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html 5 2d + 2.5d (isometric) game engine

branch: master
README.md

Traffic Cone is a 2d and 2.5d (isometric) tile based game engine written for html5. It makes complex animations of sprites and tiles based worlds fairly simple.

Traffic Cone is currently client side only, so for multiplayer games you'll have to provide your own server. But expect to see more on this front soon, we're actively working on Traffic Cone server.

Features:

  • Easily configurable sprite animations
  • Simple to set up tile based worlds
  • Mock-3D math for layering, depth and positioning is handled for you via Traffic Cone's world models.
  • Basic Isometric pathfinding, AI and collision detection
  • Custom draw routines on sprites supported.
  • Granular control of sprite sequencing supported for more dramatic animations
  • Intelligent draw logic only draws modified parts of your canvas for better frame rates.

Examples:

Running the samples

This document is still a bit immature, but Traffic Cone comes with a set of sample that should help to illustrate some of the concepts below. They're webserver agnostic, but most of our testing has been with Nodejs using the Express framework. To run the sample, you essentially want to modify public/tccore/NotConstants.js (because they're not) and change your DOMAIN_PREFIX value to your webserver of choice and place everything under public so that it is available via that path. If you have nodejs installed and want to get up and running quickly you can modify DOMAIN_PREFIX to http://localhost:8089/ and then install expressjs and then run node webserver.js from the root trafficcone directory. From there all examples will be available via http://localhost:8089/examples/FILENAMEHERE.html

Create a simple 2D world with 2D sprites

The supporting example for this section can be found in public/examples/2D/2D.html. This example rips some art assets from Street Fighter 3 and shows you how to wire them together easily with some basic collision detection.

First and foremost, Traffic Cone requires two html 5 canvases to work with. To create a basic engine, you simply create a new instance of the Engine class and supply the canvas elements ala:

    ga = new Engine(document.getElementById("gamescreen"), document.getElementById("backbuffer2"));

The canvas is where all of our animations will be drawn. Animations come in the form of Sprites. Sprites are essentially animations which each image in the animation is made of Frames. Depending on how uniform your resources are, there are a few different ways to create a sprite. The assumption behind a sprite is that you are using a sprite sheet, and hence have an image of an animation sequence of some kind. For example see: https://github.com/j03m/trafficcone/blob/master/public/assets/ryu/RYU_PUNCH1.png

When we define a sprite, we essentially supply the definitions for this animation. Here is the mechanism that gives you the most control, whereby we define each frame of the movement.

//create a sprite
var ryu = new Sprite("ryu");
var ryu.setup(ga);

//tell traffic cone what the dimensions
var attack = [];
attack.push(new Frame(0, 0, 105, 127, fastAction));
attack.push(new Frame(0, 1, 105, 127, fastAction));
attack.push(new Frame(0, 2, 105, 127, fastAction));
attack.push(new Frame(1, 0, 105, 127, fastAction));
attack.push(new Frame(1, 1, 105, 127, fastAction));
attack.push(new Frame(1, 2, 105, 127, fastAction));
attack.push(new Frame(2, 0, 105, 127, fastAction));
attack.push(new Frame(2, 1, 105, 127, fastAction));

ryu.defineSequence("attack", "../../assets/ryu/RYU_PUNCH1.png", attack, 1);

Of course, that's fine if our sprite sheet isn't uniform is terms of spacing and positioning of each frame. If it is, we don't need to be so granular:

    ryu.easyDefineSequence("fall", "../../assets/ryu/RYU_FALL.png", 5, 5, 120, 178, fastAction, 1);

Here after the name and image, we simply supply the number of rows and columns. Then the height and width of each frame, the speed at which each frame should be played and the number of times it should played. While we can't control the speed of each frame granularly, we have also had to write much less code.

To tell our game engine about a sprite, we make it aware with:

ga.defineSprite(ryu);

We can also define a special sort of sprite to be one solid background image. Now this sort of thing won't be applicable to our isometric games usually (see below for more details) but for games with a solid unmoving background this works:

var bdImage = [];
bdImage.push(new Frame(0, 0, 512, 860, 0));
backDrop.defineSequence("backdrop", "../../assets/londonsubway/londonSubway.png", bdImage, playInfinite);
ga.setBackDrop(backDrop);

What I did here is I create a sprite with 1 frame and then told the game engine to use it as a backdrop.

Creating an isometric game world with mock-3D sprites

The supporting code for this section can be found public/examples/Isometric.html

Creating an isometric world is similar to 2D. But, now instead of just throwing sprites onto a canvas, we're going to define a GameWorld, which in turn will give us access to a GameWorldModel which we can use to place sprites in various aspects of "world space" and have that translate seamlessly to "canvas space". To create an isometric game world:

ga = new Engine(document.getElementById("gamescreen"), document.getElementById("backbuffer2"));
var gameWorld = new GameWorld(250, 250, 73, 73, GAME_WORLD_STYLE_ISOMETRIC);

After this you can populate the cells of your game world with various sprites. You can also tell the gameWorld what sort of rendering style these sprites have and if they are open. For example GAME_WORLD_CELL_UNDERLAY means the cell is always rendered under character aka "the floor" whereas GAME_WORLD_CELL_OVERLAY means the cell will appear over characters like a pillar or ceiling. In addition, cells can be available for characters to move into aka GAME_WORLD_CELL_OPEN vs closed off via GAME_WORLD_CELL_BLOCK. Let's look at the code from Helpers.js where we have a function MakeIsoMetricWorld().

