Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / vrml-1.0.13 / vrml_flatten.m

diff --git a/octave_packages/vrml-1.0.13/vrml_flatten.m b/octave_packages/vrml-1.0.13/vrml_flatten.m
new file mode 100644 (file)
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+++ b/octave_packages/vrml-1.0.13/vrml_flatten.m
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+## Copyright (C) 2002 Etienne Grossmann <etienne@egdn.net>
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## s = vrml_flatten (x [, d, w, col]) - A planar surface containing x
+##
+## If the points  x  are not coplanar (or not in the affine plane {y|d'*y==w}),
+## the surface will not contain the points, but rather their projections on
+## the plane {y|d'*y==w}.
+## 
+## x   : 3 x P  : 3D points
+## d   : 3      : normal to plane    | Default : given by best_dir()
+## w   : 1      : intercept of plane |
+## col : 3      : RGB color            Default : [0.3,0.4,0.9]
+##
+## s   : string : vrml code representing the planar surface
+
+function s = vrml_flatten (x, d, w, col)
+
+
+if     nargin <= 3 || isnan (col),  col = [0.3,0.4,0.9];  end
+if     nargin <= 1 || isnan (d),    [d,w] = best_dir (x); 
+elseif nargin <= 2 || isnan (w),    w = mean (d'*x); end
+if   ! nargin,       error ("vrml_flatten : no arguments given"); end 
+
+y = bound_convex (d,w,x);
+Q = columns (y);
+faces = [ones(1,Q-2); 2:Q-1; 3:Q];
+
+
+s = vrml_faces (y, faces, "col",col);
+endfunction
+