update packages

[CreaPhase.git] / octave_packages / m / plot / ellipsoid.m

diff --git a/octave_packages/m/plot/ellipsoid.m b/octave_packages/m/plot/ellipsoid.m
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+## Copyright (C) 2007-2012 Sylvain Pelissier
+##
+## 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{x}, @var{y}, @var{z}] =} ellipsoid (@var{xc}, @var{yc}, @var{zc}, @var{xr}, @var{yr}, @var{zr}, @var{n})
+## @deftypefnx {Function File} {} ellipsoid (@var{h}, @dots{})
+## Generate three matrices in @code{meshgrid} format that define an
+## ellipsoid.  Called with no return arguments, @code{ellipsoid} calls
+## directly @code{surf (@var{x}, @var{y}, @var{z})}.  If an axes handle
+## is passed as the first argument, the surface is plotted to this
+## set of axes.
+## @seealso{sphere}
+## @end deftypefn
+
+## Author: Sylvain Pelissier <sylvain.pelissier@gmail.com>
+
+function [xx, yy, zz] = ellipsoid (varargin)
+
+  [h, varargin, nargin] = __plt_get_axis_arg__ ((nargout > 0), "ellipsoid",
+                                                varargin{:});
+
+  if (nargin != 6 && nargin != 7)
+    print_usage ();
+  endif
+
+  xc = varargin{1};
+  yc = varargin{2};
+  zc = varargin{3};
+  xr = varargin{4};
+  yr = varargin{5};
+  zr = varargin{6};
+
+  if (nargin == 6)
+    n = 20;
+  else
+    n = varargin{7};
+  endif
+
+  theta = linspace (0, 2 * pi, n + 1);
+  phi = linspace (-pi / 2, pi / 2, n + 1);
+  [theta, phi] = meshgrid (theta, phi);
+
+  x = xr .* cos (phi) .* cos (theta) + xc;
+  y = yr .* cos (phi) .* sin (theta) + yc;
+  z = zr .* sin (phi) + zc;
+
+  if (nargout > 0)
+    xx = x;
+    yy = y;
+    zz = z;
+  else
+    surf (h, x, y, z);
+  endif
+
+endfunction
+
+%!demo
+%! clf
+%! ellipsoid (0, 0, 1, 2, 3, 4, 20);