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galaxy.php
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<?php
/**
* Geo galaxy class.
*
* Zed. The immensity of stars. The HyperShip. The people.
*
* (c) 2010, Dereckson, some rights reserved.
* Released under BSD license.
*
* A 3D grid of objects
*
* 0.1 2010-02-08 14:02 Initial version [DcK]
* 0.2 2010-07-25 9:20 Spherical conversion, get objects
*
* @package Zed
* @subpackage Geo
* @author Sébastien Santoro aka Dereckson <dereckson@espace-win.org>
* @copyright 2010 Sébastien Santoro aka Dereckson
* @license http://www.opensource.org/licenses/bsd-license.php BSD
* @version 0.1
* @link http://scherzo.dereckson.be/doc/zed
* @link http://zed.dereckson.be/
* @filesource
*/
/**
* Geo galaxy class
*
* This class provides methods to convert coordinate polars.
*
* @todo create a unit testing file dev/tests/GeoGalaxyTest.php
* @todo add unit testing for the normalizeAngle method in dev/tests/GeoGalaxyTest.php
*/
class GeoGalaxy {
/*
* ----------------------------------------------------------------------- *
* Objects fetchers
* ----------------------------------------------------------------------- *
*/
/**
* Gets all the coordinates of the objects in the galaxy.
*
* @return array An array of array. Each item is [string object_name, string object_type, GeoPoint3D coordinates]
*/
static function getCoordinates () {
global $db;
$sql = "SELECT * FROM geo_coordinates";
if (!$result = $db->sql_query($sql)) message_die(SQL_ERROR, "Can't query geo_coordinates view.", '', __LINE__, __FILE__, $sql);
$objects = array();
while ($row = $db->sql_fetchrow($result)) {
//Demios ship xyz: [-50, 30, 40]
//Kaos asteroid xyz: [150, -129, 10]
$objects[] = array($row[0], $row[1], GeoPoint3D::fromString($row[2]));
}
return $objects;
}
/*
* ----------------------------------------------------------------------- *
* Helper methods - math
* ----------------------------------------------------------------------- *
*/
/**
* Normalizes an angle, so 0 =< angle < 2 PI
*
* @param float $angle angle in radians (use deg2rad() if you've degrees)
* @return an angle in the 0 =< angle < 2 PI interval
*/
static function normalizeAngle ($angle) {
while ($angle < 0) {
$angle += 2 * M_PI;
}
while ($angle >= 2 * M_PI) {
$angle -= 2 * M_PI;
}
return $angle;
}
/**
* Converts (x, y, z) cartesian to (ρ, φ, θ) spherical coordinates
*
* The algo used is from http://fr.wikipedia.org/wiki/Coordonn%C3%A9es_sph%C3%A9riques#Relation_avec_les_autres_syst.C3.A8mes_de_coordonn.C3.A9es_usuels
*
* @param int $x the x coordinate
* @param int $y the y coordinate
* @param int $z the z coordinate
* @return array an array of 3 floats number, representing the (ρ, φ, θ) spherical coordinates
*/
static function cartesianToSpherical ($x, $y, $z) {
$rho = sqrt($x * $x + $y * $y + $z * $z); //ρ = sqrt(x² + y² + z²)
$theta= acos($z / $rho); //φ = acos z/φ
$phi = acos($x / sqrt($x * $x + $y * $y)); //θ = acos x / sqrt(x² + y²)
if (y < 0) $phi = 2 * M_PI - $phi; //∀ y < 0 θ = 2π - θ
return array(round($rho, 2), round(rad2deg($theta), 2), round(rad2deg($phi), 2));
}
/**
* Converts (x, y, z) cartesian to (ρ, φ, θ) spherical coordinates
*
* The algo used is from http://www.phy225.dept.shef.ac.uk/mediawiki/index.php/Cartesian_to_polar_conversion
*
* @param int $x the x coordinate
* @param int $y the y coordinate
* @param int $z the z coordinate
* @return array an array of 3 floats number, representing the (ρ, φ, θ) spherical coordinates
*/
static function cartesianToSphericalAlternative ($x, $y, $z) {
$rho = sqrt($x * $x + $y * $y + $z * $z); //ρ = sqrt(x² + y² + z²)
$theta= atan2($y, $x); //φ = atan2 $y $x
$phi = acos($z / $rho); //θ = acos z/φ
return array(round($rho, 2), round(rad2deg($theta), 2), round(rad2deg($phi), 2));
}
}

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