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/**
* Copyright (c) Vispy Development Team
* Distributed under the (new) BSD License. See LICENSE.txt for more info.
*
* This files contains the code for drawing curved arrow heads.
*/
#include "arrowheads/util.glsl"
/**
* Computes the signed distance to an curved 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_curved(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;
vec2 p1 = start + size*vec2(0.0, -height);
vec2 p2 = start + size*vec2(0.0, +height);
vec2 p3 = end;
// Head : 3 circles
vec2 c1 = circle_from_2_points(p1, p3, 6.0*size).zw;
float d1 = length(texcoord - c1) - 6.0*size;
vec2 c2 = circle_from_2_points(p2, p3, 6.0*size).xy;
float d2 = length(texcoord - c2) - 6.0*size;
vec2 c3 = circle_from_2_points(p1, p2, 3.0*size).xy;
float d3 = length(texcoord - c3) - 3.0*size;
return -min(d3, min(d1,d2));
}
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