bs-pixi

BuckleScript bindings for PixiJS v6 (Work in progress)

Refer to documentation for existing coverage.

Installation

npm install bs-pixi

And add bs-pixi into bs-dependencies in your project bsconfig.json.

About Bindings

PIXI.js relies heavily on inheritance, which in the context of bucklescript bindings is often realized via functors where module containing subclass functionality would "spread" the implementation of the ancestor module (closest is mixin) - see Extending Modules. This is often referred to as implementation inheritance. One example is in bs-webapi-incubator. In addition to this approach here we bind directly to javascript classes via bucklescript supported class type bindings, with most apis accepting all structural subtypes:

[@bs.send]
external addChild: (Js.t(#C.displayObject), ~child: Js.t(#C.displayObject as 'a)) => Js.t('a) = "addChild";

# denotes structural subtype, so when we see Js.t(#C.displayObjects) we can feed any js object types that are structural subtypes of displayObject directly without upcasting to a type which is defined in a module where addChild is defined. Also this allows us to utilize both functional as well as object apis for the same functionality like:

let point = PIXI.Point.create(~x=1.0, ~y=5.0, ());
let x = point##x;
let x = point |. PIXI.Point.getX;

Although using object methods for anything slightly more complex as simple accessors is not really practical, as [@bs] class object methods do not support currying, labeled and optional parameters, feel free to use it if you feel comfortable with it, as in next example.

Example

open PIXI;

let app = Application.create(~options=Application.createApplicationOptions(
  ~width=800.,
  ~height=600.,
  ~backgroundColor=int_of_string("0x1099bb"),
  ~resolution=DomRe.window |. Obj.magic |. Js.Dict.unsafeGet("devicePixelRatio"), ()), 
  ());

Webapi.Dom.document 
|> Webapi.Dom.Document.asHtmlDocument 
|. Belt.Option.flatMap(document => document |> Webapi.Dom.HtmlDocument.body)
|. Belt.Option.map(body => body |> Webapi.Dom.Element.appendChild(app##view))
|> ignore;

let container = Container.create();

app 
|. Application.getStage 
|. Container.addChild(container);

// Create a new texture
let texture = Texture.from(~source=`String("https://pixijs.io/examples/examples/assets/bunny.png"), ());

// Create a 5x5 grid of bunnies
Belt.Array.range(0, 24)
|. Belt.Array.forEach(i => {
  let bunny = Sprite.create(texture);
  bunny##anchor##set(0.5, 0.5);
  bunny |. Sprite.setX(float_of_int((i mod 5) * 40));
  bunny |. Sprite.setY(floor(float_of_int(i) /. 5.) *. 40.);
  container |. Container.addChild(bunny) |> ignore;
});

container |. Container.setX(app##screen##width /. 2.);
container |. Container.setY(app##screen##height /. 2.);

// Center bunny sprite in local container coordinates
container##pivot##x #= (container##width /. 2.);
container##pivot##y #= (container##height /. 2.);

// Listen for animate update
app
|. Application.getTicker
|. Ticker.add(delta => {
  // rotate the container!
  // use delta to create frame-independent transform
  container |. Container.setRotation(container##rotation -. 0.01 *. delta);
}, ());

Also make sure to CHECK OUT other examples.

Contributing

Any contribution is greatly appreciated. Take a look at CONTRIBUTING.md. Feel free to reach out in issues for any questions.