The Persistence of Vision Raytracer (POV-Ray).

This is the legacy Bug Tracking System for the POV-Ray project. Bugs listed here are being migrated to our github issue tracker. Please refer to that for new reports or updates to existing ones on this system.


FS#61 - Dispersion does not give proper results

Attached to Project: POV-Ray
Opened by Christoph Lipka (clipka) - Saturday, 24 October 2009, 15:16 GMT
Last edited by Christoph Lipka (clipka) - Monday, 22 March 2010, 15:03 GMT
Task Type Definite Bug
Category Backend → Other
Status Closed
Assigned To Christoph Lipka (clipka)
Operating System All
Severity Medium
Priority High
Reported Version 3.70 beta 34
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 1
Private No


Source code inspection during examination of issues with the scene published at http://povray.sitewww.ch/?p=177 show the following issues with current (beta.34) implementation of dispersion in POV-Ray 3.7:

  • The same adjustment to the IOR that is applied at the very first dispersion interface is erroneously applied to all subsequent interfaces.
  • As an exception, dispersion adjustment is erroneously not applied to any interface defined by the surface of a non-dispersing object embedded into a dispersing object.

While this still allows to use dispersion for artistic effect, it is neither physically realistic, nor does it match 3.6 behavior.

This task depends upon

Closed by  Christoph Lipka (clipka)
Monday, 22 March 2010, 15:03 GMT
Reason for closing:  Fixed
Additional comments about closing:  residual minor issues with change #4895 do not pertain to this bug report
Comment by Christoph Lipka (clipka) - Sunday, 25 October 2009, 19:32 GMT
  • Field changed: Status (Investigating → Requires testing)
  • Field changed: Percent Complete (70% → 100%)
  • Task reassigned to Chris Cason (chrisc)

fixed with change #4895

Comment by Christoph Lipka (clipka) - Friday, 30 October 2009, 20:26 GMT

Note that change #4895 adds two new source files; they have been added to the Visual Studio projects, but not to the Linux makefiles yet.

Comment by Christoph Lipka (clipka) - Saturday, 07 November 2009, 16:19 GMT
  • Field changed: Reported Version (3.70 beta 32 → 3.70 beta 34)
  • Field changed: Percent Complete (100% → 90%)
  • Task reassigned to Christoph Lipka (clipka)

Minor issues still open regarding interpolation of the dispersion colors table, in order to improve high-dispersion-count results.