Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/nurbs-1.3.6/bspeval.m b/octave_packages/nurbs-1.3.6/bspeval.m
new file mode 100644 (file)
index 0000000..5a3ed9e
--- /dev/null
+++ b/octave_packages/nurbs-1.3.6/bspeval.m
@@ -0,0 +1,72 @@
+function p = bspeval(d,c,k,u)
+
+% BSPEVAL:  Evaluate B-Spline at parametric points.
+% 
+% Calling Sequence:
+% 
+%   p = bspeval(d,c,k,u)
+% 
+%    INPUT:
+% 
+%       d - Degree of the B-Spline.
+%       c - Control Points, matrix of size (dim,nc).
+%       k - Knot sequence, row vector of size nk.
+%       u - Parametric evaluation points, row vector of size nu.
+% 
+%    OUTPUT:
+%
+%       p - Evaluated points, matrix of size (dim,nu)
+% 
+%    Copyright (C) 2000 Mark Spink, 2007 Daniel Claxton, 2010 C. de Falco
+%
+%    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/>.
+
+nu = numel(u);
+[mc,nc] = size(c);
+                                                %   int bspeval(int d, double *c, int mc, int nc, double *k, int nk, double *u,int nu, double *p){
+                                                %   int ierr = 0;
+                                                %   int i, s, tmp1, row, col;
+                                                %   double tmp2;
+                                                %
+                                                %   // Construct the control points
+                                                %   double **ctrl = vec2mat(c,mc,nc);
+                                                %
+                                                %   // Contruct the evaluated points
+p = zeros(mc,nu);                               %   double **pnt = vec2mat(p,mc,nu);
+                                                %
+                                                %   // space for the basis functions
+%N = zeros(d+1,1);                               %   double *N = (double*) mxMalloc((d+1)*sizeof(double));
+                                                %
+                                                %   // for each parametric point i
+%for col=1:nu                                    %   for (col = 0; col < nu; col++) {
+                                                %     // find the span of u[col]
+    s = findspan(nc-1, d, u(:), k);           %     s = findspan(nc-1, d, u[col], k);
+    N = basisfun(s,u(:),d,k);                 %     basisfun(s, u[col], d, k, N);
+                                                %
+    tmp1 = s - d + 1;                           %     tmp1 = s - d;
+    %for row=1:mc                                %     for (row = 0; row < mc; row++)  {
+        p = zeros (mc, nu);                               %       tmp2 = 0.0;
+        for i=0:d                               %       for (i = 0; i <= d; i++)
+           p = p + repmat (N(:,i+1)', mc, 1).*c(:,tmp1+i);  %  tmp2 += N[i] * ctrl[tmp1+i][row];
+        end                                     %
+        %p(row,:) = tmp2;                      %       pnt[col][row] = tmp2;
+    %end                                         %     }
+%end                                             %   }
+                                                %
+                                                %   mxFree(N);
+                                                %   freevec2mat(pnt);
+                                                %   freevec2mat(ctrl);
+                                                %
+                                                %   return ierr;
+end                                             %   }