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// ----------------------------------------------------------------------------
// Copyright (c) 2014, Nicolas P. Rougier. All Rights Reserved.
// Distributed under the (new) BSD License.
// ----------------------------------------------------------------------------
/* ---------------------------------------------------------
Project a point p onto a line (p0,p1) and return linear position u such that
p' = p0 + u*(p1-p0)
Parameters:
-----------
p0, p1: Points describing the line
p: Point to be projected
Return:
-------
Linear position of p onto (p0,p1)
--------------------------------------------------------- */
float point_to_line_projection(vec2 p0, vec2 p1, vec2 p)
{
// Projection p' of p such that p' = p0 + u*(p1-p0)
// Then u *= lenght(p1-p0)
vec2 v = p1 - p0;
float l = length(v);
return ((p.x-p0.x)*v.x + (p.y-p0.y)*v.y) / l;
}
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