@thi.ng/shader-ast-stdlib/raymarch/normal.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 { gensym } from "@thi.ng/shader-ast/ast/idgen";
import { vec2, vec3 } from "@thi.ng/shader-ast/ast/lit";
import { add, sub } from "@thi.ng/shader-ast/ast/ops";
import { $, $x } from "@thi.ng/shader-ast/ast/swizzle";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import { normalize } from "@thi.ng/shader-ast/builtin/math";
const raymarchNormal = (scene, name = gensym("raymarchNormal_")) => defn(V3, name, [V3, F], (p, smooth) => {
  let dn;
  const comp = (id) => sub($x(scene(add(p, $(dn, id)))), $x(scene(sub(p, $(dn, id)))));
  return [
    dn = sym(vec2(smooth, 0)),
    ret(normalize(vec3(comp("xyy"), comp("yxy"), comp("yyx"))))
  ];
});
export {
  raymarchNormal
};