atan2

1.001.001.001.001.501.000.50

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Description

Description:

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

ⓘ

This command can handle x 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:

y atan2 x

Parameters:

y: Number

x: 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 _dir = (_dir + 360) % 360; // _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 _dir = (_dir + 360) % 360; // _dir range from 0 to 360

Additional Information

See also:

atan tan sin cos asin acos rad pi vectorCos getPos getRelPos Math Commands

Notes

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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.