TileNodeNetwork

Introduction

The TileNodeNetwork object is a type of NodeNetwork which is designed specifically for tile-based games. Since the TileNodeNetwork object inherits from NodeNetwork, all available methods in NodeNetwork are available in TileNodeNetwork. Therefore, you should check out the NodeNetwork page for additional information and features on the TileNodeNetwork object. Normally a TileNodeNetwork is used when creating a game which uses tile maps.

For information on creating a TileNodeNetwork in the FlatRedBall Editor (this isthe most common approach), see the FlatRedBall Editor TileNodeNetwork page.

Benefits of the TileNodeNetwork

The TileNodeNetwork offers the following benefits:

• Simple addition of tiles on a grid-based system using four or eight-way movement.

• Quick index based ( O(1) ) tile finding

• Concept of tile occupation to prevent multiple characters moving on the same tile.

Example - Creating a TileNodeNetwork In Code

The following code creates a TileNodeNetwork that is 10X10 with has a seed (bottom left tile) at 0,0. Add the following using statement:

using FlatRedBall.AI.Pathfinding;

Add the following to Initialize after initializing FlatRedBall:

float xSeed = 0;
float ySeed = 0;
float distanceBetweenNodes = 32;
int numberOfNodesX = 10;
int numberofNodesY = 10;

TileNodeNetwork tileNodeNetwork = new TileNodeNetwork(
    xSeed, 
    ySeed, 
    distanceBetweenNodes, 
    numberOfNodesX, 
    numberofNodesY, 
    DirectionalType.Four);

tileNodeNetwork.FillCompletely();

tileNodeNetwork.Visible = true;

Example - Creating a TileNodeNetwork from a TileMap in Code

The following code can be used to create a TileNodeNetwork using a loaded TMX file:

// Assuming WorldMap is a valid Tiled map

var tileNodeNetwork = new TileNodeNetwork(GridWidth / 2f,
    -WorldMap.Height + GridWidth / 2f,
    GridWidth,
    MathFunctions.RoundToInt(WorldMap.Width / WorldMap.WidthPerTile.Value),
    MathFunctions.RoundToInt(WorldMap.Height / WorldMap.HeightPerTile.Value)
    DirectionalType.Eight);

const string nameToLookFor = "PathTile";

foreach(var layer in WorldMap.MapLayers)
{
    var indexes = layer.NamedTileOrderedIndexes.ContainsKey(nameToLookFor) ? 
        layer.NamedTileOrderedIndexes[nameToLookFor] : null;

    if (indexes != null)
    {
        var count = indexes.Count;
        for (int i = count - 1; i > -1; i--)
        {
            float tileLeftX, tileBottomY;
            layer.GetBottomLeftWorldCoordinateForOrderedTile(indexes[i], out tileLeftX, out tileBottomY);
        
            // If we use the bottom-left position for adding a node network, floating point error may cause
            // the node to be positioned in one of four tiles that touch the corner. Shift the position up and
            // to the right to avoid this by GridWidth/2
            tileNodeNetwork.AddAndLinkTiledNodeWorld(tileLeftX + GridWidth/2.0f, tileBottomY + GridWidth/2.0f);
        }
    }
}

Note that the example above uses a name (PathTile) for simplicity, but you can also use properties. You simply have to convert the properties to a list of names:

...
var tileNamesForPath = WorldMap.TileProperties
                .Where(item => item.Value
                .Any(customProperty => customProperty.Name == "IsPath" && (string)customProperty.Value == "true"))
                .Select(item => item.Key)
                .ToArray();



foreach(var layer in WorldMap.MapLayers)
{
    foreach(var nameToLookFor in tileNamesForPath)
    {
        var indexes = layer.NamedTileOrderedIndexes.ContainsKey(nameToLookFor) ? 
            layer.NamedTileOrderedIndexes[nameToLookFor] : null;

        if (indexes != null)
        {
            ...
        }
    }
}