First, let's make the sprites we need. We use one sprite sheet to represent all of the floor "tiles". See Cells.js for details. Then, we create a sprite that will look like a column.

worldCells = altarCells_Sprite(ga);
worldCells.setup(ga);
column = columnCell_Sprite(ga, "column");

Let's loop through the world and set each tile to a random floor tile from our sprite sheet:

for (var i = 0; i < worldSize; i++) {
    for (var ii = 0; ii < worldSize; ii++) {
        //set a cell using the worldCells sprite, randomly select one of the 25 frames in this sprite.
        gameWorld.Cells[i][ii] = new Cell(worldCells, getRand(5), GAME_WORLD_CELL_UNDERLAY, GAME_WORLD_CELL_OPEN, i, ii); 
    }
}

Nice, but a completely open world with no obstacles is hardly any fun. Let's add some columns to random cells:

for (var i = 0; i < columns; i++) {
    var xx = getRand(worldSize);
    var yy = getRand(worldSize);
    gameWorld.Cells[xx][yy] = new Cell(columnCell_Sprite(ga, "column" + i),0, GAME_WORLD_CELL_OVERLAY, GAME_WORLD_CELL_BLOCK, xx, yy);
}

Last, we need to tell our Engine about the gameworld so it knows what to render, and where to set the camera.

ga.setWorld(gameWorld);
ga.setCamera(worldSize/2, worldSize/2);

Once we have a world set up we can add some isometric sprites to the mix. For example from many of our examples we use our demo zombie isometric sprite:

var zom = zombie_Sprite(ga, "zombie1");

This zombie function wraps a call to our SpriteInventory class which is an abstraction around some of the sprite creation methods we reviewed earlier. It is important because it demonstrates how an isometric sprite differs from a 2d sprite. For an isometric sprite, we don't just "flip" a sprite when it changes direction as we saw in our 2d demo. In the 2D demo, each sprite had a series of animation representing a given state. When we wanted to change the sprites direction, we simply inverted the sprite.

However, for our isometric demos, each direction a sprite supports can have it's own animation. So, in this case create a hierarchy of sorts:

State - a set of animations representings the state of the sprite, ie the action the sprite is currently taking.
    Direction - an animation for a given state, in a given direction
        Frame - a frame of a given direction animation.

We accomplish this by supplying additional parameters to the defineSequence function:

 sprite.defineSequence(name, imagePath + imageName, sequence, state, undefined, undefined, direction);

Where the "direction" parameter indicates that a given sequence should be attached to a given direction. Directions are specified via:

var SPRITE_DIRECTION_UNDEFINED = "0";
var SPRITE_DIRECTION_NORTH = "-1";
var SPRITE_DIRECTION_NORTH_EAST = "-2";
var SPRITE_DIRECTION_EAST = "-3";
var SPRITE_DIRECTION_SOUTH_EAST = "-4";
var SPRITE_DIRECTION_SOUTH = "-5";
var SPRITE_DIRECTION_SOUTH_WEST = "-6";
var SPRITE_DIRECTION_WEST = "-7";
var SPRITE_DIRECTION_NORTH_WEST = "-8";

All 2D animations internally leverage SPRITE_DIRECTION_UNDEFINED by default. Most of the complexity outlined here can be avoided by creating a json sprite definition and then invoking the global TCSpriteFactory method as demonstrated in our sample zombie sprite file public/assets/zombie/zombie.js. Here we can see:

function zombie_Sprite(ga, name, loadCallBack) {
    var template = SpriteInventory.TCSpriteInventory["de558a04-b5df-4af4-b196-4393d732bb84"];
    var zombie = SpriteInventory.TCSpriteFactory(template, name, ga, loadCallBack);           
    return zombie;
}

Here we can see grab a template def from SpriteInventory.TCSpriteInventory using a guid and then pass that template to SpriteInventory.TCSpriteFactory generating our zombie sprite. Previous to this call we set up a json definition which defines the sprite:

//zombie
TCSpriteInventory["de558a04-b5df-4af4-b196-4393d732bb84"] = {
    usage: USAGE_NPC,
    prefix: "zombie",
    speed: 3, //todo: Sprites should have attributes like strength, speed, weight etc
    imagePath: DOMAIN_PREFIX + "assets/zombie/",
    audioPath: DOMAIN_PREFIX + "assets/zombie/",
    behavior:
    {
        seek: "hero",
        foundState: "attacking",
        moveState: "walking",
        leftGap: 10,
        topGap: 10,
        moveInterval: 100,
        definition: DOMAIN_PREFIX + "tccore/behaviors/SpriteSeeker.js",
        constructor: "SpriteSeeker(behavior.moveState, behavior.foundState)",
        eventType: "NPC",
        startState: "normal"
    },
    states:
    {
        normal:
        {
            name: "normal",
            columnRange: { start: 0, end: 3 },
            playState: -1,
            sound: "neutral1.mp3",
            speed: 200
        },
        walking:
        {
            name: "walking",
            columnRange: { start: 4, end: 11 },
            playState: -1,
            sound: "neutral6.mp3",
            speed: 200
        },
        attacking:
        {
            name: "attacking",
            columnRange: { start: 12, end: 21 },
            playState: 1,
            sound: "attack6.mp3",
            speed: 100
        },
        hit:
        {
            name: "hit",
            columnRange: { start: 21, end: 24 },
            playState: 1,
            sound: "gethit1.mp3",
            speed: 300
        },
        headsplode:
        {
            name: "headsplode",
            sound: "death2.mp3",
            columnRange: { start: 30, end: 37 },
            playState: 1,
            speed: 300
        },
        dead:
        {
            name: "dead",
            sound: "death2.mp3",
            columnRange: { start: 24, end: 29 },
            playState: 1,
            speed: 300
        }
    },
    neutralState: "normal",
    rowDirectionMap:
    [
        { row: 0, direction: SPRITE_DIRECTION_WEST, imageName: "zombie_0-0-0.png" },
        { row: 0, direction: SPRITE_DIRECTION_NORTH_WEST, imageName: "zombie_0-0-1.png" },
        { row: 0, direction: SPRITE_DIRECTION_NORTH, imageName: "zombie_0-0-2.png" },
        { row: 0, direction: SPRITE_DIRECTION_NORTH_EAST, imageName: "zombie_0-0-3.png" },
        { row: 0, direction: SPRITE_DIRECTION_EAST, imageName: "zombie_0-0-4.png" },
        { row: 0, direction: SPRITE_DIRECTION_SOUTH_EAST, imageName: "zombie_0-0-5.png" },
        { row: 0, direction: SPRITE_DIRECTION_SOUTH, imageName: "zombie_0-0-6.png" },
        { row: 0, direction: SPRITE_DIRECTION_SOUTH_WEST, imageName: "zombie_0-0-7.png" }
    ],

    tileHeight: 130,
    tileWidth: 128,
    drawWidth: 40,
    drawHeight: 60,
    initialDirection: SPRITE_DIRECTION_SOUTH_WEST
};

The idea behind this is that the json blobs would be stored on the server and requested as necessary via an ajax or jsonp loader, but that isn't quite ready yet and will be part of Traffic Cone server.

Inspecting and manipulating the isometric game world

Once you have sprites you'll obviously want to place them in the game world. You'll also want to know where they on screen and what cells are currently visible to the user's canvas (the view port). Ie, there's a whole big world that we have in memory, but we're only rendering what the user can see at any point in time. To handle this complexity for you, Traffic Cone provides an isometric game world model that can be fetched via:

    var gameWorldModel = ga.getWorldModel();

The game world model then lets you do simple things like place sprites in world/screen space without having to think of all the funky angles that come with tilting a grid into fake 3d (2.5d?) space. For example, here is some code that places one of our zombies in the cell at the very center of our world.

gameWorldModel.placeSpriteInCenterOfWorldCell((worldSize/2), worldSize/2, zom);

Creating a simple composite sprite

The supporting code for this example can be seen in: assets/hero.js

What is a composite sprite? A composite sprite is a sprite that instead of being made of a single sprite sheet is instead made of multiple images. While I'm sure there are lots of good reasons for doing this the main reason is usually allowing some sort of customizable or permutable characters. For example changing equipment and weapons etc. While this is great you should be cognizant that internally Traffic Cone treats each successive layer of a sprite as it's own canvas draw, so having a composite sprite that consists of 3 sets of images == 3 draws and has near the performance impact of three sprites. So be wary.

Traffic Cone supports two different types of composite sprites Simple and Complex. Simple composites which we'll discuss here are called simple because they expect that the artist has been diligent and "lined up" all of the different composite frames so that when layered on top of one another they are in the correct place. As such, simple composites are easy to configure, but it also means that all of the images have to be the same size as the largest of them. This isn't the end of the world, but it means your artists have to be very cognizant about size and positioning and you can't tweak offsets in code. So it's a bit limiting. If you don't mind, read on. If not, skip to complex composites.

If you're still reading, then let's take a look at some simple composite sheets. Our "hero" sprite asset is a simple composite, so let's start there. In his sprite definition from SpriteInventory.js we most of "hero" is pretty much like our Zombie isometric sprite. Not a lot of surprises.

