Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nurbs-1.3.6 / private / nrb_srf_numbasisfun__.m

diff --git a/octave_packages/nurbs-1.3.6/private/nrb_srf_numbasisfun__.m b/octave_packages/nurbs-1.3.6/private/nrb_srf_numbasisfun__.m
new file mode 100644 (file)
index 0000000..3dd0e8b
--- /dev/null
+++ b/octave_packages/nurbs-1.3.6/private/nrb_srf_numbasisfun__.m
@@ -0,0 +1,34 @@
+function idx = nrb_srf_numbasisfun__ (points, nrb)
+
+%  __NRB_SRF_NUMBASISFUN__: Undocumented internal function
+%
+%   Copyright (C) 2009 Carlo de Falco
+%   This software comes with ABSOLUTELY NO WARRANTY; see the file
+%   COPYING for details.  This is free software, and you are welcome
+%   to distribute it under the conditions laid out in COPYING.
+  
+  m   = nrb.number(1)-1;
+  n   = nrb.number(2)-1;
+  
+  npt = size(points,2);
+  u   = points(1,:);
+  v   = points(2,:);
+
+  U   = nrb.knots{1};
+  V   = nrb.knots{2};
+
+  p   = nrb.order(1)-1;
+  q   = nrb.order(2)-1;
+
+  spu = findspan (m, p, u, U); 
+  Ik  = numbasisfun (spu, u, p, U);
+
+  spv = findspan (n, q, v, V);
+  Jk  = numbasisfun (spv, v, q, V);
+  
+  for k=1:npt
+    [Jkb, Ika] = meshgrid(Jk(k, :), Ik(k, :)); 
+    idx(k, :)  = sub2ind([m+1, n+1], Ika(:)+1, Jkb(:)+1);
+  end
+
+end