--- /dev/null
+## Copyright (C) 2009-2012 Martin Helm
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING. If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- 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 three-dimensional 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 three--dimensional 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:
+## @c Set example in small font to prevent overfull line
+##
+## @smallexample
+## function [] = isofinish (p)
+## set (gca, "PlotBoxAspectRatioMode", "manual", ...
+## "PlotBoxAspectRatio", [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 smallexample
+##
+## @seealso{isosurface, isocolors}
+## @end deftypefn
+
+## Author: Martin Helm <martin@mhelm.de>
+
+function varargout = isonormals(varargin)
+ na = nargin;
+ negate = false;
+ if (ischar (varargin{nargin}))
+ na = nargin-1;
+ if (strcmp (lower (varargin{nargin}), "negate"))
+ negate = true;
+ else
+ error ("isonormals: Unknown option '%s'", varargin{nargin});
+ endif
+ endif
+ switch (na)
+ case 2
+ c = varargin{1};
+ vp = varargin{2};
+ x = 1:size (c, 2);
+ y = 1:size (c, 1);
+ z = 1:size (c, 3);
+ case 5
+ x = varargin{1};
+ y = varargin{2};
+ z = varargin{3};
+ c = varargin{4};
+ vp = varargin{5};
+ otherwise
+ print_usage ();
+ endswitch
+ if (ismatrix (vp) && size (vp,2) == 3)
+ pa = [];
+ v = vp;
+ elseif (ishandle (vp))
+ pa = vp;
+ v = get (pa, "Vertices");
+ else
+ error ("isonormals: Last argument is not a vertex list or a patch handle");
+ endif
+ if (negate)
+ normals = -__interp_cube__ (x, y, z, c, v, "normals");
+ else
+ normals = __interp_cube__ (x, y, z, c, v, "normals");
+ endif
+ switch (nargout)
+ case 0
+ if (!isempty (pa))
+ set (pa, "VertexNormals", normals);
+ endif
+ case 1
+ varargout = {normals};
+ otherwise
+ print_usage ();
+ endswitch
+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));
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff