create relative positions (for spawning)

[slimSpencer 10]

Hello gentlemen,

for a mission i'm currently working on, i want to spawn custom arrays of different units. However, the problem i had with BIS_fnc_spawnGroup was, that all units (especially bigger ones, like tanks) were spawned exactly at given position so they collided & flew thru the air...

So i wrote a function to create relative positions for a given array of unit-types, considering their approx. size. It also returns, if you whish, the necessary free space (as radius around center) needed to safely place all given unit-types using their relative positions. (Use it with findEmptyPosition, e.g.)

I found it quite useful so i decided to share it with you...

(Yes, i know, there are dozens of other & maybe more elegant ways to get around this - but i just wanted to write exactly this fnc as it suits my current needs at best. And, as you know, every single sqf increases your scripting-skills a little bit further ;))

...How it basically works:

Creates a circle around center ([0, 0]) and tries to "place" actual unit there in fixed degree-steps (starting from North), considerung minimun distance to every other already created unit-position.

If not successful, circle-radius will be increased in a slightly exponential way and search starts again from North. If successful, circle-radius will be reset and next unit-position will be searched...

(Feel free to adjust search-params in fnc to your needs...)

...Parameters:

_this select 0 (array) - array with unit/vehicle-types as string, e.g. ["USMC_Soldier", "USMC_Soldier", "M1A1", ...]

_this select 1 (bool) - (optional) if true, necessary minimum space for creating all given units will also be returned

_this select 2 (position) - (optional) if given, output of this function will be drawn at given position

...Returns:

array with one or two elements:

(1) - nested array with relative unit positons (2D)

(2 - optional) - total free space needed to create the whole group (number - radius from center)

spf_createRelPos.sqf

/*
spf_createRelPos.sqf

created by slimSpencer / v0.1
-
creates, for given unitTypes, relative positios (2D) around center (0, 0) (for use with BIS_fnc_spawnGroup, e.g.).
Size of each given unit will be considered in a simplified way (using parent-class). 

Creates a circle around center and tries to "place" actual unit there in fixed degree-steps (starting from North),
considerung minimun distance to every other already created unit-position. If not successful, circle-radius will be increased
in a slightly exponential way and search starts again from North.
If successful, circle-radius will be reset and next unit-position will be searched.

Please feel free to tweak search-parameters to your needs.
-
Returns an array with one or two elements:
(1) nested array with relative unit positons (2D)
(2 - optional) total free space needed to create the whole group (number - radius from center).
(use it, e.g., with findEmptyPosition beforce calling your spawn-script.)
-
Parameters:
_this select 0 (array) - array with unit/vehicle-types as string, e.g. ["USMC_Soldier", "USMC_Soldier", "M1A1", ...]
_this select 1 (bool) - (optional) if true, necessary minimum space for creating all given units will also be returned
_this select 2 (position) - (optional) if given, output of this function will be drawn at given position

todo: param-validation

*/

spf_createRelPos = {

//search-params
_dirStep = 20; // (20 = 18 steps per circle (360 / 20)
_radAroundCenterIncMul = 1.35; //multiplier to increase circle after every non-successful pass - if too small, we will have MANY iterations
_radAroundCenterStart = 3; //radius of first circle

//init vars...
_retFreeSpace = false;
_greatestDistCenter = 0;
_drawOutput = false;
_drawCenter = [];
_circles = [];
_radAroundCenter = 0;

_testPos = [];	
_center = [0, 0];
_posCol = []; //position-collector [x, y, <minDist from actual point to all other points>, direction]	
_return = [];	

//read function-params
_unitArr = _this select 0;

if ((count _this) > 1) then	{
	_retFreeSpace = _this select 1;		
};

if ((count _this) > 2) then	{
	_drawOutput = true;
	_drawCenter = _this select 2;
	_circles = [];
};

//go thru all units...
{			
	//get minimum distance to other units for actual unit
	_class = getText(configFile >> "CfgVehicles" >> _x >> "simulation");
	//better: use true 3d-model-size... but don't know any method to read before model is spawned on map

	_dist = 2.5; //ok for men - for veh, we need larger dist...
	switch (_class) do
	{
		case "tank": {_dist = 12;};
		case "car": {_dist = 7;};			
		case "airplane": {_dist = 50;};
		case "helicopter": {_dist = 50;};
		case "ship": {_dist = 20;};
	};

	//reset radius & _posFound
	_radAroundCenter = _radAroundCenterStart;
	_posFound = false;

	//main search-loop for actual unit
	while {!_posFound} do {	

		//reset dir
		_dir = 0;			