//hero
TCSpriteInventory["9e4a24cf-c760-43ec-abda-3ef2db22e2ab"] = {
    usage: USAGE_PC,
    prefix: "hero",
    speed: 2,
    imagePath: DOMAIN_PREFIX + "assets/hero/",
    behavior:
    {
        foundState: "normal",
        moveState: "walking",
        moveInterval: 100,
        definition: DOMAIN_PREFIX + "tccore/behaviors/OriginSeeker.js",
        constructor: "OriginSeeker(behavior.moveState, behavior.foundState)",
        eventType: "mousedown",
        startState: "normal"
    },
    states:
    {
        normal:
        {
            name: "normal",
            columnRange: { start: 0, end: 0 },
            imageName: "male_base.png",
            playState: -1,
            speed: 200
        },
        walking:
        {
            name: "walking",
            columnRange: { start: 0, end: 4 },
            imageName: "male_base.png",
            playState: 1,
            speed: 200
        },
        attacking:
        {
            name: "attacking",
            columnRange: { start: 4, end: 6 },
            imageName: "male_base.png",
            playState: 1,
            speed: 100
        },
        bow:
        {
            name: "bow",
            columnRange: { start: 5, end: 5 },
            imageName: "male_base.png",
            playState: 1,
            speed: 100
        },
        hit:
        {
            name: "hit",
            columnRange: { start: 6, end: 6 },
            imageName: "male_base.png",
            playState: 1,
            speed: 100
        },
        dead:
        {
            name: "dead",
            columnRange: { start: 7, end: 7 },
            imageName: "male_base.png",
            playState: -1,
            speed: 300
        }
    },
    neutralState: "normal",
    rowDirectionMap:
    [
        { row: 0, direction: SPRITE_DIRECTION_WEST },
        { row: 1, direction: SPRITE_DIRECTION_NORTH_WEST },
        { row: 2, direction: SPRITE_DIRECTION_NORTH },
        { row: 3, direction: SPRITE_DIRECTION_NORTH_EAST },
        { row: 4, direction: SPRITE_DIRECTION_EAST },
        { row: 5, direction: SPRITE_DIRECTION_SOUTH_EAST },
        { row: 6, direction: SPRITE_DIRECTION_SOUTH },
        { row: 7, direction: SPRITE_DIRECTION_SOUTH_WEST }
    ],
    tileHeight: 260,
    tileWidth: 267,
    drawWidth: 125,
    drawHeight: 145,
    initialDirection: SPRITE_DIRECTION_SOUTH_WEST,
    chain: ["male_heavy.png", "male_longsword.png", "male_shield.png"]
};

However, there are some differences here. First off, let's look take a look at https://github.com/j03m/trafficcone/blob/master/public/assets/hero/male_base.png. For this image, he is pretty much just a nude base model. So obviously we need to layer some stuff on him to flesh him out. Note that last portion of the definition:

chain: ["male_heavy.png", "male_longsword.png", "male_shield.png"]

Here we added a series of images that will be "chained" on top of the sprite. If you look at https://github.com/j03m/trafficcone/blob/master/public/assets/hero/male_heavy.png you can see it animates his armor allowing us to change out his clothes. In addition, male_shield + male_longsword animate his weapons allowing those to be swapped in and out as well. However, look at how much negative space is in use in male_longswrod.

Under the hood, we're calling the sprite.chain method and sprite.unchain methods to add and remove images. Let's look at the implementation of TCSpriteFactory. On line 224 we can see that if the "chain" element of a sprite we end calling chain:

//handle image chains if the sprite has them defined.    
 var chain = spriteDef.chain;
 if (chain != undefined) //chaining is optional
 {
     for (var i = 0; i < chain.length; i++) {
         sprite.chain(imagePath + chain[i]);
     }
 }

In our latest sample - examples/simpleCompositeEqSwap.html we can see here that chain and unchain can be called by you on the fly to modify a sprites equipment on the fly. You'll see another weakness of simple composites here as well, there is no concept of order. So you'll see in order to layer the sprite correctly we have re-chain the shield whenever we change the base armor. Complex composites handle this for you with the trade off of having to write more code and be more diligent about our definitions.

Creating a complex composite sprite

Code supporting this section of the documentation can be seen in: examples/CompositeSprite.html

Creating a composite uses a function called SpriteInventory.createCompositeSprite. The details around this function can be seen in SpriteInventory.js. This method accepts a reference to the engine, a "composite definition" and a call back. The obvious meat is your composite definition.

So what the heck is in this composite definition? For complex composites, the composite definition is going to define everything from the different parts of a given sprite, the different animate states it will support etc. First and foremost let's review the hierarchy of stuff a complex composite sprite will support.

Prior to now, we have had the concept of a sprite, which can have many animations in many directions. Then in simple composite sprites we introduced the idea of "chained" animations so we could layer in different animations. Complex composites introduce the new concept of "parts". So for example, a sprite could have a chain of animations, but each of those animations is for a different part of the sprites body. For example, if I wanted to have a warrior character who could wear different pieces of armor on each part of his body, I could give the warrior a metal helmet, leather leggings, fingerless gloves and an chain-mail chest plate. I can support this type of thing with simple composites, but then my artists have to make sure every sprite sheet perfectly lines up. Composite sprites allow me to define each part of a given sprite and also supply independent offsets, padding rect overrides, frame lengths, widths, heights etc. As a result, you can create assets and then decouple the layout from the images and define some of that stuff in code. Complex composites also let's traffic cone find your resources on the fly so you have a common way of laying out your directory structures.

So, let's look at the composite def from the sample:

    var compositeDef = {
        characterClass: "AM",
        movementClass: "BOW",
        basePart: "TR",
        TR: "HVY",
        HD: "CAP",                
        LG: "HVY",
        RA: "HVY",
        LA: "HVY",
        RH: "PIK",
        LH: "LBB",          
        SH: "BUC",
        S1: undefined,
        name: "amazonGirl",
        states: states,
        actionDefs: hash,
        directionSortMap: directionSort,
        imageExtension: ".png"
    };

Here we are telling traffic cone that our character class is "AM" and that our movement class is "BOW". These are completely arbitrary tokens and can be whatever you want. I've used AM because my character class is "amazon warrior" and she will be using a "bow". These are essentially groupings of animations. If you want them to be "Mario" and "Default" to animate the default movements for your character "Mario", feel free to use those tokens. We'll talk about where tokens become important later.

