/*

 * Copyright 2018, 2020-2021 Uber Technologies, Inc.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *         http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/** @file vec3d.c

 * @brief   3D floating point vector functions.

 */

#include "vec3d.h"

#include <math.h>

/**

 * Square of a number

 *

 * @param x The input number.

 * @return The square of the input number.

 */

double _square(double x) { return x * x; }

/**

 * Calculate the square of the distance between two 3D coordinates.

 *

 * @param v1 The first 3D coordinate.

 * @param v2 The second 3D coordinate.

 * @return The square of the distance between the given points.

 */

double _pointSquareDist(const Vec3d *v1, const Vec3d *v2) {

    return _square(v1->x - v2->x) + _square(v1->y - v2->y) +

           _square(v1->z - v2->z);

}

/**

 * Calculate the 3D coordinate on unit sphere from the latitude and longitude.

 *

 * @param geo The latitude and longitude of the point.

 * @param v The 3D coordinate of the point.

 */

void _geoToVec3d(const LatLng *geo, Vec3d *v) {

    double r = cos(geo->lat);

    v->z = sin(geo->lat);

    v->x = cos(geo->lng) * r;

    v->y = sin(geo->lng) * r;

}