pxt-common-packages/libs/game/spriteset.ts

Microsoft MakeCode (PXT) common packages

namespace sprites {
    /*
    * A set of sprites
    */
    export class SpriteSet {
        private _sprites: Sprite[];

        /**
         * Create a new set from an array of sprites
         * @param sprites
         */
        static createFromArray(sprites: Sprite[]): SpriteSet {
            const sp = new SpriteSet();
            const n = sprites.length;
            for (let i = 0; i < n; ++i)
                sp.add(sprites[i]);
            return sp;
        }

        constructor() {
            this._sprites = [];
        }

        /**
         * Gets the number of sprites in the set
         */
        get length() {
            return this._sprites.length;
        }

        /**
         * Gets the snapshot of the current list of sprites
         */
        sprites() {
            return this._sprites.filter(s => !(s.flags & sprites.Flag.Destroyed));
        }

        /**
         * Adds the sprite, returns true if added; false if the sprite was already in the set
         * @param sprite
         */
        add(sprite: Sprite): boolean {
            if (!sprite) return false; // don't add nulls

            // scan if in set
            if (this.contains(sprite))
                return false;
            this._sprites.push(sprite);
            return true;
        }

        /**
         * Adds sprite and removes from old set. Returns true if sprite was in old set and not in new set.
         * @param oldSet
         * @param sprite
         */
        addFrom(oldSet: SpriteSet, sprite: Sprite): boolean {
            const removed = oldSet.remove(sprite);
            const added = this.add(sprite);
            return removed && added;
        }

        /**
         * Removes sprite from set. Returns true if the sprite was in the set
         * @param sprite
         */
        remove(sprite: Sprite): boolean {
            const i = this._sprites.indexOf(sprite);
            if (i > -1) {
                this._sprites.splice(i, 1);
                return true;
            }
            return false;
        }

        /**
         * Checks if the sprite is part of the set
         * @param sprite
         */
        contains(sprite: Sprite): boolean {
            return this._sprites.indexOf(sprite) > -1;
        }

        /**
         * Removes all the sprites from the set
        */
        clear() {
            this._sprites.splice(0, this._sprites.length);
        }

        /**
         * Removes the last sprite in the set
         */
        pop(): Sprite {
            return this._sprites.pop();
        }

        toString() {
            return `${this.length} sprites`
        }
    }
}