import type { FnU4 } from "@thi.ng/api";
import type { ReadonlyVec } from "./api.js";
/**
 * Returns 6x the signed volume of the tetrahedron defined by given 3D points.
 *
 * @remarks
 * Returns positive or negative value if `d` lies below/above the plane defined
 * by a,b,c respectively (where "below" is defined such that a,b,c are
 * counterclockwise if viewed from above). Returns zero if all points are
 * coplanar.
 *
 * Based on code by Jonathan R. Shewchuk
 * http://www.cs.cmu.edu/afs/cs/project/quake/public/code/predicates.c
 *
 * @param a -
 * @param b -
 * @param c -
 * @param d -
 */
export declare const signedVolume: FnU4<ReadonlyVec, number>;
//# sourceMappingURL=signed-volume.d.ts.map