Sunday, April 17, 2016

Phaser tutorial: Using Spriter player for Phaser

 





Previous Phaser tutorials and articles:
Phaser tutorial: Merging fonts into sprite atlas
Phaser: Typescript defs for Phaser Box2D plugin
Phaser tutorial: Spriter Pro features added to Spriter player for Phaser
Phaser tutorial: Using Phaser signals
Phaser tutorial: Breaking the (z-order) law!
Phaser tutorial: Phaser and Spriter skeletal animation
Phaser tutorial: DronShooter - simple game in Typescript - Part 3
Phaser tutorial: DronShooter - simple game in Typescript - Part 2
Phaser tutorial: adding 9-patch image support to Phaser
Phaser tutorial: DronShooter - simple game in Typescript - Part 1
Phaser tutorial: custom easing functions for tweening and easing functions with parameters
Phaser tutorial: sprites and custom properties for atlas frames
Phaser tutorial: manage different screen sizes
Phaser tutorial: How to wrap bitmap text



Introduction


 Some time ago I published here article about Spriter player for Phaser. I made the code freely available at GitHub. Player is written in Typescript and GitHub code contained both the player and small example on how to use it in one project. I thought it would be easy for others to use it, but I was wrong - for some coders it would be better if there was separate .js file and also there was lack of information on usage. But if you want to have nice animations in your game like the parrot above, small obstacles should not discourage you!
 
 So, I made a few changes - check GitHub:
  • player itself and example are both separated from each other,
  • there is added Build folder, where you can grab either spriter.js or spriter.min.js files ready to be used in your project.
 Splitting player and example also forced creation of Typescript defs for player. It can be found in spriter.d.ts file in Build directory.


Example


 I assume you are familiar with Phaser states. On GitHub go into Test/src/States. In Preloader.ts file I am loading export from Spriter program with standard Phaser loader. Export can by either .xml (.scml) od .json (scon). I am also loading atlas with all part visual parts of animation (for test use files from assets folder):

            // load assets
            var path: string = Global.assetsPath;

            // test
            this.load.atlas("TEST", path + "Atlas.png", path + "Atlas.json");
            this.load.xml("TESTXml", path + "TEST.xml");
            this.load.json("TESTJson", path + "TEST.json");

 You will need only to load either xml or json. Both lines are here only to show both possibilities. 

 What is important, Spriter exports list of visual parts with file extension like "head.png". Spriter player cuts the extension off and uses only part name (like "head"). Some tools for making sprite atlases export names with and some without extension. Make sure, that you create atlas with names without extension.

 When your data are loaded you can move to file Test.ts, where we will use it.

 First, we will do some basic setup. Data we loaded in previous step are either .xml or .json. But we need to turn it into some structure player is familiar with. To do it there is Spriter.Loader class. This class takes Spriter.SpriteFile (which can be Spriter.SpriterXml or Spriter.Spriter.JSON) and outputs complete Spriter.Spriter data structure. Loader can process as many files as you need - you do not need to create it for every single processing. All Spriter player classes are in Spriter namespace, so I will not further write it here.

 Let's create loader:

            // create Spriter loader - class that can change Spriter file into internal structure
            var spriterLoader = new Spriter.Loader();

 Now, we will create SpriterFile that loader can proces. It is one of derived classes - SpriterXml or SproterJSON (this time I will choose JSON and leave XML commented out):

            // create Spriter file object - it wraps XML/JSON loaded with Phaser Loader
            //var spriterFile = new Spriter.SpriterXml(this.cache.getXML("TESTXml"));
            var spriterFile = new Spriter.SpriterJSON(this.cache.getJSON("TESTJson"));

 Spriter files are way how to wrap data, so single loader class can ask for information so different formats like JSON or XML in some uniform way. (By the way, there is also possibility to load special binary format through SpriterBin, but this feature is not currently working as I have to add Spriter Pro features into it.)

 In next step we will pass our spriter file to loader and in output we get "unpacked" structure with all objects needed for animation (which sprites it uses, what charmaps are available, list of entities, animations, timelines, ...). This structure is "read only" and no data are stored in it. It means you can use it for many animations running simultaneously on screen.

 In last step we will create the animation itself. For this, player has SpriterGroup object. It extends standard Phaser.Group class. So, everything you can do with Phaser.Group, you can also do with SpriterGroup (scale, rotate, blend, ...). SpriterGroup is main class of Spriter player and most of the things you will need is done through this class (create _spriterGroup variable, so you can reference your animation later):

            // create actual renderable object - it is extension of Phaser.Group
            this._spriterGroup = new Spriter.SpriterGroup(this.game, spriterData, "TEST", "Hero", 0, 100);
            this._spriterGroup.position.setTo(420, 400);

            // adds SpriterGroup to Phaser.World to appear on screen
            this.world.add(this._spriterGroup);

 To tick animation add this into update method:

        update() {
            this._spriterGroup.updateAnimation();
        }

 This is little stupid, because Phaser calls update on Phaser.Group automatically. So, if animation update was in update method of SpriterGroup and not in updateAnimation, then this call would not be needed. I will probably change it in future. Until, you have to tick your animations explicitly.

