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/**
* Copyright (c) Vispy Development Team
* Distributed under the (new) BSD License. See LICENSE.txt for more info.
*
* This file contains the code for drawing "stealth" type arrow heads.
*/
#include "arrowheads/util.glsl"
/**
* Computes the signed distance to an stealth arrow
*
* Parameters:
* -----------
*
* texcoord
* Point to compute distance to
* size
* Size of the arrow head in pixels
* linewidth
* Width of the line
* antialias
* Anti alias width
*
* Return:
* -------
* Signed distance to the arrow
*/
float arrow_stealth(vec2 texcoord, float size,
float linewidth, float antialias)
{
vec2 start = -vec2(size/2.0, 0.0);
vec2 end = +vec2(size/2.0, 0.0);
float height = 0.5;
// Head : 4 lines
float d1 = line_distance(texcoord, start + size*vec2(0.0, +height), end);
float d2 = line_distance(texcoord, start + size*vec2(0.0, +height),
start + size*vec2(0.3, 0.0));
float d3 = line_distance(texcoord, start + size*vec2(0.0, -height), end);
float d4 = line_distance(texcoord, start + size*vec2(0.0, -height),
start + size*vec2(0.25, 0.0));
return max( max(-d1, d3), - max(-d2,d4));
}
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