Re: basic implementation for isosurface, isocolors, isonormals

[Martin Helm]

> On Mon, Mar 09, 2009 at 08:33:06PM +0100, address@hidden wrote:
> > On Mon, Mar 09, 2009 at 05:34:29PM +0100, Martin Helm wrote:
> > > in principle gnuplot can do it. But I cannot oversee how it fits into
> > > the octave drawing functions at the moment (I need to look into the
> > > code later, I have no access to octave now). The difference between 2d
> > > and 3d patches with gnuplot is that it is not possible to use the same
> > > syntax (2d uses a filled curve style which does not exist for 3d).
> >
> > I have a changeset that partly works to implement 3d triangular patches.
> > Give me a few hours and I'll send it
>
> Ok the attached patch against the tip adds triaangular 3D patches. Its
> not optimal as each patch is drawn individually, and that should be
> rewritten, but the example from isosurface works.. The patch will need a
> bit more work before commiting it including
>
> * Document new functions in plot.txi and NEWS
> * Style fixes in the added functions
> * isosurface called with no args doesn't yet plot as expected.
>
> In any case its a start and should allow isosurface and trisurf to be
> written.
>
> D.

Sorry for the late followup.
I changed the iso* functions and the helper functions a little bit (avoiding 
assignments of the form [] = [], which can lead to trouble otherwise) and 
tried to adjust the style to be more compliant with what I can see in the 
contribution section of the octave manual. I am pretty sure that there are 
further changes to the style to be done. 
The patches include the changes to plot/Makefile.in and add the new functions
isosurface, isocolors, isonormals, __interp_cube__ and __marching_cube__.
Thanks to Thomas Treichl who helps with the documentation and examples for the 
functions.
I made the patch from scratch not against your patch. I do not know if this is 
ok or not.
Please tell me how to proceede in the correct way.
With the new __go_draw_axes__ (gnuplot backend) I first ran into trouble 
because I use gnuplot 4.3 and this has the transparency feature which screws 
up the commands sent to gnuplot.
With 4.2 it works with some side effects and without coloring 
(FaceVertexCData). It seems to me that something like
unset hidden3d
set pm3d
set pm3d depthorder hidden3d <linestyle> explicit 
is neccessary to avoid some strange visual behavior (the patch is opaque but 
the axes are visible even if they should be hidden by the patch) the hidden3d 
(not the pm3d hidden3d) setting seems to be responsible for that.
Hope I will find time over the weekend to dive deeper into it and understand 
the details.

- mh

isofunctions.diff.bz2
Description: application/bzip

isofunctions_makefile_in.diff.bz2
Description: application/bzip