Mercurial > hg > octave-nkf
changeset 14514:34a9fdaa6ea3
New Function, tetramesh.m
* tetramesh.m: New File.
* scripts/plot/module.mk: Add new file.
author | Martin Helm <martin@mhelm.de> |
---|---|
date | Mon, 02 Apr 2012 19:34:31 -0400 |
parents | 3313635c622d |
children | 273fdfcdbb85 |
files | scripts/plot/module.mk scripts/plot/tetramesh.m |
diffstat | 2 files changed, 162 insertions(+), 0 deletions(-) [+] |
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--- a/scripts/plot/module.mk +++ b/scripts/plot/module.mk @@ -175,6 +175,7 @@ plot/surfc.m \ plot/surfl.m \ plot/surfnorm.m \ + plot/tetramesh.m \ plot/text.m \ plot/title.m \ plot/trimesh.m \
new file mode 100644 --- /dev/null +++ b/scripts/plot/tetramesh.m @@ -0,0 +1,161 @@ +## Copyright (C) 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} tetramesh (@var{T}, @var{X}) +## @deftypefnx {Function File} tetramesh (@var{T}, @var{X}, @var{C}) +## @deftypefnx {Function File} {[@var{h}] =} tetramesh (...) +## @deftypefnx {Function File} {[@var{h}] =} tetramesh (..., @var{PROP}, @var{VAL}) +## +## The function displays the tetrahedrons defined in the m by 4 matrix @var{T} +## as 3D patches. @var{T} is usually the output of a Delaunay triangulation of a +## 3D set of points. +## Every row of @var{T} contains four indices into the n by 3 matrix @var{X} +## of the vertices of a tetrahedron. +## Every row in @var{X} represents one point in 3D space. +## +## If the vector @var{C} is supplied it must contain indices into the current +## colormap. Called without @var{C} it is set to 1:m, where m is the number of +## tetrahedrons, the indices are scaled to map to the full range of the colormap. +## If more tetrahedrons than entries in the colormap are given the entries of +## @var{C} are cyclic repeated. +## +## When called with one output argument @var{H} it returns a vector of patch +## handles,each representing one tetrahedron in the order given by @var{T}. +## One use case for @var{H} is to turn the respective patch 'Visible' property +## 'on' or 'off'. +## +## Calling tetramesh(...,'param','value','param','value'...) passes all +## option/value pairs directly as additional arguments to the patch function for +## every tetrahedron. +## +## The command +## +##@example +## @group +## demo tetramesh +## @end group +## @end example +## +## @noindent +## will show some examples how to use it. +#### @seealso{patch} +## @end deftypefn + +## Author: Martin Helm <martin@mhelm.de> + +function [h] = tetramesh (varargin) + + [reg, prop] = parseparams (varargin); + + if (length (reg) < 2 || length (reg) > 3) + print_usage () + endif + + T = reg{1}; + X = reg{2}; + + if (! ismatrix (T) || size (T, 2) != 4) + error ("tetramesh: T must be a n by 4 matrix") + endif + if (! ismatrix (X) || size (X, 2) != 3) + error ("tetramesh: X must be a n by 3 matrix") + endif + + size_T = size (T, 1); + colmap = colormap (); + + # do we need to enable gnuplot workaround? + shrink = strcmp (graphics_toolkit (), "gnuplot"); + + if (length (reg) < 3) + size_colmap = size (colmap, 1); + C = mod ((1:size_T)' - 1, size_colmap) + 1; + if (size_T < size_colmap && size_T > 1) + # expand to the available range of colors + C = floor ((C - 1) * (size_colmap - 1) / (size_T - 1)) + 1; + endif + else + C = reg{3}; + if (! isvector (C) || size_T != length (C)) + error ("tetramesh: C must be a vector of the same length as T") + endif + endif + + h = zeros (1, size_T); + if (shrink) + # tiny reduction of the tetrahedron size to help gnuplot by + # avoiding identical faces with different colors + for ii = 1:size_T + [th, p] = __shrink__ ([1 2 3 4], X(T(ii, :), :), 1 - 1e-7); + h(ii) = patch ("Faces", th, "Vertices", p, "FaceColor", ... + colmap(C(ii), :), prop{:}); + endfor + else + for ii = 1:size_T + th = [1 2 3; 2 3 4; 3 4 1; 4 1 2]; + h(ii) = patch ("Faces", th, "Vertices", X(T(ii, :), :), "FaceColor", ... + colmap(C(ii), :), prop{:}); + endfor + endif + + if (nargout == 0) #return nothing + clear h; + endif +endfunction + +## shrink the tetrahedron relative to its center of gravity +function [tri, p] = __shrink__ (T, X, sf) + midpoint = repmat (sum (X(T, :), 1) / 4, 12, 1); + p = [X([1 2 3], :); X([2 3 4], :); X([3 4 1], :); X([4 1 2], :)]; + p = sf * (p - midpoint) + midpoint; + tri = reshape (1:12, 3, 4)'; +endfunction + +%!demo +%! d = [-1 1]; +%! [x,y,z] = meshgrid (d, d, d); +%! x = [x(:); 0]; +%! y = [y(:); 0]; +%! z = [z(:); 0]; +%! tetra = delaunay3 (x, y, z); +%! X = [x(:) y(:) z(:)]; +%! clf () +%! colormap (jet (64)) +%! h = tetramesh (tetra, X); +%! for ii=1:2:length(h); +%! set(h(ii), "Visible", "off"); +%! endfor +%! axis equal +%! view (30, 20) +%! title ("Using jet (64), every other tetrahedron invisible") + +%!demo +%! d = [-1 1]; +%! [x,y,z] = meshgrid (d, d, d); +%! x = [x(:); 0]; +%! y = [y(:); 0]; +%! z = [z(:); 0]; +%! tetra = delaunay3 (x, y, z); +%! X = [x(:) y(:) z(:)]; +%! clf () +%! colormap (gray (256)); +%! tetramesh (tetra, X, 21:20:241, "EdgeColor", "w") +%! axis equal +%! view (30, 20) +%! title ("Using gray (256) and white edges")