function (groundBody, groundNormal) {
    let ray,
        hitNormal,
        vFrom = this.body.position,
        vTo = this.body.position.clone();

    ray = new CANNON.Ray(vFrom, vTo);
    ray._updateDirection(); // TODO - Report bug.
    ray.intersectBody(groundBody);

    if (!ray.hasHit) return groundNormal;

    // Compare ABS, in case we're projecting against the inside of the face.
    hitNormal = ray.result.hitNormalWorld;
    return Math.abs(hitNormal.y) > Math.abs(groundNormal.y) ? hitNormal : groundNormal;
  }