performs undesired Render when vtkRenderWindowInteractor::Initialize() is called
DescriptionvtkOpenGLExtensionManager r1.31 calls vtkRenderWindow::Render() at line 399 if vtkRenderWindow::GetNeverRendered() returns 1 at line 397.

This results in vtkRenderWindow::Render() being called from the middle of vtkOpenGLRenderWindow::OpenGLInit() with some of the settings which are set in this function still disabled, most notably GL_NORMALIZE. This in turn results in wrong rendering results during the first render after program start, which are very noticeable in some circumstances. See the attached image, on the left what it should look like, and on the right what it actually looks like.

The issue only happens when vtkRenderWindowInteractor::Start() (or Initialize()) is called, and only on the first render pass, thus on any next render pass (such as after any interaction) the image is as it should be. When vtkRenderWindow::Render() is called the issue does not happen, because vtkRenderWindow::Render sets NeverRendered to 0 before any initialization, thus before OpenGLInit() gets called.
Additional InformationThis probably only matters in strange circumstances, nevertheless it does happen.

The extension manager should probably not call Render at all, since the manager works just as well when the RenderWindow has not yet actually ever rendered anything in spite of the NeverRendered ivar being set to 0. This happens when vtkRenderWindow::Render() is called - the ivar is 0 but no rendering has yet happened when the manager checks this ivar when it is created in OpenGLInit)).
TagsNo tags attached.
Attached Filespng file icon example.png [^] (2,434 bytes) 2008-02-26 09:14

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-  Notes
Kitware Robot (administrator)
2016-08-12 09:54

Resolving issue as `moved`.

This issue tracker is no longer used. Further discussion of this issue may take place in the current VTK Issues page linked in the banner at the top of this page.

- Issue History
Date Modified Username Field Change
2008-02-26 09:14 Chris Kruszynski New Issue
2008-02-26 09:14 Chris Kruszynski File Added: example.png
2011-06-16 13:11 Zack Galbreath Category => (No Category)
2016-08-12 09:54 Kitware Robot Note Added: 0036953
2016-08-12 09:54 Kitware Robot Status expired => closed
2016-08-12 09:54 Kitware Robot Resolution open => moved
2016-08-12 09:54 Kitware Robot Assigned To => Kitware Robot

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