iwmlib/lib/pixi/deepzoom/tile.js

/* ES Lint  */
/* globals PIXI, console*/

const registeredTiles = new Map()
/** Implements a baseTexture cache. The last textures are kept for reuse  */
let keepTextures = 0
const keptTextures = []
const lateTextures = new Map()
let lastSweepTime = 0
let sweepInterval = 2000.0

/** The current Tile implementation simply uses PIXI.Sprites.
 *
 * BTW: PIXI.extras.TilingSprite is not appropriate. It should be used for
 * repeating patterns.
 **/
export default class Tile extends PIXI.Sprite {
    constructor(texture, url) {
        super(texture)
        this.url = url
        this.register(url)
    }

    /**
     * Static method to enable keeping of base textures
     *
     * @static
     * @param {*} value
     * @memberof Tile
     */
    static enableKeepTextures(value = 1000) {
        keepTextures = value
    }

    /**
     * Returns true iff the url is pending
     *
     * @static
     * @param {*} url
     * @returns
     * @memberof Tile
     */
    /*static isPending(url) {
        return pendingTiles.has(url) && pendingTiles.get(url) > 0
    } */

    static isObsolete(url) {
        if (registeredTiles.has(url) && registeredTiles.get(url) > 0) {
            return false
        }
        return true
    }

    /**
     * Loads a tile from image using the PIXI.Texture.fromImage method.
     *
     * @static
     * @param {*} imageId
     * @param {*} crossorigin
     * @param {*} scaleMode
     * @returns
     * @memberof Tile
     */
    static fromImage(imageId, crossorigin, scaleMode) {
        return new Tile(PIXI.Texture.fromImage(imageId, crossorigin, scaleMode), imageId)
    }

    /**
     * Registers the tile in the global reference counter for textures
     *
     * @param {*} url
     * @param {boolean} [debug=false]
     * @memberof Tile
     */
    register(url, debug = false) {
        //Tile.unschedule(url)
        if (registeredTiles.has(url)) {
            let tiles = registeredTiles.get(url)
            tiles.add(this)
            if (debug) console.log("Tile.register", url, tiles.size)
        }
        else {
            registeredTiles.set(url, new Set([this]))
            if (debug) console.log("Tile.register", url, 1)
        }
    }

    /**
     * Unregisters the rile in the global reference counter for textures
     *
     * @returns {number} The number of how often a texture is used.
     * @memberof Tile
     */
    unregister() {
        let tiles = registeredTiles.get(this.url)
        tiles.delete(this)
        if (tiles.size == 0) {
            registeredTiles.delete(this.url)
            return 0
        }
        return tiles.size
    }

    /**
     * Destroys this sprite and optionally its texture and children
     *
     * @param {*} options  Part of the PIXI API, but ignored in the implementation
     * @memberof Tile
     */
    destroy(options, debug = false) {
        let count = this.unregister()

        if (keepTextures > 0) {
            keptTextures.push({ url: this.url, texture: this.texture })

            let opts = { children: true, texture: false, baseTexture: false }
            if (debug) console.log("Tile.destroy", registeredTiles.size, opts)
            super.destroy(opts)

            while (keptTextures.length > keepTextures) {
                let { url, texture } = keptTextures.shift()
                if (Tile.isObsolete(url)) {
                    texture.destroy(true) // Destroy base as well
                    if (debug) console.log("Destroying texture and baseTexture", url)
                }
            }
        }
        else {
            // No longer registered and not pending
            if (count <= 0) { // && !Tile.isPending(this.url)
                let opts = { children: true, texture: true, baseTexture: true }
                super.destroy(opts)
                if (debug) console.log("Tile.destroy", registeredTiles.size, opts)
            }
            else {
                let opts = { children: true, texture: false, baseTexture: false }
                if (debug) console.log("Tile.destroy", registeredTiles.size, opts)
                super.destroy(opts)
            }
            if (this.parent != null) {
                // UO: Emit warning and remove
                console.warn("Destroying tile with parent. Hiding instead")
                this.visible = false
            }
        }
    }

    /**
     * Returns an available texture that can be reused
     *
     * @param {*} url
     * @returns
     * @memberof Tile
     */
    static textureAvailable(url) {
        if (registeredTiles.has(url)) {
            let tiles = registeredTiles.get(url)
            for (let tile of tiles.values()) {
                //console.log("Reusing cached texture", tile.parent)
                return tile.texture
            }
        }
        return null
    }

    /**
     * Specialized renderWebGL to avoid freezing system
     *
     * @param {*} renderer
     * @memberof Tile
     */
    renderWebGL(renderer) {
        try {
            super.renderWebGL(renderer)
        }
        catch (e) {
            // We want persistent logging here
            Logging.error("Error in Tile.renderWebGL: " + e.message)
        }
    }

    /**
     * Removes lately arrived texture if they have not been touched in the meanwhile.
     *
     * @static
     * @memberof Tile
     */
    static sweepLateTextures() {
        let now = performance.now()
        if (now > lastSweepTime + sweepInterval) {
            lastSweepTime = now
            let count = 0
            for (let [url, texture] of lateTextures.entries()) {
                if (texture) {
                    let base = texture.baseTexture
                    if (base != null && base.touched == 0) {
                        texture.destroy(true)
                        //console.info("Sweeping ", url)
                        count += 1
                        lateTextures.delete(url)
                    }
                }
            }
            if (count > 0)
                console.log("Sweeping textures", count)
        }
    }

    /**
     * Texture received too late. We do not need it.
     * @param {*} url 
     * @param {*} texture 
     */
    static lateTexture(url, texture) {
        lateTextures.set(url, texture)
        //console.warn("Tile.lateTexture")
        // We cannot destroy the texture since we got errors in t.renderWebGL.
        // Perhaps we can destroy unsed textures later on
        Tile.sweepLateTextures()
    }

    static printInfos() {
        let references = new Map()
        let multiples = 0
        for (let [url, tiles] of registeredTiles.entries()) {
            let count = tiles.size
            references.set(url, count)
            if (count > 1) {
                multiples += 1
            }
        }
        console.log({ multiples, references })
    }
}