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// ----------------------------------------------------------------------------
// Copyright (c) 2014, Nicolas P. Rougier. All Rights Reserved.
// Distributed under the (new) BSD License.
// ----------------------------------------------------------------------------
#include "arrows/util.glsl"
/* ---------------------------------------------------------
Computes the signed distance to an stealth arrow
Parameters:
-----------
texcoord : Point to compute distance to
body : Total length of the arrow (pixels, body+head)
head : Length of the head (pixels)
height : Height of the head (pixel)
linewidth: Stroke line width (in pixels)
antialias: Stroke antialiased area (in pixels)
Return:
-------
Signed distance to the arrow
--------------------------------------------------------- */
float arrow_stealth(vec2 texcoord,
float body, float head,
float linewidth, float antialias)
{
float w = linewidth/2.0 + antialias;
vec2 start = -vec2(body/2.0, 0.0);
vec2 end = +vec2(body/2.0, 0.0);
float height = 0.5;
// Head : 4 lines
float d1 = line_distance(texcoord, end-head*vec2(+1.0,-height),
end);
float d2 = line_distance(texcoord, end-head*vec2(+1.0,-height),
end-vec2(3.0*head/4.0,0.0));
float d3 = line_distance(texcoord, end-head*vec2(+1.0,+height), end);
float d4 = line_distance(texcoord, end-head*vec2(+1.0,+0.5),
end-vec2(3.0*head/4.0,0.0));
// Body : 1 segment
float d5 = segment_distance(texcoord, start, end - vec2(linewidth,0.0));
return min(d5, max( max(-d1, d3), - max(-d2,d4)));
}
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