Class UISpriteElement

This is a basic sprite based button which you can use in your Game UI.

Hierarchy (view full)

Constructors

  • Parameters

    • x: number

      the x coordinate of the UISpriteElement Object

    • y: number

      the y coordinate of the UISpriteElement Object

    • settings: object

      See Sprite

    Returns UISpriteElement

    // create a basic GUI Object
    class myButton extends UISpriteElement {
    constructor(x, y) {
    // call the UISpriteElement parent constructor
    super(x, y, {
    image: "button",
    framewidth: 100,
    frameheight: 50
    });
    }

    // output something in the console
    // when the object is clicked
    onClick(event) {
    console.log("clicked!");
    // don't propagate the event
    return false;
    }
    });

    // add the object at pos (10,10)
    world.addChild(new myButton(10,10));

Properties

GUID: string

(G)ame (U)nique (Id)entifier"
a GUID will be allocated for any renderable object added
to an object container (including the me.game.world container)

alpha: number

Define the renderable opacity
Set to zero if you do not wish an object to be drawn

  • Renderable#setOpacity
  • Renderable#getOpacity
1.0
alwaysUpdate: boolean

Whether the renderable object will always update, even when outside of the viewport

false
ancestor: Container | Entity

a reference to the parent object that contains this renderable

undefined
anchorPoint: ObservablePoint

The anchor point is used for attachment behavior, and/or when applying transformations.
The coordinate system places the origin at the top left corner of the frame (0, 0) and (1, 1) means the bottom-right corner

a Renderable's anchor point defaults to (0.5,0.5), which corresponds to the center position.

Note: Object created through Tiled will have their anchorPoint set to (0, 0) to match Tiled Level editor implementation. To specify a value through Tiled, use a json expression like json:{"x":0.5,"y":0.5}.

<0.5,0.5>
anim: {}
animationpause: boolean
false
animationspeed: number

animation cycling speed (delay between frame in ms)

100
atlasIndices: any
autoTransform: boolean

When enabled, an object container will automatically apply any defined transformation before calling the child draw method.

true
// enable "automatic" transformation when the object is activated
onActivateEvent: function () {
// reset the transformation matrix
this.currentTransform.identity();
// ensure the anchor point is the renderable center
this.anchorPoint.set(0.5, 0.5);
// enable auto transform
this.autoTransform = true;
....
}
blendMode: string

the blend mode to be applied to this renderable (see renderer setBlendMode for available blend mode)

"normal"
  • CanvasRenderer#setBlendMode
  • WebGLRenderer#setBlendMode
body: Body

the renderable physic body

// define a new Player Class
class PlayerEntity extends me.Sprite {
// constructor
constructor(x, y, settings) {
// call the parent constructor
super(x, y , settings);

// define a basic walking animation
this.addAnimation("walk", [...]);
// define a standing animation (using the first frame)
this.addAnimation("stand", [...]);
// set the standing animation as default
this.setCurrentAnimation("stand");

// add a physic body
this.body = new me.Body(this);
// add a default collision shape
this.body.addShape(new me.Rect(0, 0, this.width, this.height));
// configure max speed, friction, and initial force to be applied
this.body.setMaxVelocity(3, 15);
this.body.setFriction(0.4, 0);
this.body.force.set(3, 0);
this.isKinematic = false;

// set the display to follow our position on both axis
me.game.viewport.follow(this.pos, me.game.viewport.AXIS.BOTH);
}

...

}
current: {
    angle: number;
    height: number;
    idx: number;
    length: number;
    name: undefined;
    offset: Vector2d;
    width: number;
}
currentTransform: Matrix2d

the renderable default transformation matrix

dt: number
edges: Vector2d[]

The edges here are the direction of the nth edge of the polygon, relative to the nth point. If you want to draw a given edge from the edge value, you must first translate to the position of the starting point.

floating: boolean

If true, this renderable will be rendered using screen coordinates, as opposed to world coordinates. Use this, for example, to define UI elements.

