[vtkusers] How implement other ligtning model in VTK

Lisa Avila lisa.avila at kitware.com
Wed Jul 23 09:23:33 EDT 2003

Hello Robert / Rob,

It is true that OpenGL is used for geometric rendering and lighting in VTK 
- but the lighting for volume rendering (except for the VolumePro mappers) 
is done in software. You can look at vtkEncodedGradientShader for how the 
lighting is done - it is set up to match OpenGL lighting so that if you had 
an isosurface volume rendered and a isosurface geometrically rendered they 
should look (mostly) the same. To change the sampling process you would 
create a new subclass of vtkVolumeRayCastFunction.


At 03:11 AM 7/23/2003, Robert Belleman wrote:
>Lighting and rendering is done by OpenGL, not by Vtk.
>If you want to implement a new lighting model you would
>have to do this in OpenGL. For details on the lighting
>model used in OpenGL, see "the red book":
>OpenGL Programming Guide, Mason Woo, Jackie Neider
>and Tom Davis, Addison-Wesley.
>-- Rob
>Robert Le¶nik wrote:
>>I'm student and I have to implement Sakas lightning model for gaseous
>>phenomena. Because I'm quite new in VTK, I want to ask few questions:
>>- Which objects in VTK response for ray casting process? What is role every
>>of them?
>>- How the rendering process is done? (not generally, but in details)
>>- Which object can I modify or inherit from in order to change the sampling
>>method in ray casting process, or to change the lightning model?
>>Thanks for help and excuse for my English
>>rlesnik at hoga.pl
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