simplex3.ts

// SPDX-License-Identifier: Apache-2.0
import type { Vec3Sym, Vec4Sym } from "@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 { defn, ret } from "@thi.ng/shader-ast/ast/function";
import {
	FLOAT0,
	FLOAT05,
	FLOAT1,
	FLOAT2,
	float,
	vec2,
	vec3,
	vec4,
} from "@thi.ng/shader-ast/ast/lit";
import { add, mul, mulSelf, neg, sub } from "@thi.ng/shader-ast/ast/ops";
import { $, $w, $x, $xy, $y, $z } from "@thi.ng/shader-ast/ast/swizzle";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import {
	abs,
	dot,
	floor,
	max,
	min,
	mod,
	step,
} from "@thi.ng/shader-ast/builtin/math";
import { permute4 } from "./permute.js";

export const snoise3 = defn(F, "snoise3", [V3], (v) => {
	let g: Vec3Sym;
	let j: Vec4Sym;
	let l: Vec3Sym;
	let m: Vec4Sym;
	let p: Vec4Sym;
	let norm: Vec4Sym;
	let _x: Vec4Sym;
	let x: Vec4Sym;
	let y: Vec4Sym;
	let h: Vec4Sym;
	let sh: Vec4Sym;
	let a0: Vec4Sym;
	let a1: Vec4Sym;
	let b0: Vec4Sym;
	let b1: Vec4Sym;
	let x0: Vec3Sym;
	let x1: Vec3Sym;
	let x2: Vec3Sym;
	let x3: Vec3Sym;
	let p0: Vec3Sym;
	let p1: Vec3Sym;
	let p2: Vec3Sym;
	let p3: Vec3Sym;
	let i: Vec3Sym;
	let i1: Vec3Sym;
	let i2: Vec3Sym;
	const NS = 1 / 7;
	const NSX = NS * 2;
	const NSY = NS * 0.5 - 1;
	return [
		(i = sym(floor(add(v, dot(v, vec3(1 / 3)))))),
		(x0 = sym(add(sub(v, i), dot(i, vec3(1 / 6))))),
		(g = sym(step($(x0, "yzx"), x0))),
		(l = sym($(sub(FLOAT1, g), "zxy"))),
		(i1 = sym(min(g, l))),
		(i2 = sym(max(g, l))),
		(x1 = sym(add(sub(x0, i1), 1 / 6))),
		(x2 = sym(add(sub(x0, i2), 1 / 3))),
		(x3 = sym(sub(x0, FLOAT05))),
		assign(i, mod(i, float(289))),
		(p = sym(
			permute4(
				add(
					permute4(
						add(
							permute4(
								add(vec4(FLOAT0, $z(i1), $z(i2), FLOAT1), $z(i))
							),
							add(vec4(FLOAT0, $y(i1), $y(i2), FLOAT1), $y(i))
						)
					),
					add(vec4(FLOAT0, $x(i1), $x(i2), FLOAT1), $x(i))
				)
			)
		)),
		(j = sym(sub(p, mul(floor(mul(p, NS * NS)), 49)))),
		(_x = sym(floor(mul(j, NS)))),
		(x = sym(add(mul(_x, NSX), NSY))),
		(y = sym(add(mul(floor(sub(j, mul(_x, 7))), NSX), NSY))),
		(h = sym(sub(sub(FLOAT1, abs(x)), abs(y)))),
		(sh = sym(neg(step(h, vec4())))),
		(b0 = sym(vec4($xy(x), $xy(y)))),
		(b1 = sym(vec4($(x, "zw"), $(y, "zw")))),
		(a0 = sym(
			add(
				$(b0, "xzyw"),
				mul(
					$(add(mul(floor(b0), FLOAT2), FLOAT1), "xzyw"),
					$(sh, "xxyy")
				)
			)
		)),
		(a1 = sym(
			add(
				$(b1, "xzyw"),
				mul(
					$(add(mul(floor(b1), FLOAT2), FLOAT1), "xzyw"),
					$(sh, "zzww")
				)
			)
		)),
		(p0 = sym(vec3($xy(a0), $x(h)))),
		(p1 = sym(vec3($(a0, "zw"), $y(h)))),
		(p2 = sym(vec3($xy(a1), $z(h)))),
		(p3 = sym(vec3($(a1, "zw"), $w(h)))),
		(norm = sym(
			sub(
				1.79284291400159,
				mul(
					vec4(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)),
					0.85373472095314
				)
			)
		)),
		mulSelf(p0, $x(norm)),
		mulSelf(p1, $y(norm)),
		mulSelf(p2, $z(norm)),
		mulSelf(p3, $w(norm)),
		(m = sym(
			max(
				vec4(),
				sub(
					0.6,
					vec4(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3))
				)
			)
		)),
		mulSelf(m, m),
		ret(
			mul(
				42,
				dot(
					mul(m, m),
					vec4(dot(p0, x0), dot(p1, x1), dot(p2, x2), dot(p3, x3))
				)
			)
		),
	];
});

export const snoiseVec32 = defn(V2, "snoiseVec32", [V3], (p) => {
	return [
		ret(
			vec2(
				snoise3(p),
				snoise3(
					vec3(sub($y(p), 19.1), add($z(p), 33.4), add($x(p), 47.2))
				)
			)
		),
	];
});

export const snoiseVec3 = defn(V3, "snoiseVec3", [V3], (p) => {
	return [
		ret(
			vec3(
				snoise3(p),
				snoise3(
					vec3(sub($y(p), 19.1), add($z(p), 33.4), add($x(p), 47.2))
				),
				snoise3(
					vec3(add($z(p), 74.2), sub($x(p), 124.5), add($y(p), 99.4))
				)
			)
		),
	];
});