After the class groupings comes the "parts" of a sprite. Each part can have a class of it's own. Parts are again, arbitrary tokens. So, here where you see "TR", "HD" etc, these are values I've used to represent my characters torso (TR) and head (HD). But they can be whatever you want. If you want to only have "body" and "shoes" for Mario, you can call them that. Next to each part token is it's "class" token. A part's class is essentially a variation of the "part" in question. So here, my character torso will be a heavy armor. So, I've specified TR:"HVY" where TR is my torso part token and HVY is my heavy armor class token. These are used to locate your sprite sheets for a given part (I'll explain that in a moment).

Each composite sprite still needs a base, but a base can be any part of the sprite. Later when we specify an offset for a given part/class/direction this offset will be relative to the base. You tell traffic cone which part is your base part using the "basePart:" attribute. In our example I tell traffic cone that TR (torso) is my base and all offsets are relative to it's rect. (We'll see how to define rects for individual parts in a moment).

In our example after basepart TR,HD,LG,RA,LA,RH,LH,SH,S1 are all parts token for my scheme. These are torso, head, legs, right arm, left arm, right hand, lef hand, shield, special 1. But - again, these are arbitrary, they can be whatever you want.

After these tokens, there are some required attributes. First is "name", which is just your sprite name. Next is the states attribute. STates is a definition of the animations your sprite will support. For example, running, jumping, hitting, singing etc. These are arbitrary values defined by you. In my code, my sprite will simple stand there looking cool, or walk. As such the object I supply for "states" is:

    var states = {
       "Neutral": "NU",
       "Walk": "WL"
    };

Next up is the more complex "actionDefs" or action definitions supply data needed to properly a given part. Actiondefs allows you to attach a definition to a given set of movement class, state, part, part class, direction. As such, you can override any animation. In addition, it supports a special token: "default" so that you can avoid having to specify each state if they have the same settings.

For example - looking at my amazon warrior sample, let's say I want to define an override for when my character's head, where she is wearing a mask, whenever she is walking east with a bow. I would supply something like this in the actionDefs object (note: we'll talk about the value of the object we supplied in a moment):

hash["BOWWLHDMSKEast"] = { offsetX: 20, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 };

What I did here is provide a string: [MovementClass][State][Part][Part Class][Direction]. As such whenever traffic cone is animating this particular sequence, it will utilize these settings. Now, let's say the value for the override we supplied is the same for all of my characters "Head" animations. Omg, do I really have to provide every possible permutation? No - to avoid this fate you can simply use the "default" token. In this case our definition would become:

hash["BOWWLHDdefault"] = { offsetX: 20, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 };

As a result any head animation in any direction will use the same settings. Let's say all of my characters bow walking animations should use the same settings. Omg, do I really have to provide all possible part combinations? No - again to do this all we have to do is move the default token up. So our def becomes:

hash["BOWWLdefault"] = { offsetX: 20, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 };

Okay, so that said, let's review the values you can supply as an actionDef. These are:

  • offsetX - OffsetX will adjust the destination draw x position of your source image relative to your basepart rect.
  • offsetY - OffsetY will adjust your destination draw y position of your source image relative to your basepart rect.
  • overRide - indicates that innerWidth + innerHeight should be obeyed.
  • innerWidth - indicates that your sprite sheet has padding in between frames and that your source width is really this value. It will adjust your source x coordinates in proportion to the difference between your frame width + innerWidth
  • innerHeight - Same as innerWidth, but for height.
  • frames - The number of frames in the animation
  • rows - The number of rows in your sprite sheet. Horizontal sheets supply 0 for rows.
  • cols - The number of columns in your sprite sheet. Vertical sheets should supply 0 for cols.
  • frameWidth - the width each frame in your sprite sheet
  • frameHeight - the height of each frame in your sprite sheet

So in our above example, we are supplying our amazon, walking with a bow default with { offsetX: 20, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 }.

You can see this in action in our CompositeSprite.html sample where we define a number of states for amazon girl the amazon warrior:

    var hash = {};
    //neutral defs
    hash["BOWNUHDBHMdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:30, frameHeight:64 };
    hash["BOWNUHDCAPdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };
    hash["BOWNUHDCRNdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:20, frameHeight:66 };
    hash["BOWNUHDFHLdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:20, frameHeight:64 };
    hash["BOWNUHDGHMdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:26, frameHeight:78 };
    hash["BOWNUHDHLMdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:20, frameHeight:62 };
    hash["BOWNUHDLITdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:28, frameHeight:67 };
    hash["BOWNUHDMSKdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 };
    hash["BOWNUHDMSKSouth"] = { offsetX: 20, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:33, frameHeight:65 };
    hash["BOWNUHDSKPdefault"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:20, frameHeight:63 };
    hash["BOWNULAHVYdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };
    hash["BOWNULALITEast"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:48, frameHeight:53 };
    hash["BOWNULAMEDEast"] = { offsetX: 30, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:48, frameHeight:52 };
    hash["BOWNUdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };

