@thi.ng/shader-ast-stdlib/noise/worley2.js

Function collection for modular GPGPU / shader programming with @thi.ng/shader-ast

import { F, V2, V3 } from "@thi.ng/shader-ast/api/types";
import { assign } from "@thi.ng/shader-ast/ast/assign";
import { ternary } from "@thi.ng/shader-ast/ast/controlflow";
import { defn, ret } from "@thi.ng/shader-ast/ast/function";
import { gensym } from "@thi.ng/shader-ast/ast/idgen";
import { float, vec3 } from "@thi.ng/shader-ast/ast/lit";
import { add, lt, mul, sub } from "@thi.ng/shader-ast/ast/ops";
import { $, $x, $xy, $y, $z } from "@thi.ng/shader-ast/ast/swizzle";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import {
  abs,
  floor,
  fract,
  max,
  min,
  mod,
  sqrt
} from "@thi.ng/shader-ast/builtin/math";
import { permute3 } from "./permute.js";
const worleyDist = defn(V3, "worleyDist", [V3, V3], (a, b) => [
  ret(add(mul(a, a), mul(b, b)))
]);
const worleyDistManhattan = defn(
  V3,
  "worleyDistManhatten",
  [V3, V3],
  (a, b) => [ret(add(abs(a), abs(b)))]
);
const worley2 = (distFn, name = gensym("worley2_")) => defn(V2, name, [V2, F], (P, jitter) => {
  const K = float(1 / 7);
  const Ko = float(3 / 7);
  const oI = sym(vec3(-1, 0, 1));
  const oF = sym(vec3(-0.5, 0.5, 1.5));
  let pI;
  let pF;
  let px;
  let p;
  let d1;
  let d2;
  let d3;
  let d1a;
  const $dist = (x) => distFn(
    add(add($x(pF), x), mul(sub(fract(mul(p, K)), Ko), jitter)),
    add(
      sub($y(pF), oF),
      mul(
        sub(mul(mod(floor(mul(p, K)), float(7)), K), Ko),
        jitter
      )
    )
  );
  return [
    oI,
    oF,
    pI = sym(mod(floor(P), float(289))),
    pF = sym(fract(P)),
    px = sym(permute3(add(oI, $x(pI)))),
    p = sym(permute3(add(add(oI, $y(pI)), $x(px)))),
    d1 = sym($dist(0.5)),
    assign(p, permute3(add(oI, add($y(pI), $y(px))))),
    d2 = sym($dist(-0.5)),
    assign(p, permute3(add(oI, add($y(pI), $z(px))))),
    d3 = sym($dist(-1.5)),
    d1a = sym(min(d1, d2)),
    assign(d2, min(max(d1, d2), d3)),
    assign(d1, min(d2, d1a)),
    assign(d2, max(d2, d1a)),
    assign($xy(d1), ternary(lt($x(d1), $y(d1)), $xy(d1), $(d1, "yx"))),
    assign(
      $(d1, "xz"),
      ternary(lt($x(d1), $z(d1)), $(d1, "xz"), $(d1, "zx"))
    ),
    assign($(d1, "yz"), min($(d1, "yz"), $(d2, "yz"))),
    assign($y(d1), min(min($y(d1), $z(d1)), $x(d2))),
    ret(sqrt($xy(d1)))
  ];
});
export {
  worley2,
  worleyDist,
  worleyDistManhattan
};