24 lines
No EOL
618 B
Text
24 lines
No EOL
618 B
Text
#include "../math/const.msl"
|
|
|
|
/*
|
|
description: generate the SDF of a icosahedron
|
|
use: <float> icosahedronSDF( <float3> pos, <float> size )
|
|
*/
|
|
|
|
#ifndef FNC_ICOSAHEDRONSDF
|
|
#define FNC_ICOSAHEDRONSDF
|
|
|
|
float icosahedronSDF(float3 p, float radius) {
|
|
float q = 2.61803398875; // Golden Ratio + 1 = (sqrt(5)+3)/2;
|
|
float3 n1 = normalize(float3(q, 1,0));
|
|
float3 n2 = float3(0.57735026919); // = sqrt(3)/3);
|
|
|
|
p = abs(p / radius);
|
|
float a = dot(p, n1.xyz);
|
|
float b = dot(p, n1.zxy);
|
|
float c = dot(p, n1.yzx);
|
|
float d = dot(p, n2) - n1.x;
|
|
return max(max(max(a,b),c)-n1.x,d) * radius;
|
|
}
|
|
|
|
#endif |