[vtkusers] vtkCSCS PointSpriteMapper integration

[Alex]

Hello everyone,

I manage to solve this issue, thanks to Stephane Ploix who hinted that  
I should look at the clipping planes value. Then I've fallen upon an  
old post http://marc.info/?l=vtkusers&m=119419575541727&w=2 (involving  
John Biddiscombe, the author of the PointSpriteMapper) and found the  
NearClippingPlaneTolerance attribute in vtkRenderer.

Setting this value at 0.1 fix the problem. I suppose that a short near  
clipping value induces some precision error in the ray-casting  
computation.

Best regards,

---
Alex Tek
Laboratoire de Biochimie Théorique - UPR9080 CNRS
Institut de Biologie Physico-Chimique
13, rue Pierre et Marie Curie 75005 Paris
alex.tek at ibpc.fr

Le 12 juil. 10 à 17:37, Alex a écrit :

> Hello,
> 	
> I use vtkPointSpriteMapper to display scattered points as spheres.
> When I use the ExactSphere shader program I get some weird artifacts  
> when the camera zoom in or rotates :   http://alex.tek.free.fr/these/exactSphere_weird.jpg
>
> I say weird because the example programs of the vtkCSCS package are  
> working well.
>
> Do you have any clue of what could happen ?
>
> I'm on MacOS X 10.5.8. It is a Cocoa based application
>
> Best regards,
>
> Alex
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