Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/nurbs-1.3.6/vecrot.m b/octave_packages/nurbs-1.3.6/vecrot.m
new file mode 100644 (file)
index 0000000..d8ed20d
--- /dev/null
+++ b/octave_packages/nurbs-1.3.6/vecrot.m
@@ -0,0 +1,53 @@
+function rx = vecrot(angle, vector)
+% 
+% VECROT: Transformation matrix for a rotation around the axis given by a vector. 
+% 
+% Calling Sequence:
+% 
+%   rx = vecrot (angle, vector);
+% 
+% INPUT:
+% 
+%   angle              : rotation angle defined in radians
+%   vector             : vector defining the rotation axis
+%
+% OUTPUT:
+% 
+%   rx         : (4x4) Transformation matrix.
+% 
+% 
+% Description:
+% 
+%   Return the (4x4) Transformation matrix for a rotation about the x axis
+%   by the defined angle.
+% 
+% See also:
+% 
+%    nrbtform
+%
+%    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/>.
+
+% Normalize the vector
+vec = vector / norm (vector);
+
+sn = sin (angle);
+cn = cos (angle);
+rx = [cn+vec(1)^2*(1-cn), vec(1)*vec(2)*(1-cn)-vec(3)*sn, vec(1)*vec(3)*(1-cn)+vec(2)*sn, 0; 
+    vec(1)*vec(2)*(1-cn)+vec(3)*sn, cn+vec(2)^2*(1-cn), vec(2)*vec(3)*(1-cn)-vec(1)*sn, 0; 
+    vec(1)*vec(3)*(1-cn)-vec(2)*sn, vec(2)*vec(3)*(1-cn)+vec(1)*sn, cn+vec(3)^2*(1-cn), 0; 
+    0 0 0 1];
+
+end