Tile Utilities for Pixi.js

Tile Utilities is a collection of helpful methods and objects for using Tiled Editor with the Pixi renderering engine.

makeTiledWorld is the most important method, so read the documentation ahead to find out how it works, and then read about how you can use the other methods for supplementary features.

Yes, Tile Utilities also contains a full suite of tools for working with isometric maps! That means: isometric collision detection, mouse/touch pointer selection of isometric tiles, and importing of isometric maps created in Tiled Editor.

You can find working examples of how all these methods are used by the Hexi game engine in the links below (click the image links to play the examples and use the arrow keys to move the game characters):

Here's the source code.

Here's the source code.

These two examples are the best place to start learning about how to use the Tile Utilities methods and objects.

But Tile Utilities also works with isometric maps.

Here's the source code.

And, it has a shortestPath function that will tell you the shortest path between two index points on a map array.

Which can be used to help a game character navigate through a maze.

If you need to implement a scrolling camera to your game world, use the worldCamera method from the Game Utilities library.

If you have any questions about how any of these methods work, just ask in this repository's Issues.

Table of Contents

Installation Setting up makeTiledWorld: Create a Pixi game scene from a Tiled Editor JSON data file. getObject: Access an object from a Tiled Editor map as a Pixi sprite. Create sprites from map objects: Use a Tiled Editor object to make a Pixi sprite. Layer groups: Access a Tiled Editor layer group. GID values: Accessing and using Tiled Editor GID map array values. Using the data array: Accessing and using Tiled Editor data array values. getObject: Accessing multiple sprites in a Tiled Editor map. hitTestTile: An all-purpose collision method for tile-based games. getIndex: Convert a sprite's x and y position to a map index value. getTile: Convert a map index value into a sprite's x and y screen position. surroundingCells: Find all the map array index numbers surrounding a center index number. getPoints: Find all the map array index numbers surrounding a center index number. byDepth: And array sort function for isometric maps that depth-sorts sprites according to their z properties. hitTestIsoTile: Collision detection for isometric sprites. getIsoPoints: The isometric equivalent of getPoints. makeIsoPointer: Add isometric properties to a mouse/touch pointer so that you can select isometric tiles. isoRectangle: Creates an isometric rectangle that's useful for prototyping isometric maps. addIsoProperties: Adds isometric properties to any sprite to automatically convert between Cartesian and isometric coordinates. makeIsoTiledWorld: Creates an isometric world from a Tiled Editor JSON data file. The isometric verision of makeTiledWorld. shortestPath: An A-Star algorithm that finds the shortest path between two points in a map array. tileBasedLineOfSight: Find out whether two sprites are visible to each other inside a tile-based maze environment.

Installing Tile Utilities

NPM

npm install pixi-tile-utilities --save

CDN

<script src="https://unpkg.com/pixi-tile-utilities/dist/tile-utilities.min.js"></script>

Setting up

Link the tileUtilities.js file from this repository's bin folder to your HTML document with a <script> tag. (Or, load it into your JS file using any module system you prefer.) Next, instantiate TileUtilites in your JS file like this:

let tu = new TileUtilities(PIXI);

The constructor requires a reference to the PIXI object you have running in your application. If you don't supply one, tileUtilites.js will look for a global PIXI object. If it can't find Pixi for some reason, it will throw you an error to let you know.

You can now access all the TileUtilities methods with the tu object in your application.

makeTiledWorld

makeTiledWorld is a quick and easy way to display a game world designed in Tiled Editor. Supply makeTiledWorld with 2 string file path arguments:

1. A JSON file generated by Tiled Editor. Important: the Tile Layer Format has to be CSV format (Comma Seperated Value.)
2. A source image that represents the tileset you used to create the Tiled Editor world.

let world = tu.makeTiledWorld("tiledEditorMapData.json", "tileset.png");

(Note: makeTiledWorld looks for the JSON data file in Pixi's loader.resources object. So, make sure you've loaded the JSON file using Pixi's loader.)

makeTiledWorld will return a Pixi Container that contains all the things in your Tiled Editor map as Pixi sprites.

