David Bateman schrieb:
> Martin Helm wrote:
>> First of all,
>>
>> thank you for your effort David. I can confirm the errors reported by
>> Thomas. To be precise they happen with the first two examples in the
>> "subplot" example group which use the syntax
>> patch ("Faces", f, "Vertices", v, "EdgeColor", whatever)
>>
>> The other two examples which use "FaceVertexCData" and facecoloring
>> work well.
>>
>> If I simply add the "FaceColor" attribute with some value to the
>> failing patch command, the problem disappears, so the bug seems to be
>> trivial (a misssing default value for "FaceColor")
>>
>> e.g.
>>
>> patch ("Faces", f, "Vertices", v, "FaceColor", "blue","EdgeColor",
>> "none")
>>
>> works well. I'll look through the code.
>>
>>  mh
>>
> The old 3.0.x behavior was that the default facecolor was [0,1,0]. I
> presume that is the compatible behavior and so reestablished that as
> the default with the attached patch. The demo in the help string then
> works correctly for the gnuplot CVS. But there appear to be some issue
> with colormap with gnuplot 4.2.4 and the x11 terminal in a multiplot
> environment.. I suppose I should try 4.2.5 and see if that works
>
> D.
Hi David, Martin,
thanks again for this work. I'd say that this is really a very cool new feature
that then comes with 3.2...
Some time ago I also was working on the help text of isonormals.m and
__marching_cubes__.m (Martin already knows because I wrote him an email some
time ago offside the lists to preserve doublework ;) David, can you please
apply the attached changeset?
Thanks and best regards,
Thomas
# HG changeset patch
# User Thomas Treichl <
[hidden email]>
# Date 1239739325 7200
# Node ID 3b810beddfa64d947c1fe399b17f325d70e0eac1
# Parent 308311b642b2be2c4e171e15b9e8f35ea4615975
Added help texts and tests.
diff git a/scripts/ChangeLog b/scripts/ChangeLog
 a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ 1,4 +1,9 @@
20090411 David Bateman <
[hidden email]>
+20090414 Thomas Treichl <
[hidden email]>
+
+ * plot/__marching_cube__.m: Add help text.
+ * plot/isonormals.m: Add help text and tests.
+
+20090414 David Bateman <
[hidden email]>
* plot/__patch__.m: Set default facecolor to [0,1,0].
diff git a/scripts/plot/__marching_cube__.m b/scripts/plot/__marching_cube__.m
 a/scripts/plot/__marching_cube__.m
+++ b/scripts/plot/__marching_cube__.m
@@ 12,52 +12,63 @@
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, see
http://www.gnu.org/licenses/gpl.html.
+
+## * texinfo *
+## @deftypefn {Function File} {[@var{t}, @var{p}] =} __marching_cube__ (@var{x}, @var{y}, @var{z}, @var{val}, @var{iso})
+## @deftypefn {Function File} {[@var{t}, @var{p}, @var{c}] =} __marching_cube__ (@var{x}, @var{y}, @var{z}, @var{val}, @var{iso}, @var{col})
##
+## Return the triangulation information @var{t} at points @var{p} for
+## the isosurface values resp. the volume data @var{val} and the iso
+## level @var{iso}. It is considered that the volume data @var{val} is
+## given at the points @var{x}, @var{y} and @var{z} which are of type
+## threedimensional numeric arrays. The orientation of the triangles
+## is choosen such that the normals point from the higher values to the
+## lower values.
+##
+## Optionally the color data @var{col} can be passed to this function
+## whereas computed vertices color data @var{c} is returned as third
+## argument.
+##
+## The marching cube algorithm is well known and described eg. at
+## Wikipedia. The triangulation lookup table and the edge table used
+## here are based on Cory Gene Bloyd's implementation and can be found
+## beyond other surface and geometry stuff at Paul Bourke's website
+## @uref{
http://local.wasp.uwa.edu.au/~pbourke/geometry/polygonise}.
