@thi.ng/shader-ast-stdlib/tex/index-uv.js

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

import { I, V2 } from "@thi.ng/shader-ast/api/types";
import { defn, ret } from "@thi.ng/shader-ast/ast/function";
import { float, int, vec2 } from "@thi.ng/shader-ast/ast/lit";
import { add, div, modi, mul } from "@thi.ng/shader-ast/ast/ops";
import { $x, $y } from "@thi.ng/shader-ast/ast/swizzle";
const indexToUV = defn(
  V2,
  "indexToUV",
  [[I, "i", { prec: "highp" }], ["ivec2"]],
  (i, size) => [
    ret(
      vec2(
        div(float(modi(i, $x(size))), float($x(size))),
        div(float(div(i, $x(size))), float($y(size)))
      )
    )
  ]
);
const uvToIndex = defn(
  I,
  "uvToIndex",
  [V2, [I, "width", { prec: "highp" }]],
  (uv, width) => [
    ret(
      add(
        int(mul($x(uv), float(width))),
        int(mul($y(uv), float(mul(width, width))))
      )
    )
  ]
);
export {
  indexToUV,
  uvToIndex
};