Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nurbs-1.3.6 / nrbctrlplot.m

diff --git a/octave_packages/nurbs-1.3.6/nrbctrlplot.m b/octave_packages/nurbs-1.3.6/nrbctrlplot.m
new file mode 100644 (file)
index 0000000..5b976ba
--- /dev/null
+++ b/octave_packages/nurbs-1.3.6/nrbctrlplot.m
@@ -0,0 +1,104 @@
+function nrbctrlplot (nurbs)
+
+% NRBCTRLPLOT: Plot a NURBS entity along with its control points.
+% 
+% Calling Sequence:
+% 
+%   nrbctrlplot (nurbs)
+% 
+% INPUT:
+% 
+%   nurbs: NURBS curve or surface, see nrbmak.
+% 
+% Example:
+%
+%   Plot the test curve and test surface with their control polygon and
+%    control net, respectively
+%
+%   nrbctrlplot(nrbtestcrv)
+%   nrbctrlplot(nrbtestsrf)
+%
+% See also:
+% 
+%   nrbkntplot
+%
+%    Copyright (C) 2011 Rafael Vazquez
+%
+%    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 2 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/>.
+
+if (nargin < 1)
+  error ('nrbctrlplot: Need a NURBS to plot!');
+end
+
+% Default values
+light='on';
+cmap='summer';
+
+colormap (cmap);
+
+hold_flag = ishold;
+
+if (iscell (nurbs.knots))
+  if (size (nurbs.knots,2) == 3)
+    error ('nrbctrlplot: not implemented for NURBS volumes');
+  elseif (size (nurbs.knots,2) == 2) % plot a NURBS surface
+
+    nsub = 100;
+    nrbplot (nurbs, [nsub nsub], 'light', light, 'colormap', cmap);
+    hold on
+
+% And plot the control net
+    for ii = 1:size (nurbs.coefs, 2)
+      coefs = reshape (nurbs.coefs(1:3,ii,:), 3, []);
+      weights = reshape (nurbs.coefs(4,ii,:), 1, []);
+      plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'k--')
+      plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'r.','MarkerSize',20)
+    end
+    for jj = 1:size (nurbs.coefs, 3)
+      coefs = reshape (nurbs.coefs(1:3,:,jj), 3, []);
+      weights = reshape (nurbs.coefs(4,:,jj), 1, []);
+      plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'k--')
+      plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'r.','MarkerSize',20)
+    end
+  end
+else % plot a NURBS curve
+  nsub = 1000;
+  nrbplot (nurbs, nsub);
+  hold on
+
+% And plot the control polygon
+  coefs = nurbs.coefs(1:3,:);
+  weights = nurbs.coefs(4,:);
+  plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'k--')
+  plot3 (coefs(1,:)./weights, coefs(2,:)./weights, coefs(3,:)./weights,'r.','MarkerSize',20)
+end
+
+if (~hold_flag)
+  hold off
+end
+
+end
+
+%!demo
+%! crv = nrbtestcrv;
+%! nrbctrlplot(crv)
+%! title('Test curve')
+%! hold off
+
+%!demo
+%! srf = nrbtestsrf;
+%! nrbctrlplot(srf)
+%! title('Test surface')
+%! hold off
+