    //walking defs
    hash["BOWWLHDBHMdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:28, frameHeight:65 };
    hash["BOWWLHDCAPdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };
    hash["BOWWLHDCRNdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:22, frameHeight:67 };
    hash["BOWWLHDFHLdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:22, frameHeight:65 };
    hash["BOWWLHDGHMdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:24, frameHeight:79 };
    hash["BOWWLHDHLMdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:22, frameHeight:63 };
    hash["BOWWLHDLITdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:28, frameHeight:68 };
    hash["BOWWLHDMSKdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:32, frameHeight:66 };
    hash["BOWWLHDSKPdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:22, frameHeight:64 };
    hash["BOWWLLAHVYdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };
    hash["BOWWLLALITdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:45, frameHeight:54 };
    hash["BOWWLLAMEDdefault"] = { offsetX: 22, offsetY: 25, overRide: false, frames:7, cols:7, frameWidth:45, frameHeight:53 };
    hash["BOWWLLGHVYdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };
    hash["BOWWLdefault"] = { overRide: true, innerWidth: 80 , innerHeight: 100, frames:7, cols:7, frameWidth:252, frameHeight:203 };

(Now, mind you, most of these are screwy, amazon girls head tends to float away in certain directions for certain parts, but that is simply because my offsets are off, I'll correct it soon. The underlying mechanics of the engine however are working as expected.)

OKay, so last is the directionSortMap. As covered in simple composites, sometimes in order for the parts to look correct you have to draw them in a certain order. For example if our sprite is facing west, I have to draw her left arm after her torso or it will look like her torso is sitting on top of her arm. Ie, we need to tell traffic cone how parts should be arranged to support the correct perception of depth. We do this supplying traffic cone with an array of parts within an array of direction values. In addition, we can support a "default" order using the SPRITE_DIRECTION_UNDEFINED constant (which, isn't actually a constant, you can override these values if you want). For example:

    var directionSort = {};
    directionSort[SPRITE_DIRECTION_NORTH] = ["LH", "base", "HD", "LG", "RA", "LA", "RH"];
    directionSort[SPRITE_DIRECTION_NORTH_EAST] = ["LH", "base", "HD", "LG", "RA", "LA", "RH"];
    directionSort[SPRITE_DIRECTION_NORTH_WEST] = ["LH", "base", "HD", "LG", "RA", "LA", "RH"];
    directionSort[SPRITE_DIRECTION_UNDEFINED] = ["base", "LH", "HD", "LG", "RA", "LA", "RH"];

Here, we tell traffic cone that north, north east and north west should draw the left hand, the base part (torso), the head, the legs, the right arm, the left arm and then the right hand in that order and every other direction should draw the base part (torso), the left hand, the head, the legs, the right arm, the left arm, the right hand.

After that supply the definition to traffic cone via createCompositeSprite and it will create your sprite and notify you with the callback parameter. Once you've created the sprite you can pass a reference to the sprite and a modified composite definition to the SpriteInventory.setupCompositeSprite method to augment it. For example, in our sample we have provided some drop downs so you can swap out amazon girl's equipment. Each time a dropdown changes we call this swap function:

    function swap(part, value)
    {
        compositeDef[part] = value;
        SpriteInventory.setupCompositeSprite(hero, compositeDef);

    }

Here we take the part and the value we want to change and modify our composite definition. Then we pass it along with the sprite we want to change into setupCompositeSprite and thus amazon girl changes equipment.

Okay, but Joe - how do I get my images to traffic cone? Your code doesn't supply any images! This is because complex sprites automatically build a path to your images and grab them for you using the tokens you provided. Let's take the amazon girl sample again.

When creating the sprite, traffic cone will cobble together the path to your images using the following: [Class]/[Movement Class]/[State]/[Part]/[Part Class]/Direction.[imageExtension].

This highlights the last portion of the composite definition "imageExtention" which drops a .png or .jpg on the end of your images.

For example this means that our amazon girl head mask animation for her neutral state, facing east would be found at http://localhost:8089/AM/BOW/NU/HD/MSK/East.png where local host is the value set for DOMAIN_PREFIX in NotConstants.js.

While this methodology mandates the directory structure for your images, it will help you keep them organized and allow you to again decouple design from development. Ie, designers can continue creating content and dropping them onto your servers and developers only need to think about the token syntax in their scripts.

NPC Events and Controlling Input

The supporting code for this section can be found in pretty much all the samples, but for we'll specifically reference: examples/2D and examples/Isometric.html.

