36 lines
1 KiB
GLSL
36 lines
1 KiB
GLSL
#include "../math/const.glsl"
|
|
#include "../space/scale.glsl"
|
|
|
|
/*
|
|
contributors: Patricio Gonzalez Vivo
|
|
description: Returns a star-shaped sdf with V branches
|
|
use: starSDF(<vec2> st, <int> V, <float> scale)
|
|
examples:
|
|
- https://raw.githubusercontent.com/patriciogonzalezvivo/lygia_examples/main/draw_shapes.frag
|
|
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_STARSDF
|
|
#define FNC_STARSDF
|
|
float starSDF(in vec2 st, in int V, in float s) {
|
|
#ifdef CENTER_2D
|
|
st -= CENTER_2D;
|
|
#else
|
|
st -= 0.5;
|
|
#endif
|
|
st *= 2.0;
|
|
float a = atan(st.y, st.x) / TAU;
|
|
float seg = a * float(V);
|
|
a = ((floor(seg) + 0.5) / float(V) +
|
|
mix(s, -s, step(0.5, fract(seg))))
|
|
* TAU;
|
|
return abs(dot(vec2(cos(a), sin(a)),
|
|
st));
|
|
}
|
|
|
|
float starSDF(in vec2 st, in int V) {
|
|
return starSDF( scale(st, 12.0/float(V)), V, 0.1);
|
|
}
|
|
#endif
|