@thi.ng/shader-ast-stdlib/raymarch/ao.js

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

import { F, V3 } from "@thi.ng/shader-ast/api/types";
import { forLoop } 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 { FLOAT0, FLOAT05, FLOAT1, float } from "@thi.ng/shader-ast/ast/lit";
import {
  add,
  addSelf,
  inc,
  lte,
  mul,
  mulSelf,
  sub
} from "@thi.ng/shader-ast/ast/ops";
import { $x } from "@thi.ng/shader-ast/ast/swizzle";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import { clamp01 } from "../math/clamp.js";
const raymarchAO = (scene, numSamples = 5, name = gensym("raymarchAO_")) => defn(F, name, [V3, V3], (p, n) => {
  let r;
  let w;
  let d0;
  return [
    r = sym(FLOAT0),
    w = sym(FLOAT1),
    forLoop(
      sym(float(1)),
      (i) => lte(i, float(numSamples)),
      inc,
      (i) => [
        d0 = sym(mul(i, 1 / numSamples)),
        addSelf(r, mul(w, sub(d0, $x(scene(add(p, mul(n, d0))))))),
        mulSelf(w, FLOAT05)
      ]
    ),
    ret(sub(FLOAT1, clamp01(r)))
  ];
});
export {
  raymarchAO
};