false
height: any
holdThreshold: number

Tap and hold threshold timeout in ms

250
holdTimeout: number
hover: boolean

true if the pointer is over the object

false
indices: number[]

a list of indices for all vertices composing this polygon

isClickable: boolean

object can be clicked or not

true
isDirty: boolean

when true the renderable will be redrawn during the next update cycle

true
isHoldable: boolean

object can be tap and hold

false
isKinematic: boolean

If true then physic collision and input events will not impact this renderable

true
isPersistent: boolean

make the renderable object persistent over level changes

false
isVideo: boolean

true if this is a video sprite (e.g. a HTMLVideoElement was passed as as source)

false
mask:
    | Polygon
    | Rect
    | Ellipse
    | Line
    | RoundRect

A mask limits rendering elements to the shape and position of the given mask object. So, if the renderable is larger than the mask, only the intersecting part of the renderable will be visible.

undefined
// apply a mask in the shape of a Star
myNPCSprite.mask = new me.Polygon(myNPCSprite.width / 2, 0, [
// draw a star
{x: 0, y: 0},
{x: 14, y: 30},
{x: 47, y: 35},
{x: 23, y: 57},
{x: 44, y: 90},
{x: 0, y: 62},
{x: -44, y: 90},
{x: -23, y: 57},
{x: -47, y: 35},
{x: -14, y: 30}
]);
name: string

The name of the renderable

""
offset: Vector2d

global offset for the position to draw from on the source image.

<0.0,0.0>
onVisibilityChange: Function

an event handler that is called when the renderable leave or enter a camera viewport

undefined
this.onVisibilityChange = function(inViewport) {
if (inViewport === true) {
console.log("object has entered the in a camera viewport!");
}
};
points: Vector2d[]

Array of points defining the Polygon
Note: If you manually change points, you must call recalcafterwards so that the changes get applied correctly.

origin point of the Polygon

released: boolean
resetAnim: undefined | Function | ((...args: []) => Sprite)
shader: GLShader

(Experimental) an optional shader, to be used instead of the default built-in one, when drawing this renderable (WebGL only)

undefined
source: TextureAtlas

The source texture object this sprite object is using

textureAtlas: any
type: string = "Rectangle"

The shape type (used internally).

updateWhenPaused: boolean

Whether to update this object when the game is paused.

false
width: any

Accessors

  • get isFloating(): boolean
  • Whether the renderable object is floating (i.e. used screen coordinates), or contained in a floating parent container

    Returns boolean

    Renderable#floating

Methods

  • add an animation
    For fixed-sized cell sprite sheet, the index list must follow the logic as per the following example :

    Parameters

    • name: string

      animation id

    • index: string[] | number[] | object[]

      list of sprite index or name defining the animation. Can also use objects to specify delay for each frame, see below

    • Optionalanimationspeed: number

      cycling speed for animation in ms

    Returns number

    frame amount of frame added to the animation (delay between each frame).

    Sprite#animationspeed

    // walking animation
    this.addAnimation("walk", [ 0, 1, 2, 3, 4, 5 ]);
    // standing animation
    this.addAnimation("stand", [ 11, 12 ]);
    // eating animation
    this.addAnimation("eat", [ 6, 6 ]);
    // rolling animation
    this.addAnimation("roll", [ 7, 8, 9, 10 ]);
    // slower animation
    this.addAnimation("roll", [ 7, 8, 9, 10 ], 200);
    // or get more specific with delay for each frame. Good solution instead of repeating:
    this.addAnimation("turn", [{ name: 0, delay: 200 }, { name: 1, delay: 100 }])
    // can do this with atlas values as well:
    this.addAnimation("turn", [{ name: "turnone", delay: 200 }, { name: "turntwo", delay: 100 }])
    // define an dying animation that stop on the last frame
    this.addAnimation("die", [{ name: 3, delay: 200 }, { name: 4, delay: 100 }, { name: 5, delay: Infinity }])
    // set the standing animation as default
    this.setCurrentAnimation("stand");
  • Returns true if the polygon contains the given point.
    (Note: it is highly recommended to first do a hit test on the corresponding
    bounding rect, as the function can be highly consuming with complex shapes)

