/**
 * Finds the entry plane of the first octant that a ray travels through.
 *
 * Determining the first octant requires knowing which of the t0s is the largest. The tms of the other axes must also be
 * compared against that largest t0.
 *
 * @param tx0 - Ray projection parameter.
 * @param ty0 - Ray projection parameter.
 * @param tz0 - Ray projection parameter.
 * @param txm - Ray projection parameter mean.
 * @param tym - Ray projection parameter mean.
 * @param tzm - Ray projection parameter mean.
 * @return The index of the first octant that the ray travels through.
 */
export declare function findEntryOctant(tx0: number, ty0: number, tz0: number, txm: number, tym: number, tzm: number): number;