atan2

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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:
Uncategorised

Syntax

Syntax:
x atan2 y
Parameters:
x: Number
y: Number
Return Value:
Number

atan.jpg

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

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Notes

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.

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