+##
+## For example,
+## @example
+## N = 20;
+## lin = linspace(0, 2, N);
+## [x, y, z] = meshgrid (lin, lin, lin);
+##
+## c = (x.5).^2 + (y.5).^2 + (z.5).^2;
+## [t, p] = __marching_cube__ (x, y, z, c, .5);
+##
+## figure ();
+## trimesh (t, p(:,1), p(:,2), p(:,3));
+## @end example
+##
+## Instead of the @command{trimesh} function the @command{patch}
+## function can be used to visualize the geometry. For example,
+##
+## @example
+## figure (); view (38, 20);
+## pa = patch ("Faces", t, "Vertices", p, "FaceVertexCData", p, \
+## "FaceColor", "interp", "EdgeColor", "none");
+##
+## ## Revert normals
+## set (pa, "VertexNormals", get(pa, "VertexNormals"));
+##
+## ## Set lightning (available with the JHandles package)
+## # set (pa, "FaceLighting", "gouraud");
+## # light( "Position", [1 1 5]);
+## @end example
+##
+## @end deftypefn
+
## Author: Martin Helm <
[hidden email]>
## * texinfo *
## @deftypefn {Function File} {[@var{t}, @var{p}, @var{col}] =} __marching_cube__ (@var{x}, @var{y}, @var{z}, @var{c}, @var{iso}, @var{color})
## Undocumented internal function.
## @end deftypefn

## usage: [T, P] = marching_cube( XX, YY, ZZ, C, ISO)
## usage: [T, P, COL] = marching_cube( XX, YY, ZZ, C, ISO, COLOR)
##
## Calculates the triangulation T with points P for the isosurface
## with level ISO. XX, YY, ZZ are meshgrid like values for the
## cube and C holds the scalar values of the field,
## COLOR holds additinal scalar values for coloring the surface.
## The orientation of the triangles is choosen such that the
## normals point from the lower values to the higher values.
##
## edgeTable and triTable are taken from Paul Bourke
## (
http://local.wasp.uwa.edu.au/~pbourke/geometry/polygonise/)
## Based on tables by Cory Gene Bloyd
##
## Example:
##
## x = linspace(0, 2, 20);
## y = linspace(0, 2, 20);
## z = linspace(0, 2, 20);
##
## [ xx, yy, zz ] = meshgrid(x, y, z);
##
## c = (xx.5).^2 + (yy.5).^2 + (zz.5).^2;
## [T, p] = marching_cube(xx, yy, zz, c, 0.5);
## trimesh(T, p(:, 1), p(:, 2), p(:, 3));
##
## with jhandles you can also use the patch function to visualize
##
## clf
## pa = patch('Faces',T,'Vertices',p,'FaceVertexCData',p, ...
## 'FaceColor','interp', 'EdgeColor', 'none');
## set(pa, "VertexNormals", get(pa, "VertexNormals")) # revert normals
## view(30, 30)
## set(pa, "FaceLighting", "gouraud")
## light( "Position", [1 1 5])
##

function [T, p, col] = __marching_cube__( xx, yy, zz, c, iso, colors)
+function [T, p, col] = __marching_cube__ (xx, yy, zz, c, iso, colors)
persistent edge_table=[];
persistent tri_table=[];
@@ 502,4 +513,4 @@
0, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1;
0, 3, 8, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1;
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ] + 1;
endfunction
\ No newline at end of file
+endfunction
diff git a/scripts/plot/isonormals.m b/scripts/plot/isonormals.m
 a/scripts/plot/isonormals.m
+++ b/scripts/plot/isonormals.m
@@ 12,17 +12,83 @@
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, see
http://www.gnu.org/licenses/gpl.html.
+
+## * texinfo *
+## @deftypefn {Function File} {[@var{n}] =} isonormals (@var{val}, @var{v})
+## @deftypefnx {Function File} {[@var{n}] =} isonormals (@var{val}, @var{p})
+## @deftypefnx {Function File} {[@var{n}] =} isonormals (@var{x}, @var{y}, @var{z}, @var{val}, @var{v})
+## @deftypefnx {Function File} {[@var{n}] =} isonormals (@var{x}, @var{y}, @var{z}, @var{val}, @var{p})
+## @deftypefnx {Function File} {[@var{n}] =} isonormals (@dots{}, "negate")
+## @deftypefnx {Function File} isonormals (@dots{}, @var{p})
##
+## If called with one output argument and the first input argument
+## @var{val} is a threedimensional array that contains the data for an
+## isosurface geometry and the second input argument @var{v} keeps the
+## vertices of an isosurface then return the normals @var{n} in form of
+## a matrix with the same size than @var{v} at computed points
+## @command{[x, y, z] = meshgrid (1:l, 1:m, 1:n)}. The output argument
+## @var{n} can be taken to manually set @var{VertexNormals} of a patch.
