atan2: Difference between revisions

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| ArcTangent of x/y. Used to determine the angle of a vector [x,y]. Result in [[Number#Degrees|Degrees]]. |= Description
| ArcTangent of ''x/y''. Used to determine the angle of a vector ''[x,y]''. Result in [[Number#Degrees|Degrees]].
 
<br>Note that this command can handle ''y'' being 0, unlike when using [[atan]], and will return 90 |= Description
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| [[Number]] |= Return value
| [[Number]]
 
<br><br>[[Image:atan.jpg|200px]]|= Return value  
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|x1= <pre>_xy=[5,3]; _degrees= (_xy select 0) atan2 (_xy select 1)</pre>
|x1= <code>_xy = [5,3];
_degrees= (_xy [[select]] 0) [[atan2]] (_xy [[select]] 1); //59.0362</code>|= Example 1


returns 59.0362 |= Example 1
|x2= Get direction from _obj1 to _obj2:<code>_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</code>|= Example 2
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| [[Math Commands]] |= See also
| [[atan]], [[Math Commands]] |= See also


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Revision as of 12:53, 15 June 2014

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.
Note that this command can handle y being 0, unlike when using atan, and will return 90
Groups:
Uncategorised

Syntax

Syntax:
Number = 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

Additional Information

See also:
atanMath 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

Notes

To get the direction of an object from the player:
_direction = ((getpos object select 0) - (getpos player select 0)) atan2 ((getpos object select 1) - (getpos player select 1));
_direction will be from -180 to 180
If positive values are needed then use:
if(_direction < 0) then {_direction = _direction + 360};

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