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//-----------------------------------------------------------------------------
// Edge rendering shader
//
// Copyright 2016 Aleksey Egorov
//-----------------------------------------------------------------------------
const float feather = 0.5;
uniform vec4 color;
uniform float pixel;
uniform float width;
uniform float patternLen;
uniform float patternScale;
uniform sampler2D pattern;
varying vec3 fragLoc;
void main() {
// lookup distance texture
vec4 v = texture2D(pattern, vec2(fragLoc.z / patternScale, 0.0));
// decode distance value
float val = dot(v, vec4(1.0, 1.0 / 255.0, 1.0 / 65025.0, 1.0 / 160581375.0));
// calculate cap
float dist = length(vec2(val * patternScale / (patternLen * width) + abs(fragLoc.x), fragLoc.y));
// perform antialiasing
float k = smoothstep(1.0 - 2.0 * feather * pixel / (width + feather * pixel), 1.0, abs(dist));
// perform alpha-test
if(k == 1.0) discard;
// write resulting color
gl_FragColor = vec4(color.rgb, color.a * (1.0 - k));
}
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