    Parameters

    • x: number

      x coordinate or a vector point to check

    • y: number

      y coordinate

    Returns boolean

    True if the polygon contain the point, otherwise false

    if (polygon.contains(10, 10)) {
    // do something
    }
    // or
    if (polygon.contains(myVector2d)) {
    // do something
    }
  • Returns true if the polygon contains the given point.
    (Note: it is highly recommended to first do a hit test on the corresponding
    bounding rect, as the function can be highly consuming with complex shapes)

    Parameters

    Returns boolean

    True if the polygon contain the point, otherwise false

    if (polygon.contains(10, 10)) {
    // do something
    }
    // or
    if (polygon.contains(myVector2d)) {
    // do something
    }
  • Returns true if the rectangle contains the given rectangle

    Parameters

    • rectangle: Rect

      rectangle to test

    Returns boolean

    True if the rectangle contain the given rectangle, otherwise false

    if (rect.containsRectangle(myRect)) {
    // do something
    }
  • make the object flicker

    Parameters

    • duration: number

      expressed in milliseconds

    • Optionalcallback: Function = undefined

      Function to call when flickering ends

    Returns Sprite

    Reference to this object for method chaining

    // make the object flicker for 1 second
    // and then remove it
    this.flicker(1000, function () {
    world.removeChild(this);
    });
  • Returns true if the vertices composing this polygon form a convex shape (vertices must be in clockwise order).

    Returns null | boolean

    true if the vertices are convex, false if not, null if not computable

  • onCollision callback, triggered in case of collision, when this renderable body is colliding with another one

    Returns boolean

    true if the object should respond to the collision (its position and velocity will be corrected)

    // colision handler
    onCollision(response) {
    if (response.b.body.collisionType === me.collision.types.ENEMY_OBJECT) {
    // makes the other object solid, by substracting the overlap vector to the current position
    this.pos.sub(response.overlapV);
    this.hurt();
    // not solid
    return false;
    }
    // Make the object solid
    return true;
    },
  • Prepare the rendering context before drawing (automatically called by melonJS). This will apply any defined transforms, anchor point, tint or blend mode and translate the context accordingly to this renderable position.

    Parameters

    Returns void

    • Renderable#draw
    • Renderable#postDraw
  • scale the renderable around his anchor point. Scaling actually applies changes to the currentTransform member wich is used by the renderer to scale the object when rendering. It does not scale the object itself. For example if the renderable is an image, the image.width and image.height properties are unaltered but the currentTransform member will be changed.

    Parameters

    • x: number

      a number representing the abscissa of the scaling vector.

    • Optionaly: number = x

      a number representing the ordinate of the scaling vector.

    Returns Renderable

    Reference to this object for method chaining

  • set the current animation this will always change the animation & set the frame to zero

    Parameters

    • name: string

      animation id

    • OptionalresetAnim: string | Function

      animation id to switch to when complete, or callback

    • Optionalpreserve_dt: boolean = false

      if false will reset the elapsed time counter since last frame

    Returns Sprite

    Reference to this object for method chaining

    // set "walk" animation
    this.setCurrentAnimation("walk");

    // set "walk" animation if it is not the current animation
    if (this.isCurrentAnimation("walk")) {
    this.setCurrentAnimation("walk");
    }

    // set "eat" animation, and switch to "walk" when complete
    this.setCurrentAnimation("eat", "walk");

    // set "die" animation, and remove the object when finished
    this.setCurrentAnimation("die", () => {
    world.removeChild(this);
    return false; // do not reset to first frame
    });

    // set "attack" animation, and pause for a short duration
    this.setCurrentAnimation("die", () => {
    this.animationpause = true;

    // back to "standing" animation after 1 second
    setTimeout(function () {
    this.setCurrentAnimation("standing");
    }, 1000);

    return false; // do not reset to first frame
    });
  • change the current texture atlas region for this sprite

    Parameters

    • region: object

      typically returned through me.Texture.getRegion()

    Returns Sprite

    Reference to this object for method chaining

    Texture.getRegion

    // change the sprite to "shadedDark13.png";
    mySprite.setRegion(mytexture.getRegion("shadedDark13.png"));