stroke.msl

/*
contributors: Patricio Gonzalez Vivo
description: Fill a stroke a SDF. From PixelSpiritDeck https://github.com/patriciogonzalezvivo/PixelSpiritDeck
use: stroke(<float> sdf, <float> size, <float> width [, <float> edge])
license:
    - Copyright (c) 2021 Patricio Gonzalez Vivo under Prosperity License - https://prosperitylicense.com/versions/3.0.0
    - Copyright (c) 2021 Patricio Gonzalez Vivo under Patron License - https://lygia.xyz/license
*/

#ifndef FNC_STROKE
#define FNC_STROKE

#include "../math/aastep.msl"
#include "../math/saturate.msl"

float stroke(float x, float size, float w) {
    float d = aastep(size, x + w * 0.5) - aastep(size, x - w * 0.5);
    return saturate(d);
}

float stroke(float x, float size, float w, float edge) {
    float d = smoothstep(size - edge, size + edge, x + w * 0.5) - smoothstep(size - edge, size + edge, x - w * 0.5);
    return saturate(d);
}

#endif