 Running the example now, you should have animated character on screen. If you used assets from test, you will see this boy:


SpriterGroup features


 As already said, main class is SpriterGroup. So, I will go through its features here. I will use Typescript syntax as it includes type information, but it should be perfectly readable also for JS developers (take it as pseudocode).

 In example above we created new SpriterGroup like this:

this._spriterGroup = new Spriter.SpriterGroup(this.game, spriterData, "TEST", "Hero", 0, 100);

 Here is what these parameters mean:

        constructor(game: Phaser.Game, spriter: Spriter, texutreKey: string, entityName: string,
            animation?: string | number, animationSpeedPercent?: number);

 You need to pass Phaser.Game like for many other Phaser gameobjects. Next you have to pass Spriter animation structure that you processed with Spriter Loader class. Third is name of atlas with visual parts of animation. Last mandatory parameter is name of entity. Spriter file can have one or more entities. When you create SpriterGroup you have to pass which entity you want to use. You can not change this later.
 If you omit animation then first animation for entity is started. Every entity has one or more animations. Animations within entity can be switched. Last parameter is speed of animation in percent. default value is 100.

 SpriterGroup can inform you on a few events. This is done through standard Phaser.Signals. Here is list of signals you can use:

        // onLoop(SpriterGroup);
        onLoop: Phaser.Signal;
        // onFinish(SpriterGroup);
        onFinish: Phaser.Signal;

        // onSound(SpriterGroup, string); // string for line name which equals soud name without extension
        onSound: Phaser.Signal;
        // onEvent(SpriterGroup, string); // string for line name which equals event name
        onEvent: Phaser.Signal;
        // onTagChange(SpriterGroup, string, boolean); // string for tag name, boolean for change (true = set / false = unset)
        onTagChange: Phaser.Signal;
        // onVariableSet(SpriterGroup, Variable); // Variable is Spriter variable def with access to value
        onVariableSet: Phaser.Signal;

  • onLoop - subscribers are notified when animation loops,
  • onFinish - if animation does not loop, subscribers are notified on finishing,
  • onSound - Spriter Pro animations can have soundline, which allows great synchronization between animation and sounds. Spriter player does not actually play sounds, but notifies subscribers when sound shall be played. Signal dispatches SpriterGroup that fired event and name of  sound to play. In this way it is just specific sound event,
  • onEvent - in this Spriter player implementation it is the same as onSound, but not sound specific. Also here, name of the event is dispatched,
  • onTagChange - tags in Spriter animation says that something is on or off. When this changes you can read it through this signal. Imagine for example starting / stopping particle rain from sky when wizard casts spell (during "castRain" tag on). In this signal you get not only name of tag, but also its on/off state in next parameter,
  • onVariableSet - Spriter Pro animations can have variables, that are set in certain points to certain values. These variables are integers, floats and strings. Current implementation does not interpolate integer and float variables. Currently, it is only set to new value. You can listen to these events when variable is set and do something with its value. You can treat it as "event with value". Here you get Variable object that holds name, type and value.

 Here are few properties you can read:

        // get loaded Spriter structure
        spriter: Spriter;
        // get Spriter entity
        entity: Entity;
        // number of animations for current entity
        animationsCount: number;
        // name of current animation
        currentAnimationName: string;

 pause can be read and set:

        // is anim paused?
        paused: boolean;

 To play or change animation, set its playing speed and to update (tick) whole SpriterGroup, use these methods:

        // set speed of animation in percent (default = 100)
        setAnimationSpeedPercent(animationSpeedPercent: number): void;
        // play animation by Spriter animation id
        playAnimationById(aAnimationId: number): void;
        // play animation by name
        playAnimationByName(aAnimationName: string): void;
        // call this on every frame to tick animation
        updateAnimation(): void;

 Next set of method allows you to work with charmaps. Charmaps are sets of alternative visuals for animation (you can replace only some visuals). These charmaps can be stacked on each other. As a result you can achieve high variability with small amount of assets. Imagine evil orc as base character and charmap for replacing club with rusty sword and another charmap for helmet.

        // add charmap on top of charmap stacky by name
        pushCharMap(charMapName: string): void;
        // remove charmap from stack by name
        removeCharMap(charMapName: string): void;
        // remove all charmaps from charmap stack
        clearCharMaps(): void;

 With last set of methods you can question tags and variables:

        // check if animation tag with given name is on or off
        isTagOn(tagName: string): boolean;
        // check if animation tag with given id is on or off
        isTagOnById(tagId: number): boolean;
        // get animation variable by name
        getVariable(varName: string): Variable;
        // get animation variable by id
        getVariableById(varId: number): Variable;
        // get Spriter object by name - Spriter object contain actual Phaser.Sprite
        getObject(objectName: string): SpriterObject;


Conclusion


 I hope this tutorial helped to clarify some point, that were not clear before. Using Spriter animation as just another Phaser gameobject should be convenient. More, you can use all Phaser.Group methods with it.