Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / geom2d / intersectLineEdge.m

diff --git a/octave_packages/geometry-1.5.0/geom2d/intersectLineEdge.m b/octave_packages/geometry-1.5.0/geom2d/intersectLineEdge.m
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+++ b/octave_packages/geometry-1.5.0/geom2d/intersectLineEdge.m
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+%% Copyright (c) 2011, INRA
+%% 2003-2011, David Legland <david.legland@grignon.inra.fr>
+%% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+%%
+%% All rights reserved.
+%% (simplified BSD License)
+%%
+%% Redistribution and use in source and binary forms, with or without
+%% modification, are permitted provided that the following conditions are met:
+%%
+%% 1. Redistributions of source code must retain the above copyright notice, this
+%%    list of conditions and the following disclaimer.
+%%     
+%% 2. Redistributions in binary form must reproduce the above copyright notice, 
+%%    this list of conditions and the following disclaimer in the documentation
+%%    and/or other materials provided with the distribution.
+%%
+%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+%% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+%% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+%% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+%% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+%% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+%% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+%% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+%% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+%% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+%% POSSIBILITY OF SUCH DAMAGE.
+%%
+%% The views and conclusions contained in the software and documentation are
+%% those of the authors and should not be interpreted as representing official
+%% policies, either expressed or implied, of copyright holder.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{point} = } intersecLineEdge (@var{line}, @var{edge})
+%% Return intersection between a line and an edge.
+%%
+%%   Returns the intersection point of lines @var{line} and edge @var{edge}. 
+%%   @var{line} is a 1x4 array containing parametric representation of the line
+%%   (in the form [x0 y0 dx dy], see @code{createLine} for details). 
+%%   @var{edge} is a 1x4 array containing coordinates of first and second point
+%%   (in the form [x1 y1 x2 y2], see @code{createEdge} for details). 
+%%   
+%%   In case of colinear line and edge, returns [Inf Inf].
+%%   If line does not intersect edge, returns [NaN NaN].
+%%
+%%   If each input is [N*4] array, the result is a [N*2] array containing
+%%   intersections for each couple of edge and line.
+%%   If one of the input has N rows and the other 1 row, the result is a
+%%   [N*2] array.
+%%
+%%   @seealso{lines2d, edges2d, intersectEdges, intersectLine}
+%% @end deftypefn
+
+function point = intersectLineEdge(lin, edge)
+  x0 =  lin(:,1);
+  y0 =  lin(:,2);
+  dx1 = lin(:,3);
+  dy1 = lin(:,4);
+  x1 =  edge(:,1);
+  y1 =  edge(:,2);
+  x2 = edge(:,3);
+  y2 = edge(:,4);
+  dx2 = x2-x1;
+  dy2 = y2-y1;
+
+  N1 = length(x0);
+  N2 = length(x1);
+
+  % indices of parallel lines
+  par = abs(dx1.*dy2-dx2.*dy1)<1e-14;
+
+  % indices of colinear lines
+  col = abs((x1-x0).*dy1-(y1-y0).*dx1)<1e-14 & par ;
+
+  xi(col) = Inf;
+  yi(col) = Inf;
+  xi(par & ~col) = NaN;
+  yi(par & ~col) = NaN;
+
+  i = ~par;
+
+  % compute intersection points
+  if N1==N2
+         xi(i) = ((y1(i)-y0(i)).*dx1(i).*dx2(i) + x0(i).*dy1(i).*dx2(i) - x1(i).*dy2(i).*dx1(i)) ./ ...
+          (dx2(i).*dy1(i)-dx1(i).*dy2(i)) ;
+         yi(i) = ((x1(i)-x0(i)).*dy1(i).*dy2(i) + y0(i).*dx1(i).*dy2(i) - y1(i).*dx2(i).*dy1(i)) ./ ...
+          (dx1(i).*dy2(i)-dx2(i).*dy1(i)) ;
+  elseif N1==1
+         xi(i) = ((y1(i)-y0).*dx1.*dx2(i) + x0.*dy1.*dx2(i) - x1(i).*dy2(i).*dx1) ./ ...
+          (dx2(i).*dy1-dx1.*dy2(i)) ;
+         yi(i) = ((x1(i)-x0).*dy1.*dy2(i) + y0.*dx1.*dy2(i) - y1(i).*dx2(i).*dy1) ./ ...
+          (dx1.*dy2(i)-dx2(i).*dy1) ;
+  elseif N2==1
+         xi(i) = ((y1-y0(i)).*dx1(i).*dx2 + x0(i).*dy1(i).*dx2 - x1(i).*dy2.*dx1(i)) ./ ...
+          (dx2.*dy1(i)-dx1(i).*dy2) ;
+         yi(i) = ((x1-x0(i)).*dy1(i).*dy2 + y0(i).*dx1(i).*dy2 - y1(i).*dx2.*dy1(i)) ./ ...
+          (dx1(i).*dy2-dx2.*dy1(i)) ;
+  end
+
+  point   = [xi' yi'];
+  out     = find(~isPointOnEdge(point, edge));
+  point(out, :) = repmat([NaN NaN], [length(out) 1]);
+
+endfunction
+