+##
+## If called with further input arguments @var{x}, @var{y} and @var{z}
+## which are threedimensional arrays with the same size than @var{val}
+## then the volume data is taken at those given points. Instead of the
+## vertices data @var{v} a patch handle @var{p} can be passed to this
+## function.
+##
+## If given the string input argument "negate" as last input argument
+## then compute the reverse vector normals of an isosurface geometry.
+##
+## If no output argument is given then directly redraw the patch that is
+## given by the patch handle @var{p}.
+##
+## For example,
+## @example
+## function [] = isofinish (p)
+## set (gca, "DataAspectRatioMode","manual","DataAspectRatio",[1 1 1]);
+## set (p, "VertexNormals", get(p,"VertexNormals")); ## Revert normals
+## set (p, "FaceColor", "interp");
+## ## set (p, "FaceLighting", "phong");
+## ## light ("Position", [1 1 5]); ## Available with JHandles
+## endfunction
+##
+## N = 15; ## Increase number of vertices in each direction
+## iso = .4; ## Change isovalue to .1 to display a sphere
+## lin = linspace (0, 2, N);
+## [x, y, z] = meshgrid (lin, lin, lin);
+## c = abs ((x.5).^2 + (y.5).^2 + (z.5).^2);
+## figure (); ## Open another figure window
+##
+## subplot (2, 2, 1); view (38, 20);
+## [f, v, cdat] = isosurface (x, y, z, c, iso, y);
+## p = patch ("Faces", f, "Vertices", v, "FaceVertexCData", cdat, \
+## "FaceColor", "interp", "EdgeColor", "none");
+## isofinish (p); ## Call user function isofinish
+##
+## subplot (2, 2, 2); view (38, 20);
+## p = patch ("Faces", f, "Vertices", v, "FaceVertexCData", cdat, \
+## "FaceColor", "interp", "EdgeColor", "none");
+## isonormals (x, y, z, c, p); ## Directly modify patch
+## isofinish (p);
+##
+## subplot (2, 2, 3); view (38, 20);
+## p = patch ("Faces", f, "Vertices", v, "FaceVertexCData", cdat, \
+## "FaceColor", "interp", "EdgeColor", "none");
+## n = isonormals (x, y, z, c, v); ## Compute normals of isosurface
+## set (p, "VertexNormals", n); ## Manually set vertex normals
+## isofinish (p);
+##
+## subplot (2, 2, 4); view (38, 20);
+## p = patch ("Faces", f, "Vertices", v, "FaceVertexCData", cdat, \
+## "FaceColor", "interp", "EdgeColor", "none");
+## isonormals (x, y, z, c, v, "negate"); ## Use reverse directly
+## isofinish (p);
+## @end example
+##
+## @seealso {isosurface, isocolors, isocaps, marching_cube}
+##
+## @end deftypefn
+
## Author: Martin Helm <
[hidden email]>

## usage: NORMALS = isonormals(X,Y,Z,V,VERT)
## usage: NORMALS = isonormals(V,VERT)
## usage: NORMALS = isonormals(V,P)
## usage: NORMALS = isonormals(X,Y,Z,V,P)
## usage: NORMALS = isonormals(...,'negate')
## usage: isonormals(V,P)
## usage: isonormals(X,Y,Z,V,P)
##
function varargout = isonormals(varargin)
na = nargin;
@@ 75,4 +141,18 @@
otherwise
print_usage ();
endswitch
endfunction
\ No newline at end of file
+endfunction
+
+%!test
+%! [x, y, z] = meshgrid (0:.5:2, 0:.5:2, 0:.5:2);
+%! c = abs ((x.5).^2 + (y.5).^2 + (z.5).^2);
+%! [f, v, cdat] = isosurface (x, y, z, c, .4, y);
+%! n = isonormals (x, y, z, c, v);
+%! assert (size (v), size (n));
+%!test
+%! [x, y, z] = meshgrid (0:.5:2, 0:.5:2, 0:.5:2);
+%! c = abs ((x.5).^2 + (y.5).^2 + (z.5).^2);
+%! [f, v, cdat] = isosurface (x, y, z, c, .4, y);
+%! np = isonormals (x, y, z, c, v);
+%! nn = isonormals (x, y, z, c, v, "negate");
+%! assert (all (np == nn));