Code covered by the BSD License

# geom2d

### David Legland (view profile)

13 Jun 2005 (Updated )

Geometry library for matlab. Performs geometric computations on points, lines, circles, polygons...

onRay(point, ray)
```function b = onRay(point, ray)
%ONRAY test if a point belongs to a ray
%
%   B = onRay(PT, RAY);
%   Returns 1 if point PT belongs to the ray RAY.
%   PT is given by [x y] and RAY by [x0 y0 dx dy].
%
%   rays2d, points2d, onLine
%
%   ---------
%   author : David Legland
%   INRA - TPV URPOI - BIA IMASTE
%   created the 31/10/2003.
%

%   HISTORY
%   07/07/2005 : normalize condition to test if on the line
%       and add support of multiple rays or points
%   22/05/2009 deprecate

% deprecation warning
warning('geom2d:deprecated', ...
'''onRay'' is deprecated, use ''isPointOnRay'' instead');

% number of rays and points
Nr = size(line, 1);
Np = size(point, 1);

% if several rays or several points, adapt sizes of arrays
x0 = repmat(ray(:,1)', Np, 1);
y0 = repmat(ray(:,2)', Np, 1);
dx = repmat(ray(:,3)', Np, 1);
dy = repmat(ray(:,4)', Np, 1);
xp = repmat(point(:,1), 1, Nr);
yp = repmat(point(:,2), 1, Nr);

% test if points belongs to the ray
b1 = abs((xp-x0).*dy-(yp-y0).*dx)./sqrt(dx.*dx+dy.*dy) < 1e-13;

% check if points lie the good direction on the rays
ind = abs(dx)>abs(dy);
t = zeros(size(b1));
t(ind) = (xp(ind)-x0(ind))./dx(ind);
t(~ind) = (yp(~ind)-y0(~ind))./dy(~ind);

% combine the two tests
b = b1 && (t>0);
```