In order to set up input handlers for your characters as well as an "NPC Pulse" type of event, you will use the "addEventBehavior" method of our Engine class. The best place to see this sort of thing in action is in 2D/GameLogic.js. Here we can see the following code:

ga.addEventBehavior(ga.gameEvents.Idle, "", ryu, "ryu", null, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyDown, RIGHTARROW, ryu, "walkForward", moveRight, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyDown, LEFTARROW, ryu, "walkBack", moveLeft, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyUp, RIGHTARROW, ryu, "ryu", null, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyUp, LEFTARROW, ryu, "ryu", null, playInfinite);

   ga.addEventBehavior(ga.gameEvents.TouchStart, "", ryu, "walkForward", handleTouch, playInfinite);
   ga.addEventBehavior(ga.gameEvents.TouchEnd, "", ryu, "ryu", null, playInfinite);
   ga.addEventBehavior(ga.gameEvents.TouchMove, "", ryu, "walkForward", handleTouch, 1);

   ga.addEventBehavior(ga.gameEvents.MouseDown, "", ryu, "walkForward", moveToMouse, playInfinite);
   ga.addEventBehavior(ga.gameEvents.MouseUp, "", ryu, "ryu", resetMove, playInfinite);

   ga.addEventBehavior(ga.gameEvents.KeyDown, UPARROW, ryu, "walkForward", ryu.moveUp, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyDown, DOWNARROW, ryu, "walkBack", ryu.moveDown, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyUp, UPARROW, ryu, "ryu", null, playInfinite);
   ga.addEventBehavior(ga.gameEvents.KeyUp, DOWNARROW, ryu, "ryu", null, playInfinite);

   ga.addEventBehavior(ga.gameEvents.KeyDown, SPACEBAR, ryu, "attack", setRyuAttack, 1);
   ga.addEventBehavior(ga.gameEvents.KeyUp, SPACEBAR, ryu, "ryu", setRyuNormal, playInfinite);

This portion of code is wiring up keyboard, and touch interfaces for the player to control the "Ryu" sprite character. The parameters to addEvenBehavior are as follows:

  • The event to key off of as defined in GamesEvents.js (more on this to follow)
  • An event modifier to optionally leverage
  • The sprite that will key off of the event
  • The sprite's animation that should trigger on the event
  • The function to execute when the event occurs
  • The number of times to "execute this action"

Lets look at the different supported events to start:

this.NPC = "NPC";
this.Idle = "idle";
this.KeyDown = "keydown";
this.KeyUp = "keyup";
this.TouchStart = "touchstart";
this.TouchEnd = "touchend";
this.TouchMove = "touchmove";
this.MouseDown = "mousedown";
this.MouseUp = "mouseup";
this.MouseMove = "mousemove";
this.MouseClick = "mouseclick";

These are pretty much synonymous with the browsers events save for the addition of NPC and "idle".

  • NPC - indicates an NPC pulse has occurred and that NPCs should act in some way.
  • Idle - indicates that a player character is not currently doing anything.
  • Keydown - indicates a key press has occurred.
  • Keyup - a key up has occurred
  • TouchStart - A touch screen event has started
  • TouchMove - A touch screen drag has occurred.
  • MouseDown - A mouse down event has occurred
  • MouseUp - A mouse up event has occurred
  • MoveMove - A mouse move event has occurred.
  • MouseClick - A full mouse event has occurred.

By attaching these events to a given sprite, you can cause that sprite to behave in specific ways. Let's take a look at Ryu's attached events:

First off we have Ryu's idle state animation. Ie, this is what Ryu should be doing if the player hasn't keyed in any function.

    ga.addEventBehavior(ga.gameEvents.Idle, "", ryu, "ryu", null, tc.constants.playInfinite);

Here we are saying - when the Idle event is triggered (which is all the time), animate the sprite "ryu" (passed in as a reference), using the sprite animation named "ryu" (note, the names don't need to coincide, this can be whatever you named your animation, ie it could have been "doingnothing" I just happened to name my idle state the sprite name). Because there is no particular function I want to invoke on idle, the next parameter is blank and I tell the engine to play this animation in a loop infinitely via tc.constants.playInfinite (which = -1).

But what if we want something to happen? Let's look at Ryu punching. Here when the user hits the space bar (or does a double screen touch) we want Ryu to punch his opponent. To do this, we want to animate his attack sequence on the keydown and return him to idle on keyup. Let's look at this:

ga.addEventBehavior(ga.gameEvents.KeyDown, tc.constants.SPACEBAR, ryu, "attack", setRyuAttack, 1);
ga.addEventBehavior(ga.gameEvents.KeyUp, tc.constants.SPACEBAR, ryu, "ryu", setRyuNormal, tc.constants.playInfinite);

Here we have similar code, but this time we pass in keydown and keyup events. Note, we've also passed a modifier indicating the key in question (spacebar). We then also pass the sprite, but this time use the "attack" animation to indicate that the sprite should switch from the idle animation into the attacking state. Then we also pass a simple behavior function to set the sprite into the attack state (this is part of this particular game, not the engine). Last we pass in the number 1 to indicate that this animation should be played a single time.

The second call essentially tell the engine to set Ryu back to the idle state on keyup.

A more complex example can be viewed in examples/Isometric.html. In this example, you can see we use a class behavior. Behaviors are essentially javascript classes that implement a similar interface and encapsulate the AI or behavior for a given character. In our example we create two behaviors and attach them to our PC and NPC.

    var spriteSeeker = new SpriteSeeker("walking", "attacking", 100, hero);
    var originSeeker = new OriginSeeker("walking", "normal", "attacking", 100);

    ga.addEventBehavior(ga.gameEvents.MouseDown, "", hero, "walking", originSeeker, playInfinite);
    ga.addEventBehavior(ga.gameEvents.NPC, "", zom, "walking", spriteSeeker, playInfinite);

We'll talk more about behaviors in subsequent sections of this document.