		//circle-loop
		while {(!_posFound) and (_dir <= 360)} do {

			//if _drawOutput=true, collect actual circle for later marker creation
			if (_drawOutput) then {
				if (!(_radAroundCenter in _circles)) then {_circles = _circles + [_radAroundCenter];};
			};	

			//test _testPos against all created positions by now
			_testPos = [_center, _radAroundCenter, _dir] call BIS_fnc_relPos;				

			if (count _posCol == 0) then
			{
				//pos for first unit is allways ok
				_posFound = true;	
			}
			else
			{				 
				//set true first and then, if nothing found, break out & set back to false
				_posFound = true;					
				{					
					//step to next direction for given circle if no valid pos found
					_xCoord = [_x select 0, _x select 1];
					_xDist = _x select 2;
					if ((_xCoord distance _testPos) < ((_xDist / 2) + (_dist / 2)))	exitWith {
						//set _posFound back to false if no valid pos found
						_posFound = false;	
						_dir = _dir + _dirStep				
					};						
				} forEach _posCol;																
			};				
		};

		if (_posFound) then
		{
			_posCol = _posCol + [[_testPos select 0, _testPos select 1, _dist, _dir]];
		}
		else
		{				
			//increase circle-radius if no valid pos found on actual circle
			_radAroundCenter = _radAroundCenter * _radAroundCenterIncMul;
		};		
	};		
} forEach _unitArr;


//write rel. pos. in _return
_tmpArr = [];
{
	_tmpArr = _tmpArr + [[_x select 0, _x select 1]];
} forEach _posCol;
_return = _return + [_tmpArr];

//if necessary free space should be returned, calc. & add it to _return
if (_retFreeSpace) then {

	_greatestDistCenter = 0;
	{
		_oldPos = [_x select 0, _x select 1];
		_dist = (_x select 2) / 2;
		_dir = _x select 3;
		_testPos = [_oldPos, _dist, _dir] call BIS_fnc_relPos;

		_distCenter = (_testPos distance _center);
		if (_distCenter > _greatestDistCenter) then {_greatestDistCenter = _distCenter};		
	} forEach _posCol;
	_return = _return + [_greatestDistCenter];
};

//if test-draw-position was given, create markers...
if (_drawOutput) then {

	//circles...
	{
		_tmp = createMarker [str((random 1) + (random 1)), _drawCenter];
		_rad = _x;
		_tmp setMarkerSize [_rad, _rad];
		_tmp setMarkerShape "ELLIPSE";
		_tmp setMarkerBrush "Border";
		_tmp setMarkerColor "ColorBlue";			
	} forEach _circles;	

	//unit-positions		
	{
		_newPos = [(_drawCenter select 0) + (_x select 0), (_drawCenter select 1) + (_x select 1)];
		_tmp = createMarker [str((random 1) + (random 1)), _newPos];
		_rad = (_x select 2) / 2;
		_tmp setMarkerSize [_rad, _rad];
		_tmp setMarkerShape "ELLIPSE";
		_tmp setMarkerBrush "Border";
		_tmp setMarkerColor "ColorRed";	

		_tmp = createMarker [str((random 1) + (random 1)), _newPos];
		_rad = 0.5;
		_tmp setMarkerSize [_rad, _rad];
		_tmp setMarkerShape "ELLIPSE";
		_tmp setMarkerBrush "Solid";
		_tmp setMarkerColor "ColorRed";				
	} forEach _posCol;

	//if calc. -> nec. free-space-area
	if (_retFreeSpace) then {
		_tmp = createMarker [str((random 1) * (random 1)), _drawCenter];
		_rad = _greatestDistCenter;
		_tmp setMarkerSize [_rad, _rad];
		_tmp setMarkerShape "ELLIPSE";
		_tmp setMarkerBrush "Border";
		_tmp setMarkerColor "ColorGreen";			
	};		
};

_return
};

...how results look like:

(as stated above under parameters, you can draw the output on map for testing reasons when you give a position with third parameter)

red: "units" and their estimated size

blue: used circles to search for valid unit positions

green: necessary total free-space

used parameters:

[_testUnits, true, _drawPos] call spf_createRelPos;
======================================
_drawPos is any pos on map where you want to draw output
_testUnits was this:
[
"skoda",
"M1A1",
"M1A1",
"USMC_Soldier",
"USMC_Soldier",
"USMC_Soldier",			
"M1A1",
"M1A1",
"M1A1",
"USMC_Soldier",
"USMC_Soldier",
"MTVR",
"USMC_Soldier",
"USMC_Soldier",
"USMC_Soldier",
"M1A1"			
];

I hope you enjoy it - any comments/suggestions/error-reports are really appreceated.

br

Spencer

Edited March 1, 2012 by slimSpencer

[kylania 567]

Really nice, thanks for sharing!

[twirly 11]

Agreed....thanks for sharing.