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// ----------------------------------------------------------------------------
// Copyright (c) 2014, Nicolas P. Rougier. All Rights Reserved.
// Distributed under the (new) BSD License.
// ----------------------------------------------------------------------------
/* ---------------------------------------------------------
Computes the signed distance from a line segment
Parameters:
-----------
p0, p1: Points describing the line segment
p: Point to measure distance from
Return:
-------
Signed distance
--------------------------------------------------------- */
float segment_distance(vec2 p, vec2 p1, vec2 p2) {
vec2 center = (p1 + p2) * 0.5;
float len = length(p2 - p1);
vec2 dir = (p2 - p1) / len;
vec2 rel_p = p - center;
float dist1 = abs(dot(rel_p, vec2(dir.y, -dir.x)));
float dist2 = abs(dot(rel_p, dir)) - 0.5*len;
return max(dist1, dist2);
}
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