All the image tiles you create in Tiled Editor are automatically converted into Pixi sprites for you by makeTiledWorld. You can access all of them using two methods: getObject (for single sprites) and getObjects (with an "s") for multiple sprites. Let's find out how they work.

world.getObject

Tiled Editor lets you assign a "name" property to any object. You can access any sprite by this name using the getObject method. getObject searches for and returns a sprite in the world that has the same name property that you assigned in Tiled Editor. Here's how to use getObject to look for an object called "alien" in the Tiled map data and assign it to a variable called alien

let alien = world.getObject("alien");  

alien is now an ordinary Pixi sprite that you can control just like any other Pixi sprite in your games.

Creating sprites from generic objects

Tiled Editor lets you create generic objects. These are objects that don't have images associated with them. Generic objects are handy to use, because they let you create complex game objects inside Tiled Editor, as pure data. You can then use that data your game code to build complex game objects.

For example, imagine that you want to create a complex animated walking sprite called "elf". First, create the elf object in Tiled Editor as a generic object, but don't assign any image tiles to it. Next, in your game code, create a new Pixi AnimatedSprite called elf and give it any textures you want to use for its animation states.

let elf = new PIXI.extras.AnimatedSprite(elfSpriteTextures);

Then use the x and y data from the generic "elf" object you created in Tiled Editor to position the elf sprite.

elf.x = world.getObject("elf").x;
elf.y = world.getObject("elf").y;

This is a simple example, but you could make very complex data objects in Tiled Editor and use them to build complex sprites in the same way.

Accessing Tiled Editor layer groups

Tiled Editor lets you create layer groups. Each layer group you create in Tiled Editor is automatically converted by makeTiledWorld into a Pixi Container object. You can access those containers using getObject to extract the layer group container.

Here's how you could extract the layer group called "objects" and add the elf sprite to it.

let objectsLayer = world.getObject("objects");
objectsLayer.addChild(elf);

If you want to add the sprite to a different world layer, you can do it like this:

world.getObject("treeTops").addChild(elf);

If you want to access all the sprites in a specific Tiled Editor layer, just supply getObject with the name of the layer. For example, if the layer name is "items", you can access it like this:

let itemsLayer = world.getObject("items");

itemsLayer is now a Pixi container with a children array that contains all the sprites on that layer.

To be safe, clone this array to create a new version that doesn't point to the original data file:

items = itemsLayer.children.slice(0);  

You can now manipulate the items array freely without worrying about changing the original array. This can possibly help prevent some weird bugs in a complex game.

Finding the "gid" values

Tiled Editor uses "gid" numbers to identify different kinds of things in the world. If you ever need to extract sprites with specific gid numbers in a layer that contains different kinds of things, you can do it like this:

let items = itemsLayer.children.map(sprite => {
  if (sprite.gid !== 0) return sprite; 
});

This example will give you a new array called items that contains sprites that don't have gid values of 0.

Every sprite created by makeTiledWorld has a gid property with a value that matches its Tiled Editor "gid" value.

Accessing a layer's "data" array

Tiled Editor's layers have a data property that is an array containing all the grid id numbers (gid) of the tiles in that array. Imagine that you've got a layer full of similar tiles representing the walls in a game. How do you access the array containing all the "gid" numbers of the wall sprites in that layer? If the layer's name is called "wallLayer", you can access the wallLayer's data array of sprites like this:

wallMapArray = world.getObject("wallLayer").data;

wallMapArray is now an array of "gid" numbers referring to all the sprites on that layer. You can now use this data for collision detection, or doing any other kind of world building.

