[Octave-bug-tracker] [bug #48873] Matlab incompatibilities in plot routines revealed through dump_plot_demos

[Markus Mützel]

Follow-up Comment #2, bug #48873 (project octave):

To be honest, I do not understand what Matlab is doing. According to [1], I
think we are doing the correct thing.
If I understand the following sentences correctly, it should not matter in
which direction the surface normals are pointed when "BackFaceLighting" is set
to "reverselit":

Face lighting when the vertex normals point away from camera, specified as one
of these values:
'reverselit' — Light the face as if the vertex normal pointed towards the
camera.


This is what is done in Octave: Normals pointing away from the camera are
reversed.

Additionally, I cannot see any visual difference between "lit" and "unlit" in
Matlab [2]. According to [1], there should be a difference:

'unlit' — Do not light the face.
'lit' — Light the face according to the vertex normal.


Those short sentences seemed easy enough to understand correctly when I first
read them. I might have misunderstood them anyway. Can someone help me out,
what else could be meant?

[1]
http://de.mathworks.com/help/matlab/ref/primitivesurface-properties.html#property_backfacelighting
[2] http://josoansi.de/octave_plot_compare/compare_plot_demos_04.html#light_08

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