atan2

1.001.001.001.001.501.000.50

Hover & click on the images for description

Description

Description:

ArcTangent of x/y. Used to determine the angle of a vector [x,y]. Result in Degrees between -180 and 180.

ⓘ

This command can handle y being 0, unlike when using atan, and will return 90

⚠

Even though this command is a binary operator just like select command, it has higher precedence than select command, therefore the following expression:
_pos select 0 atan2 (_pos select 1)
will produce an error. The correct usage in this case will be:
(_pos select 0) atan2 (_pos select 1)

Groups:

Math - Geometry

Syntax

Syntax:

x atan2 y

Parameters:

x: Number

y: Number

Return Value:

Number

Examples

Example 1:

_xy = [5,3]; _degrees = (_xy select 0) atan2 (_xy select 1); // 59.0362

Example 2:

Get direction from _obj1 to _obj2:_vd = getPosASL _obj2 vectorDiff getPosASL _obj1; _dir = (_vd select 0) atan2 (_vd select 1); // _dir range from -180 to +180 if (_dir < 0) then {_dir = 360 + _dir}; // _dir range from 0 to 360

Example 3:

Get relative direction from _obj1 to _obj2:_xy = _obj1 worldToModel getPosASL _obj2; _dir = (_xy select 0) atan2 (_xy select 1); // _dir range from -180 to +180 if (_dir < 0) then {_dir = 360 + _dir}; // _dir range from 0 to 360

Additional Information

See also:

atantansincosasinacosradpivectorCosgetPosgetRelPosMath Commands

Notes

Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note

Posted on 08:00, 18 November 2009

KeV

To get the direction of an object from the player: _dir = ((getPos _obj select 0) - (getPos player select 0)) atan2 ((getPos _obj select 1) - (getPos player select 1)); //_dir will be from -180 to 180. If positive values are needed then use: if (_dir < 0) then {_dir = _dir + 360}; Or just use BIS_fnc_dirTo directly.