world.getObjects

There's another method called getObjects (with an "s"!) that lets you extract an array of sprites from the Tiled Editor data. Imagine that you created three game objects in Tiled Editor called "marmot", "skull" and "heart". makeTiledWorld automatically turns them into sprites, and you can access all of them as an array of sprites using getObjects like this:

let gameItemsArray = world.getObjects("marmot", "skull", "heart");

hitTestTile

hitTestTile checks for a collision between a sprite and a tile in any map array that you specify. It returns a collision object. collision.hit is a Boolean that tells you if a sprite is colliding with the tile that you're checking. collision.index tells you the map array's index number of the colliding sprite. You can check for a collision with the tile against "every" corner point on the sprite, "some" corner points, or the sprite's "center" point.

tu.hitTestTile(sprite, array, collisionGid, world, pointsToCheck);

The world object (the 4th argument) has to have these properties: tileheight, tilewidth, widthInTiles. pointsToCheck can have the string value "some", "every" or "center".

Here's how you could use hitTestTile to check for a collision between a sprite called alien and an array of wall sprites with map gid numbers of 0.

let alienVsFloor = tu.hitTestTile(alien, wallMapArray, 0, world, "every");

alienVsFloor will be object with two properties: hit and index. You can use these values to resolve the collision.

For working example of hitTestTile, and how to resolve collisions, see this example from the Hexi game engine.

getIndex

The getIndex helper method converts a sprite's x and y position to an array index number.
It returns a single index value that tells you the map array index number that the sprite is in.

tu.getIndex(sprite.x, sprite.y, tileWidth, tileHeight, mapWidthInTiles);

getTile

The getTile helper method converts a tile's index number into x/y screen coordinates, and captures the tile's grid index (gid) number. It returns an object with x, y, centerX, centerY, width, height, halfWidth halffHeight and gid properties. (The gid number is the value that the tile has in the mapArray) This lets you use the returned object with 2D geometric collision functions like hitTestRectangle or rectangleCollision from the Bump collision library.

Supply getTile with a map array index number, the map array, and the world object that represents your game world.

tu.getTile(index, mapArray, world);

The world object requires these properties: x, y, tilewidth, tileheight and widthInTiles

surroundingCells

The surroundingCells helper method returns an array containing 9 index numbers of map array cells around any given index number. Use it for an efficient broadphase/narrowphase collision test. The 2 arguments are the index number that represents the center cell, and the width of the map array.

let cells = tu.surroundingCells(index, widthInTiles);

getPoints

The getPoints method takes a sprite and returns an object that tells you what all its corner points are. The return object has four properties, each of which is an object with x and y properties:

• topLeft: x and y properties describing the top left corner point.
• topRight: x and y properties describing the top right corner point.
• bottomLeft: x and y properties describing the bottom left corner point.
• bottomRight: x and y properties describing the bottom right corner point.

If the sprite has a collisionArea property that defines a smaller rectangular area inside the sprite, that collision area can be used for collisions instead of the sprite's dimensions. Here's how you could define a collsionArea on a sprite called elf:

elf.collisionArea = {x: 22, y: 44, width: 20, height: 20};

Here's how you could use the getPoints method to find all the collision area's corner points.

let cornerPoints = tu.getPoints(elf.collisionArea);

byDepth

If your sprites in an isometric map have z properties that define their depth layers, you can depth-sort them using the array byDepth method like this:

world.children.sort(tu.byDepth);

hitTestIsoTile

Same API as hitTestTile, except that it works with isometric sprites. Make sure that your world object has properties called cartTileWidth and cartTileHeight that define the Cartesian width and height of your tile cells, in pixels.

getIsoPoints

Get all the map index numbers surrounding an isometric map cell. The isometric equivalent to getPoints

makeIsoPointer

Used to add a isometric properties to any mouse/touch pointer object with x and y properties. Supply makeIsoPointer with the pointer object and the isometric world object. As long as your pointer object has x and y position values, it should work.

tu.makeIsoPointer(pointer, world);

It adds the following properties to the pointer object:

pointer.cartX    //The Cartesian x position on the isometric map
pointer.cartY    //The Cartesian y position on the isometric map
pointer.column   //The isometric column over which the pointer is touching
pointer.row      //The isometric row over which the pointer is touching
pointer.index    //The map array index value of the current isometric tile

isoRectangle

Creates an isometric rectangle (squashed diamond shape) that's useful for prototyping isometric maps. Its first two arguments are the Cartesian width and height of your map's tile cells, and the third is the color. For example:

sprite = tu.isoRectangle(world.cartTilewidth, world.cartTileheight, 0xCCCCFF);

addIsoProperties

Adds isometric properties to any sprite:

tu.addIsoProperties(anySprite);

The sprite now has these properties: cartX, cartY, isoX, isoY, cartWidth, cartHeight.

makeIsoTiledWorld

Creates an isometric world using Tiled Editor JSON map data.

