@thi.ng/shader-ast-stdlib/sdf/polyhedra.js

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

import { F, V3 } from "@thi.ng/shader-ast/api/types";
import { defn, ret } from "@thi.ng/shader-ast/ast/function";
import { FLOAT0, PHI, vec3 } from "@thi.ng/shader-ast/ast/lit";
import { add, reciprocal, sub } from "@thi.ng/shader-ast/ast/ops";
import { abs, dot, max, pow } from "@thi.ng/shader-ast/builtin/math";
const __normalize = ([x, y, z]) => {
  const m = 1 / Math.hypot(x, y, z);
  return [x * m, y * m, z * m];
};
const phi = PHI.val;
const GDF = [
  [1, 0, 0],
  [0, 1, 0],
  [0, 0, 1],
  [1, 1, 1],
  [-1, 1, 1],
  [1, -1, 1],
  [1, 1, -1],
  [0, 1, phi + 1],
  [0, -1, phi + 1],
  [phi + 1, 0, 1],
  [-phi - 1, 0, 1],
  [1, phi + 1, 0],
  [-1, phi + 1, 0],
  [0, phi, 1],
  [0, -phi, 1],
  [1, 0, phi],
  [-1, 0, phi],
  [phi, 1, 0],
  [-phi, 1, 0]
].map((v) => vec3(...__normalize(v)));
const __defGDF = (id, vecs) => [
  defn(F, id, [V3, F], (p, r) => [
    ret(
      sub(
        vecs.reduce(
          (acc, v) => max(acc, abs(dot(p, v))),
          FLOAT0
        ),
        r
      )
    )
  ]),
  defn(F, id + "Smooth", [V3, F, F], (p, r, e) => [
    ret(
      sub(
        pow(
          vecs.reduce(
            (acc, v) => add(acc, pow(abs(dot(p, v)), e)),
            FLOAT0
          ),
          reciprocal(e)
        ),
        r
      )
    )
  ])
];
const [sdfOctahedron, sdfOctahedronSmooth] = __defGDF(
  "sdfOctahedron",
  GDF.slice(3, 7)
);
const [sdfDodecahedron, sdfDodecahedronSmooth] = __defGDF(
  "sdfDodecahedron",
  GDF.slice(13)
);
const [sdfIcosahedron, sdfIcosahedronSmooth] = __defGDF(
  "sdfIcosahedron",
  GDF.slice(3, 13)
);
const [sdfTruncatedOctahedron, sdfTruncatedOctahedronSmooth] = __defGDF(
  "sdfTruncatedOctahedron",
  GDF.slice(0, 7)
);
const [sdfTruncatedIcosahedron, sdfTruncatedIcosahedronSmooth] = __defGDF("sdfTruncatedIcosahedron", GDF.slice(3));
export {
  sdfDodecahedron,
  sdfDodecahedronSmooth,
  sdfIcosahedron,
  sdfIcosahedronSmooth,
  sdfOctahedron,
  sdfOctahedronSmooth,
  sdfTruncatedIcosahedron,
  sdfTruncatedIcosahedronSmooth,
  sdfTruncatedOctahedron,
  sdfTruncatedOctahedronSmooth
};