/**
* Create a cap given its axis and the cap opening angle, i.e. maximum angle
* between the axis and a point on the cap. 'axis' should be a unit-length
* vector, and 'angle' should be between 0 and 180 degrees.
*/
public static function fromAxisAngle(S2Point $axis, S1Angle $angle)
{
// The height of the cap can be computed as 1-cos(angle), but this isn't
// very accurate for angles close to zero (where cos(angle) is almost 1).
// Computing it as 2*(sin(angle/2)**2) gives much better precision.
// assert (S2.isUnitLength(axis));
$d = sin(0.5 * $angle->radians());
return new S2Cap($axis, 2 * $d * $d);
}
/**
* This is internal to avoid ambiguity about which units are expected.
* @param double|S1Angle $latRadians
* @param double|S1Angle $lngRadians
*/
public function __construct($latRadians = null, $lngRadians = null)
{
if ($latRadians instanceof S1Angle && $lngRadians instanceof S1Angle) {
$this->latRadians = $latRadians->radians();
$this->lngRadians = $lngRadians->radians();
} else {
if ($lngRadians === null && $latRadians instanceof S2Point) {
$this->latRadians = atan2($latRadians->z, sqrt($latRadians->x * $latRadians->x + $latRadians->y * $latRadians->y));
$this->lngRadians = atan2($latRadians->y, $latRadians->x);
} else {
if ($latRadians === null && $lngRadians === null) {
$this->latRadians = 0;
$this->lngRadians = 0;
} else {
$this->latRadians = $latRadians;
$this->lngRadians = $lngRadians;
}
}
}
}
public function greaterOrEquals(S1Angle $that)
{
return $this->radians() >= $that->radians();
}
