scratch-vm/src/sprites/sprite.js

const RenderedTarget = require('./rendered-target');
const Blocks = require('../engine/blocks');

class Sprite {
    /**
     * Sprite to be used on the Scratch stage.
     * All clones of a sprite have shared blocks, shared costumes, shared variables.
     * @param {?Blocks} blocks Shared blocks object for all clones of sprite.
     * @param {Runtime} runtime Reference to the runtime.
     * @constructor
     */
    constructor (blocks, runtime) {
        this.runtime = runtime;
        if (!blocks) {
            // Shared set of blocks for all clones.
            blocks = new Blocks();
        }
        this.blocks = blocks;
        /**
         * Human-readable name for this sprite (and all clones).
         * @type {string}
         */
        this.name = '';
        /**
         * List of costumes for this sprite.
         * Each entry is an object, e.g.,
         * {
         *      skinId: 1,
         *      name: "Costume Name",
         *      bitmapResolution: 2,
         *      rotationCenterX: 0,
         *      rotationCenterY: 0
         * }
         * @type {Array.<!Object>}
         */
        this.costumes = [];
        /**
         * List of sounds for this sprite.
        */
        this.sounds = [];
        /**
         * List of clones for this sprite, including the original.
         * @type {Array.<!RenderedTarget>}
         */
        this.clones = [];
    }

    /**
     * Create a clone of this sprite.
     * @returns {!RenderedTarget} Newly created clone.
     */
    createClone () {
        const newClone = new RenderedTarget(this, this.runtime);
        newClone.isOriginal = this.clones.length === 0;
        this.clones.push(newClone);
        if (newClone.isOriginal) {
            newClone.initDrawable();
        }
        return newClone;
    }

    /**
     * Disconnect a clone from this sprite. The clone is unmodified.
     * In particular, the clone's dispose() method is not called.
     * @param {!RenderedTarget} clone - the clone to be removed.
     */
    removeClone (clone) {
        const cloneIndex = this.clones.indexOf(clone);
        if (cloneIndex >= 0) {
            this.clones.splice(cloneIndex, 1);
        }
    }
}

module.exports = Sprite;