1 %% Copyright (c) 2011, INRA
2 %% 2007-2011, David Legland <david.legland@grignon.inra.fr>
3 %% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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35 %% @deftypefn {Function File} {@var{pts} = } hexagonalGrid (@var{bounds}, @var{origin}, @var{size})
36 %% Generate hexagonal grid of points in the plane.
39 %% PTS = hexagonalGrid(BOUNDS, ORIGIN, SIZE)
40 %% generate points, lying in the window defined by BOUNDS (=[xmin ymin
41 %% xmax ymax]), starting from origin with a constant step equal to size.
42 %% SIZE is constant and is equals to the length of the sides of each
45 %% TODO: add possibility to use rotated grid
48 function varargout = hexagonalGrid(bounds, origin, size, varargin)
56 % consider two square grids with different centers
57 pts1 = squareGrid(bounds, origin + [0 0], [dx dy], varargin{:});
58 pts2 = squareGrid(bounds, origin + [dx/3 0], [dx dy], varargin{:});
59 pts3 = squareGrid(bounds, origin + [dx/2 dy/2], [dx dy], varargin{:});
60 pts4 = squareGrid(bounds, origin + [-dx/6 dy/2], [dx dy], varargin{:});
63 pts = [pts1;pts2;pts3;pts4];
68 % eventually compute also edges, clipped by bounds
69 % TODO : manage generation of edges
75 % find all x coordinate
76 x1 = bounds(1) + mod(x0-bounds(1), dx);
77 x2 = bounds(3) - mod(bounds(3)-x0, dx);
80 % horizontal edges : first find y's
81 y1 = bounds(2) + mod(y0-bounds(2), dy);
82 y2 = bounds(4) - mod(bounds(4)-y0, dy);
85 % number of points in each coord, and total number of points
89 if bounds(1)-x1+dx<size
90 disp('intersect bounding box');
95 edges = [edges;repmat(x2, [ny 1]) ly repmat(bounds(3), [ny 1]) ly];
103 tmpEdges(ind, 1) = lx;
104 tmpEdges(ind, 2) = ly(i);
105 tmpEdges(ind, 3) = lx+size;
106 tmpEdges(ind, 4) = ly(i);
107 edges = [edges; tmpEdges];
112 % process output arguments
117 varargout{2} = edges;