Here's the source code.

makeIsoTiledWorld uses the same API as its Cartesian equivalent makeTiledWorld method. However, you need to make sure you set Tile Editor up correctly and add some custom map properties to make it work. Let's find out how.

###Configuring and building the map Before you start creating your Tiled Editor map, prepare a sprite sheet with the isometric tiles that you want to use. And, very importantly, note down the isometric dimensions of sprites. Here are the pixel dimensions you need to know: • tilewidth: The width of the sprite, from its left to right edge. • tileheight: The height of the tileheighte’s base area. This is just the height of the squashed diamond shape which defines the base on which the isometric sprite is standing. Usually its half the tilewidth value.

These properties are the property names that are used by Tiled Editor, and you’ll be able to access them in the JSON data file that Tiled Editor generates.

You can now use the values to create a new isometric map in Tiled Editor. Open Tiled Editor and select File ~TRA New from the main menu. In the New Map dialog box, select isometric as the Orientation, and use the tilewidth and tileheight values I described above for the Width and Height.

But we’re not done yet! There are three more values we need to figure out:

• tileDepth: The total height of the isometric sprite, in pixels. • cartWidth: The Cartesian width of each tile grid cell, in pixels. • cartHeight: The Cartesian height of each tile grid cell, in pixels.

You need to add these values as custom properties in Tiled Editor’s Map Properties panel.

When Tiled Editor generates the JSON map data, you'll be able to access these values in the properties field.

"properties":
    {
     "cartTileheight":"32",
     "cartTilewidth":"32",
     "tileDepth":"64"
    },

Now that you’ve got the Map Properties all set up, use your isometric tileset to build your world. Here's an example of what your Tiled Editor workspace might look like.

You can see in the image above that I’ve given the red cube a custom name property with the value “player”. I’ve also built the map using two layers: the playerLayer just contains the red cube, and the wallLayer contains all the maze walls. When you're finished designing your map, export it as a JSON file, and you’re now ready to use it to start coding a game. Here's how to use makeIsoTiledWorld from the JSON map data and isometric cubes.png tileset.

world = tu.makeIsoTiledWorld(
  "images/cubes.json",
  "images/cubes.png"
);

shortestPath

An A-Star search algorithm that returns an array of grid index numbers that represent the shortest path between two points on a map. Use it like this:

let shortestPath = tu.shortestPath(
  startIndex,               //The start map index
  destinationIndex,         //The destination index
  mapArray,                 //The map array
  mapWidthInTiles,          //Map wdith, in tiles
  [1,2],                    //Obstacle gid array
  "manhattan",              //Heuristic to use: "manhatten", "euclidean" or diagonal"
  true                      //Use diagonal routes (true) or orthogonally adjacent routes ()
);

tileBasedLineOfSight

Use the tileBasedLineOfSight function to find out whether two sprites are visible to each other inside a tile based maze environment.

let hasLineOfSight = tu.tileBasedLineOfSight(
  spriteOne,      //The first sprite, with `centerX` and `centerY` properties
  spriteTwo,      //The second sprite, with `centerX` and `centerY` properties
  mapArray,       //The tile map array
  world,          //The `world` object that contains the `tilewidth
                  //`tileheight` and `widthInTiles` properties
  emptyGid = 0,   //The Gid that represents and empty tile, usually `0`
  segment = 32,   //The distance between collision points
  angles = []     //An array of angles to which you want to 
                  //restrict the line of sight
);