getPos: Difference between revisions

Revision as of 14:37, 8 December 2021

1.00

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Description

Description:

Returns object or location position. If the argument is an object, the return value is in format PositionAGLS.
The alternative syntax gets the position given distance and heading away from provided object or position - the command equivalent of BIS_fnc_relPos.

⚠

Do not use this command to get an object's position in 3D format:

the Z value from this command is relative to the surface underneath, and there is no compatible setter command to use it with;
the commonly misused code: _obj1 setPos getPos _obj2 is absolutely wrong
this command is significantly slower than other position commands because it has to calculate the surface below a position from objects in the (2D) area; its performance therefore suffers from areas with a high density of objects such as cities, and can easily be ~20x slower than other, simpler position commands - see this benchmark.

The only correct usage of this command is to determine the altitude of an object from the surface below it (see Example 5).

Groups:

Positions

Syntax 1

Syntax:: getPos object
Parameters:: object: Object
Return Value:: Array format PositionAGLS where Z is the height over the surface underneath

Syntax 2

Syntax:: getPos location
Parameters:: location: Location
Return Value:: Array format [x,y,z], where Z is -1 * getTerrainHeightASL at the location

1.56

Syntax 3

Syntax:: origin getPos [distance, heading]
Parameters:: origin: Object, Position2D or Position3D
: distance: Number - distance from position
: heading: Number - in which compass direction
Return Value:: Array - format [x,y,z], where z is land surface position in format PositionAGL

Examples

Example 1:: hintSilent str getPos player;
Example 2:: getPos vs. other methods (over sea). Pay attention to Z values: getPos ship; // [2412.01, 6036.33, -0.839965] getPosATL ship; // [2412.01, 6036.33, 19.4266] getPosASL ship; // [2412.01, 6036.33, -0.920066] getPosASLW ship; // [2412.01, 6036.33, -0.865981] visiblePosition ship; // [2412.02, 6036.33, -0.837952] visiblePositionASL ship; // [2412.02, 6036.33, -0.91798] position ship; // [2412.01, 6036.33, -0.839965]
Example 3:: getPos vs. other methods (over land, on top of a 100m high building). Pay attention to Z values: getPos car; // [2508.64, 5681.47, 0.0609589] getPosATL car; // [2508.64, 5681.47, 100.0356369] getPosASL car; // [2508.64, 5681.47, 171.718] getPosASLW car; // [2508.64, 5681.47, 171.718] visiblePosition car; // [2508.64, 5681.47, 0.0609512] visiblePositionASL car; // [2508.64, 5681.47, 171.718] position car; // [2508.64, 5681.47, 0.0609589]
Example 4:: Find position 100 metres and 45 degrees from player position:player getPos [100, 45];
Example 5:: Determine if a free-falling unit is close enough to the surface (including buildings, aircraft carriers etc) below to deploy the parachute: waitUntil { sleep 1; getPos player select 2 < 200 }; hint "Deploying a parachute might be a good idea";

Additional Information

See also:: getPosVisual getRelPos setPos setPosAGLS position getPosATL getPosASL getPosASLW visiblePosition visiblePositionASL getMarkerPos

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 16 Feb, 2007
Dr_Eyeball: getPos obj select 2 might return the vertical position above ground level, but for a stacked object, it returns the vertical position above the object beneath it. The same problem existed for getPosASL (pre-Arma 2 games only). There was a discussion _{(dead link)} thread in the BIS forums which suggested the use of the command modelToWorld instead to get around this issue where an absolute vertical position is required. ArmA Ver 1.02.

: Posted on 23 Nov, 2011
Tankbuster: You can use getPos and setPos on triggers.

@@ Line 26: / Line 26: @@
 |gr1= Positions
-|descr= Returns object or location position. If the argument is the object, the return value is in format [[PositionAGLS]]. Z value is height over the surface underneath.<br>
+|descr= Returns object or location position. If the argument is an object, the return value is in format [[PositionAGLS]].<br>
-The alternative syntax gets the position given distance and heading away from provided object or position - the equivalent of [[BIS_fnc_relPos]].
+The alternative syntax gets the position given distance and heading away from provided object or position - the command equivalent of [[BIS_fnc_relPos]].
-{{Feature | Important | Do not use this command to get an object's position in 3D format, as the Z value from this command is '''relative''' to the surface underneath, and there is no compatible setter command to use it with. Therefore the commonly misused code: {{ic|_obj1 [[setPos]] [[getPos]] _obj2}} is '''absolutely wrong'''.}}
-{{Feature | Informative | The only '''correct''' use case for this command is to determine the placement height of an object. For example, to determine if a free-falling unit is close enough to the surface (including buildings) to deploy the parachute:
+{{Feature|important|
-<code>[[waitUntil]] {([[getPos]] _parachute) [[select]] 2 [[a_less_b|<]] 200}; {{cc|deploy the parachute now!}}</code>}}
+Do '''not''' use this command to get an object's position in 3D format:
-{{Feature | Important | This command is significantly '''slower''' than other position commands, because it has to calculate the surface below a position. The performance difference depends on object density near the position (in 2D). In areas where a lot of detailed objects are present (e.g. towns), this command can be easily ~20x slower than others. See [[Code_Optimisation#getPos.2A_and_setPos.2A|this page]] for a performance comparison between various position commands.}}
+* the Z value from this command is '''relative''' to the surface underneath, and there is no compatible setter command to use it with;<br>the commonly misused code: {{ic|_obj1 [[setPos]] [[getPos]] _obj2}} is '''absolutely wrong'''
+* this command is significantly '''slower''' than other [[:Category:Command Group: Positions|position commands]] because it has to calculate the surface below a position from objects in the (2D) area; its performance therefore suffers from areas with a high density of objects such as cities, and can easily be ~20x slower than other, simpler position commands - see [[Code Optimisation#getPos.2A and setPos.2A|this benchmark]].
+The '''only''' correct usage of this command is to determine the altitude of an object '''from the surface below it''' (see {{HashLink|#Example 5}}).
+}}
 |s1= [[getPos]] object
 |p1= object: [[Object]]
-|r1= [[Array]] - format [[PositionAGLS]]
+|r1= [[Array]] format [[PositionAGLS]] where Z is the height over the surface underneath
 |s2= [[getPos]] location
@@ Line 42: / Line 46: @@
 |p21= location: [[Location]]
-|r2= [[Array]] - format [x,y,z], where z is {{hl|-1 * [[getTerrainHeightASL]]}} at the location
+|r2= [[Array]] format [x,y,z], where Z is {{ic|-1 * [[getTerrainHeightASL]]}} at the location
 |s3= origin [[getPos]] [distance, heading]
@@ Line 77: / Line 81: @@
 |x4= Find position 100 metres and 45 degrees from player position:<code>[[player]] [[getPos]] [100, 45];</code>
+|x5= Determine if a free-falling unit is close enough to the surface (including buildings, aircraft carriers etc) below to deploy the parachute:
+<code>[[waitUntil]] { [[sleep]] 1; [[getPos]] [[player]] [[select]] 2 [[a_less_b|<]] 200 };
+[[hint]] "Deploying a parachute might be a good idea";</code>
 |seealso= [[getPosVisual]], [[getRelPos]], [[setPos]], [[Position#setPosAGLS|setPosAGLS]], [[position]], [[getPosATL]], [[getPosASL]], [[getPosASLW]], [[visiblePosition]], [[visiblePositionASL]], [[getMarkerPos]]