atan2: Difference between revisions

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{{RV|type=command
{{RV|type=command


| ofp
|game1= ofp
|version1= 1.00


|1.00
|game2= ofpe
|version2= 1.00


|gr1= Math - Geometry
|game3= arma1
|version3= 1.00
 
|game4= arma2
|version4= 1.00


| ArcTangent of ''x/y''. Used to determine the angle of a vector ''[x,y]''. Result in [[Number#Degrees|Degrees]] between -180 and 180.
|game5= arma2oa
<br><br>
|version5= 1.50
{{Feature | Informative | This command can handle ''y'' being 0, unlike when using [[atan]], and will return 90 }}
<br>
{{Feature | important | Even though this command is a binary operator just like [[select]] command, it has [[SQF Syntax#Rules_of_Precedence | higher precedence]] than [[select]] command, therefore the following expression: <br><tt>_pos select 0 [[atan2]] (_pos select 1)</tt><br> will produce an error. The correct usage in this case will be: <br><tt>(_pos select 0) [[atan2]] (_pos select 1)</tt>}}


| x '''atan2''' y
|game6= tkoh
|version6= 1.00


|p1= x: [[Number]]
|game7= arma3
|version7= 0.50


|p2= y: [[Number]]
|gr1= Math - Geometry


| [[Number]]  
|descr= [[File:atan.jpg|right|300px]] ArcTangent of ''y/x''. Used to determine the angle of a vector ''[y,x]''. Result in [[Number#Degrees|Degrees]] between -180 and 180.
{{Feature|informative|This command can handle ''x'' being 0, unlike when using [[atan]], and will return 90}}
{{Feature|important|
This command has [[SQF Syntax#Rules of Precedence|higher precedence]] than the [[select]] command, therefore beware of the case below:
<sqf notrim>
_pos select 0  atan2 (_pos select 1) // error
(_pos select 0) atan2 (_pos select 1) // OK
</sqf>


<br><br>[[Image:atan.jpg|200px]]
Alternatively, consider using the [[a hash b|#]] operator: <sqf inline>_pos # 0 atan2 _pos # 1</sqf>
 
}}
|x1= <code>_xy = [5,3];
_degrees = (_xy [[select]] 0) [[atan2]] (_xy [[select]] 1); //59.0362</code>


|x2= Get direction from _obj1 to _obj2:<code>_vd = [[getPosASL]] _obj2 [[vectorDiff]] [[getPosASL]] _obj1;
|s1= y [[atan2]] x
_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>


|x3= Get relative direction from _obj1 to _obj2:<code>_xy = _obj1 [[worldToModel]] [[getPosASL]] _obj2;
|p1= y: [[Number]]
_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</code>


|seealso= [[atan]], [[tan]], [[sin]], [[cos]], [[asin]], [[acos]], [[rad]], [[pi]], [[vectorCos]], [[getPos]], [[getRelPos]], [[Math Commands]]
|p2= x: [[Number]]
}}
 
|r1= [[Number]]


<dl class="command_description">
|x1= <sqf>
<!-- Note Section BEGIN -->
_yx = [5,3];
<dd class="notedate">Posted on 08:00, 18 November 2009</dd>
_degrees = (_yx select 0) atan2 (_yx select 1); // 59.0362
<dt class="note">[[User:KeV|KeV]]<dd class="note">
</sqf>
To get the direction of an object from the player:
<code>_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.
</code>
If positive values are needed then use:
<code>[[if]] (_dir < 0) [[then]] {_dir = _dir + 360};
</code>
Or just use [[BIS_fnc_dirTo]] directly.
<!-- Note Section END -->
</dl>


|x2= Get direction from _obj1 to _obj2:
<sqf>
_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
</sqf>


|x3= Get relative direction from _obj1 to _obj2:
<sqf>
_yx = _obj1 worldToModel getPosASL _obj2;
_dir = (_yx select 0) atan2 (_yx select 1); // _dir range from -180 to +180
_dir = (_dir + 360) % 360; // _dir range from 0 to 360
</sqf>


[[Category:Scripting Commands OFP 1.99|ATAN2]]
|seealso= [[atan]] [[tan]] [[sin]] [[cos]] [[asin]] [[acos]] [[rad]] [[pi]] [[vectorCos]] [[BIS_fnc_dirTo]] [[getRelPos]] [[getRelDir]]
[[Category:Scripting Commands OFP 1.96|ATAN2]]
}}
[[Category:Scripting Commands OFP 1.46|ATAN2]]
{{GameCategory|arma1|Scripting Commands}}
{{GameCategory|arma2|Scripting Commands}}
{{GameCategory|arma3|Scripting Commands}}
{{GameCategory|tkoh|Scripting Commands}}

Latest revision as of 09:38, 25 March 2024

Logo A0.png1.00ofpe logo.png1.00Logo A1 black.png1.00Logo A2.png1.00A2 OA Logo.png1.50tkoh logo small.png1.00Arma 3 logo black.png0.50
Hover & click on the images for description

Description

Description:
atan.jpg
ArcTangent of y/x. Used to determine the angle of a vector [y,x]. Result in Degrees between -180 and 180.
ⓘ
This command can handle x being 0, unlike when using atan, and will return 90
⚠
This command has higher precedence than the select command, therefore beware of the case below:

_pos select 0 atan2 (_pos select 1) // error (_pos select 0) atan2 (_pos select 1) // OK

Alternatively, consider using the # operator: _pos # 0 atan2 _pos # 1
Groups:
Math - Geometry

Syntax

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

Examples

Example 1:
_yx = [5,3]; _degrees = (_yx select 0) atan2 (_yx 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:
_yx = _obj1 worldToModel getPosASL _obj2; _dir = (_yx select 0) atan2 (_yx 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 BIS_fnc_dirTo getRelPos getRelDir

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
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