@thi.ng/shader-ast-stdlib/light/trilight.js

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

import { V3 } from "@thi.ng/shader-ast/api/types";
import { defn, ret } from "@thi.ng/shader-ast/ast/function";
import { FLOAT0, FLOAT1 } from "@thi.ng/shader-ast/ast/lit";
import { add, mul, neg, sub } from "@thi.ng/shader-ast/ast/ops";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import { abs, dot, max } from "@thi.ng/shader-ast/builtin/math";
const trilight = defn(
  V3,
  "trilight",
  [V3, V3, V3, V3, V3],
  (n, l, c1, c2, c3) => {
    let d;
    return [
      d = sym(dot(n, l)),
      ret(
        add(
          add(mul(c1, max(d, FLOAT0)), mul(c2, sub(FLOAT1, abs(d)))),
          mul(c3, max(dot(neg(n), l), FLOAT0))
        )
      )
    ];
  }
);
export {
  trilight
};