[vtkusers] Light bug ... (Better explained)

[Sebastien Auclair]

Humm !

So is this a bug with VTK ?
No way to go around this ?
We are currently using VTK 4.0.



----- Original Message ----- 
From: "Nigel Nunn" <nNunn at ausport.gov.au>
To: <vtkusers at public.kitware.com>
Cc: <sxa at fluent.com>
Sent: Wednesday, April 23, 2003 11:51 AM
Subject: RE: [vtkusers] Light bug ... (Better explained)


> 
> Hi Sebastien, 
>  
> > As you can see in the "after.jpg" image, the red sphere 
> > doesn't seem to update the way its receiving light ! 
>  
> Thanks for so neatly illustrating the problem. I feel this may 
> be related to a lighting problem I wrote about earlier: images 
> rendered off-screen are not getting the same user-defined lights 
> currently applied to images rendered on-screen. 
>  
> One of the following may need adjustment: 
>  
>  1. our updating of time-stamps, or
>  2. the logic used for updating the lights 
>     in the low-level Render operations 
>  
> vtkRenderer::Render() makes a fairly complicated test of 
> when and what to "update".  If a call to Render() does in 
> fact trigger a call to DeviceRender(), then DeviceRender() 
> tries to get the lighting right.  I have not yet stepped 
> through a debug version to work out what needs to happen. 
>  
> Nigel 
>  
>  
> 
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