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Spiderswine

Navigation System featuring Dijkstra-Algorithm

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Hey Folks,

 

recently i was playing a bit with setting up the dijkstra algorithm in arma.

With the following code you will be able to navigate from your position to a marker on the map.

 

Have Fun!

 

Video Tutorial:

 

Tutorial on YouTube

 

 

Parts of the Algorithm:

 

  • Create Road Map, Gets all connected roads on the map and save them in an array
  • Run the Dijkstra Algorithm, Defines the graph for the RoadMap with recent starting point

  • Finding the Path, Gets the position of the destination marker on the map and finds the shortest path
  • Create Local Markers, Create markers for every path node
  • Delete Markers on Passing, When passing the navigation markers they will be deleted from the gui

 

 

Create Road Map

// Create Road Map 

_roadMap = [];
_nextRoads = [];		
_finishedRoads = [];

_startRoads = player nearRoads 10;
_firstRoad = _startRoads select 0;
_nextRoads pushBack _firstRoad;
	
_iterationCounter = 0;

while {_iterationCounter < 1000} do
{	
	_nextRoad = _nextRoads deleteAt 0;	
	_connectedRoads = roadsConnectedTo _nextRoad;
	
	{
		_distance = _x distance _nextRoad;
		_roadMap pushBack [_nextRoad, _x, _distance];
		
		if((_finishedRoads find _x) == -1) then
		{
			_nextRoads pushBack _x;
		};
		
	} foreach _connectedRoads;
	
	_finishedRoads pushBack _nextRoad;	
	_iterationCounter = _iterationCounter +1;
};

 

Run the Dijkstra Algorithm

// Run the Dijkstra Algorithm
_startRoads = player nearRoads 10;
_startRoad = _startRoads select 0;

// Init Distances
_distanceArray = [];
_workQueue = [];

_distanceArray pushBack [_startRoad, 0, null];

_visitedRoads = [];
_visitedRoads pushBack _startRoad;
_workQueue pushBack [0, _startRoad];

while { count _workQueue > 0} do
{
	_workItem = _workQueue deleteAt 0;
	_actualRoad = _workItem select 1;

	// Get the connected Roads out the RoadMap
	{
		_road = _x select 0;
		_connRoad = _x select 1;
		_connDistance = _x select 2;
		
		if ((_road == _actualRoad) && !(_connRoad in _visitedRoads)) then	// Find Connected Roads, not yet visited
		{
			_visitedRoads pushBack _connRoad;					// Save connected road as visited
			
			// Calculate Distance between the Roads
			_roadDistance = _connDistance;
			
			// Search for Parent in Distance Array and get his Distance
			{
				_parentRoad = _x select 0;
				_parentDistance = _x select 1;
				_parentParent = _x select 2;
				
				if(_parentRoad == _road) then 
				{
					_roadDistance = _roadDistance + _parentDistance;		// Add distance of parent to new distance
				};
				
			} foreach _distanceArray;
			
			// Save new Road in Distance Array
			_distanceArray pushBack [_connRoad, _roadDistance, _road];	// Add connected road to Distance Array
			_workQueue pushBack [_roadDistance, _connRoad];				// Add connected road to queue
		};
	} forEach _roadMap;
	
	if(count _workQueue  > 0) then {_workQueue sort true;};
};

 

Finding the Path

// Now Finding the Shortest Path to Destination
_destinationPath = [];
_destinationLength = 0;

_startNode = _distanceArray select 0;

// Get the Destination Node from Marker
_destinationMarker = allMapMarkers select ((count allMapMarkers) -1);

_nearestDestinationRoad = (getMarkerPos(_destinationMarker) nearRoads 10) select 0;

_selectedNode = [];

// Find DestinationRoad in Array
{
	_nodeRoadx = _x select 0;
	
	if(_nodeRoadx == _nearestDestinationRoad) then
	{
		_selectedNode = _x;
	}
} foreach _distanceArray;

// Get the Distance to Destination
_destinationLength = _selectedNode select 1;

diag_log format ["StartNode: %1, SelectNode: %2, DestinationLength: %3", _startNode, _selectedNode, _destinationLength];

// Get the Path to Destination
while{!(_selectedNode isEqualTo _startNode)} do
{
	_nodeRoad = _selectedNode select 0;			// Select the Road in the Node
	_destinationPath pushBack _nodeRoad;		// Save the Road in the Path
	_nodeParent = _selectedNode select 2;		// Node Parent to find	
	
	// Find Node Parent in Distance Array
	{
		_nodeRoadx = _x select 0;
		
		if(_nodeRoadx == _nodeParent) then
		{
			_selectedNode = _x;
		}
	} foreach _distanceArray;
};

_destinationPath pushBack (_startNode select 0);

 

Create Local Markers

// Create Local Markers to navigate to the path
{
	_streetMarker = "VR_3DSelector_01_exit_F" createVehicleLocal getPos(_x);
	// _mapMarker = createMarkerLocal ["markername",[getPos(_x select 0) select 0,getPos(_x select 0) select 1]];
	// _mapMarker setMarkerShapeLocal "ICON";
	// _mapMarker setMarkerTypeLocal "DOT";
} foreach _destinationPath;

 

Delete Markers on Passing

// Delete Local Markers when passing them
[] spawn {
	while{true} do
	{
		_nearestObjects = nearestObjects [player, [], 10];
		{
			if(typeOf _x == "VR_3DSelector_01_exit_F") then
			{
				deleteVehicle _x;
			}		
		} foreach _nearestObjects;
		sleep 0.1;
	}
}

 

 

 

 

 

Edited by Spiderswine
Update for Full Function
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  • Thanks 1

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this might be useful to you: 

 

thanks for sharing the script!

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Thanks for posting, but my aim was to set up a navigation system for players on a server, luckely this works now a bit better ;)

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