Mercurial > octave
view scripts/plot/draw/isonormals.m @ 22323:bac0d6f07a3e
maint: Update copyright notices for 2016.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Wed, 17 Aug 2016 01:05:19 -0400 |
parents | 533c3c4059a3 |
children | 81387a85a403 |
line wrap: on
line source
## Copyright (C) 2009-2016 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 {} {[@var{vn}] =} isonormals (@var{val}, @var{vert}) ## @deftypefnx {} {[@var{vn}] =} isonormals (@var{val}, @var{hp}) ## @deftypefnx {} {[@var{vn}] =} isonormals (@var{x}, @var{y}, @var{z}, @var{val}, @var{vert}) ## @deftypefnx {} {[@var{vn}] =} isonormals (@var{x}, @var{y}, @var{z}, @var{val}, @var{hp}) ## @deftypefnx {} {[@var{vn}] =} isonormals (@dots{}, "negate") ## @deftypefnx {} {} isonormals (@var{val}, @var{hp}) ## @deftypefnx {} {} isonormals (@var{x}, @var{y}, @var{z}, @var{val}, @var{hp}) ## @deftypefnx {} {} isonormals (@dots{}, "negate") ## ## Calculate normals to an isosurface. ## ## The vertex normals @var{vn} are calculated from the gradient of the ## 3-dimensional array @var{val} (size: lxmxn) with the data for an ## isosurface geometry. The normals point towards lower values in @var{val}. ## ## If called with one output argument @var{vn} and the second input argument ## @var{vert} holds the vertices of an isosurface, the normals @var{vn} are ## calculated at the vertices @var{vert} on a grid given by ## @code{[x, y, z] = meshgrid (1:l, 1:m, 1:n)}. The output argument ## @var{vn} has the same size as @var{vert} and can be used to set the ## @qcode{"VertexNormals"} property of the corresponding patch. ## ## If called with further input arguments @var{x}, @var{y}, and @var{z} ## which are 3-dimensional arrays with the same size as @var{val}, ## the volume data is taken at these points. Instead of the vertex data ## @var{vert}, a patch handle @var{hp} can be passed to this function. ## ## If the last input argument is the string @qcode{"negate"}, compute the ## reverse vector normals of an isosurface geometry (i.e., pointed towards ## higher values in @var{val}). ## ## If no output argument is given, the property @qcode{"VertexNormals"} of ## the patch associated with the patch handle @var{hp} is changed directly. ## ## @seealso{isosurface, isocolors, smooth3} ## @end deftypefn ## Author: Martin Helm <martin@mhelm.de> function varargout = isonormals (varargin) na = nargin; negate = false; if (ischar (varargin{na})) if (strcmpi (varargin{na}, "negate")) negate = true; else error ("isonormals: Unknown option '%s'", varargin{nargin}); endif na = nargin-1; endif switch (na) case 2 val = varargin{1}; vp = varargin{2}; x = 1:size (val, 2); y = 1:size (val, 1); z = 1:size (val, 3); case 5 x = varargin{1}; y = varargin{2}; z = varargin{3}; val = varargin{4}; vp = varargin{5}; otherwise print_usage (); endswitch if (isnumeric (vp) && columns (vp) == 3) pa = []; v = vp; elseif (ishghandle (vp, "patch")) pa = vp; v = get (pa, "Vertices"); else error ("isonormals: input must be a list of vertices or a patch handle"); endif if (negate) normals = __interp_cube__ (x, y, z, val, v, "normals"); else normals = -__interp_cube__ (x, y, z, val, v, "normals"); endif switch (nargout) case 0 if (! isempty (pa)) set (pa, "VertexNormals", normals); endif case 1 varargout = {normals}; otherwise print_usage (); endswitch endfunction %!demo %! function isofinish (hp) %! axis equal; %! set (hp, "VertexNormals", -get (hp, "VertexNormals")); # Revert normals %! shading interp; %! set (hp, "FaceLighting", "gouraud"); %! set (hp, "BackFaceLighting", "unlit"); %! light (); %! 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); %! val = (x-.5).^2 + (y-.5).^2 + (z-.5).^2; %! clf; %! %! subplot (2,2,1); %! view (-38, 20); %! [fac, vert, cdat] = isosurface (x, y, z, val, iso, y); %! hp = patch ("Faces", fac, "Vertices", vert, "FaceVertexCData", cdat); %! title ("without isonormals"); %! isofinish (hp); %! %! subplot (2,2,2); %! view (-38, 20); %! hp = patch ("Faces", fac, "Vertices", vert, "FaceVertexCData", cdat); %! title ("patch modified by isonormals"); %! isonormals (x, y, z, val, hp); # Directly modify patch %! isofinish (hp); %! %! subplot (2,2,3); %! view (-38, 20); %! hp = patch ("Faces", fac, "Vertices", vert, "FaceVertexCData", cdat); %! vn = isonormals (x, y, z, val, vert); # Compute normals of isosurface %! set (hp, "VertexNormals", vn); # Manually set vertex normals %! title ('set "VertexNormals" from isonormals'); %! isofinish (hp); %! %! subplot (2,2,4); %! view (-38, 20); %! hp = patch ("Faces", fac, "Vertices", vert, "FaceVertexCData", cdat); %! isonormals (x, y, z, val, hp, "negate"); # Use reverse directly %! title ('patch modified by isonormals (..., "negate")'); %! isofinish (hp); %!shared x,y,z,val,vert %! [x, y, z] = meshgrid (0:.5:2, 0:.5:2, 0:.5:2); %! val = abs ((x-.5).^2 + (y-.3).^2 + (z-.4).^2); %! [fac, vert, cdat] = isosurface (x, y, z, val, .4, y); %!test %! vn = isonormals (x, y, z, val, vert); %! assert (size (vert), size (vn)); %!test %! np = isonormals (x, y, z, val, vert); %! nn = isonormals (x, y, z, val, vert, "negate"); %! assert (np, -nn); %!test %! [x,y,z] = meshgrid (-2:1:2, -2:1:2, -2:1:2); %! val = x.^2 + y.^2 + z.^2; %! [f,vert] = isosurface (x, y, z, val, 1); %! vn = isonormals (x, y, z, val, vert); %! dirn = vert ./ vn; %! assert (all (dirn(isfinite (dirn)) <= 0)); %!error <Unknown option 'foo'> n = isonormals (x, y, z, val, vert, "foo") %!error <input must be a list of vertices or a patch handle> %! n = isonormals (x, y, z, val, x);