[vtkusers] Where is vtkVolumeRayCastMIPFunction::CastRay called from?

[Wolfram H Volpi]

Does any one know where vtkVolumeRayCastMIPFunction::CastRay is called
from?

The in-line documentation says:
// This is called from RenderAnImage (in vtkDepthPARCMapper.cxx)

Where is vtkDepthPARCMapper.cxx?  I can not find it.

Thanks for your help,
Wolfv.