In addition to attaching events to sprites, you can simply set global events that you control in your game code. For example in Isometric.html we allow a mousedown to highlight a given sprite (any sprite):

     ga.addEventBehavior(ga.gameEvents.MouseDown, undefined, undefined, undefined, function (e) {

            var spriteClick = ga.CheckEventPosition(e.offsetX, e.offsetY);

            if (spriteClick != undefined && spriteClick.name != "zombo") {  //if not our hero
                //highlight the sprite
                spriteClick.highLight(0, 0, 0, 0, 255, 0, 0, 0);
                this.lastClick = spriteClick;
                originSeeker.setTarget(spriteClick);
            }
            else {

                originSeeker.setTarget(undefined);
                if (this.lastClick != undefined) {
                    this.lastClick.unHighLight();
                }

            }
        }, 1);

Here we leave most of the parameters to addEventBehavior as undefined and capture the general event in our function param.

Frame level alerting

Sample: examples/TrafficConeTests.html

There may be times when you need granular control of given sprites animation sequence. For example, let's say you want to chain some animations or you want a certain event to happen on frame 6 out of 10 frames in an animation. To accomplish this in TC you can attach an animation watcher. For example, looking at the "watcherTests" function of TrafficConeTests.html you can see:

    var ng = ninjaGirl_Sprite(ga);
    ng.setTop(50);
    ng.setLeft(50);


    //anchor defaults bottom/left
    //apply hook to frame change
    ng.setWatcher("ninjaGirlNeutral", watcherTests, tc.constants.WATCH_TYPE_ALL_FRAME);
    ga.defineSprite( ng);

Here we create a sprite, set it's position and then set a watcher on the "ninjaGirlNeutral" animation. The second parameters passes a callback (which will receive a reference to the sprite) and instructions to use WATCH_TYPE_ALL_FRAME, which indicates to call the function on all frames. To watch a specific frame, pass in a numeric value representing the frame. It unfortunately doesn't support ranges right now. You can also supply WATCH_TYPE_LAST_FRAME to know when the animation is complete so that another can be chained.

Collision detection

See examples/2D or examples/Isometric.html

The engine class supports a method setCollisionHandler. This method receives a call back function which should receive two sprites (sprite1, and sprite2). Each animation frame the engine will check if any of your frames are colliding. If they are, this method will be fired in the order that the collisions are detected (not necessarily the order they occur). From there, you can add any game specific collision logic. In Isometric.html when we detect a collision we attach watchers to the end of a given animation and then augment the game logic accordingly. For example:

 ga.setCollisionHandler(function (sprite1, sprite2) {

[REMOVED FOR BREVITY]

     if (sprite1.getSpriteState() == "attacking") {
         sprite1.setWatcher("attacking", function () {
             sprite2Health -= 5;
             if (sprite2Health <= 0) {
                 sprite2.setWatcher("headsplode", function () {
                     ga.removeSprite("zombo1");
                 }, tc.constants.WATCH_TYPE_LAST_FRAME);                            
                 sprite2.setSpriteState("headsplode", undefined, true);
             }
             else {
                 sprite2.setSpriteState("hit");
             }
             sprite1.clearWatcher("attacking");
         }, tc.constants.WATCH_TYPE_LAST_FRAME);
     }


Here we check the state of the first sprite, if it is attacking we then attach a watcher to the sprite's last frame. As a result, when the attack animation is completed, the second sprite's health will be reduced. If the second sprite's health has reduced to 0, we attach a second watcher to it whereby when the death animation (headsplode) is complete, we remove the sprite from the game. We then set the 2nd sprites animation to headsplode. If the second sprite isn't dead, we set it's state to "gethit". In either case we clear the attackers watcher.

Background Textures (Ie, slimming things down for mobile)

See: examples/IOSTextureExperiments.html

In various examples we have set one or more sprites as cells for a background in an isometric game. However, each of these cells ends up being a draw operation. Traffic Cone is optimized to only draw the changes in your game, so in most cases you can still get a superior framerate for game using this method. However, if you intend to "scroll" or "pan" the background, traffic cone will be forced to redraw each cell of your background which on various mobile devices can cause a significant slow down. Luckily, html5 gives us the ability to set up a single texture as our background. Traffic cone takes advantage of this by allowing you to set a texture and then also set background cells the way your normally would. The result is much better draw performance. For example, if you were going to draw an outdoor sequence, you could set the texture to something grass like, and then use background sprites for trees, houses etc.

Our IOSTextureExperiements.html sample causes MkeIsoMetricGameWorld helper to invoke the engine's setUnderlayTexture method. This method sets a single given image as texture and instructs the engine to call the canvas' createPattern method under the hood. From there, your overlay and underlay background sprites are drawn on top of the texture.

AI, Path Finding and Behaviors

Coming soon see: examples/Isometric.html

Custom draw routines

Supporting code is in: examples/TrafficConeTests.html

License:

Traffic Cone is licensed under the MIT license. For details please see: http://en.wikipedia.org/wiki/MIT_License

Copyright (c) 2012 Joseph Mordetsky http://github.com/j03m

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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