phaser
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A fast, free and fun HTML5 Game Framework for Desktop and Mobile web browsers.
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JavaScript
/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2018 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
var CONST = require('../../const');
var Smoothing = require('./Smoothing');
// The pool into which the canvas elements are placed.
var pool = [];
// Automatically apply smoothing(false) to created Canvas elements
var _disableContextSmoothing = false;
/**
* The CanvasPool is a global static object, that allows Phaser to recycle and pool 2D Context Canvas DOM elements.
* It does not pool WebGL Contexts, because once the context options are set they cannot be modified again,
* which is useless for some of the Phaser pipelines / renderer.
*
* This singleton is instantiated as soon as Phaser loads, before a Phaser.Game instance has even been created.
* Which means all instances of Phaser Games on the same page can share the one single pool.
*
* @namespace Phaser.Display.Canvas.CanvasPool
* @since 3.0.0
*/
var CanvasPool = function ()
{
/**
* Creates a new Canvas DOM element, or pulls one from the pool if free.
*
* @function Phaser.Display.Canvas.CanvasPool.create
* @since 3.0.0
*
* @param {*} parent - The parent of the Canvas object.
* @param {integer} [width=1] - The width of the Canvas.
* @param {integer} [height=1] - The height of the Canvas.
* @param {integer} [canvasType=Phaser.CANVAS] - The type of the Canvas. Either `Phaser.CANVAS` or `Phaser.WEBGL`.
*
* @return {HTMLCanvasElement} [description]
*/
var create = function (parent, width, height, canvasType)
{
if (width === undefined) { width = 1; }
if (height === undefined) { height = 1; }
if (canvasType === undefined) { canvasType = CONST.CANVAS; }
var canvas;
var container = first(canvasType);
if (container === null)
{
container = {
parent: parent,
canvas: document.createElement('canvas'),
type: canvasType
};
if (canvasType === CONST.CANVAS)
{
pool.push(container);
}
canvas = container.canvas;
}
else
{
container.parent = parent;
canvas = container.canvas;
}
canvas.width = width;
canvas.height = height;
if (_disableContextSmoothing && canvasType === CONST.CANVAS)
{
Smoothing.disable(canvas.getContext('2d'));
}
return canvas;
};
/**
* Creates a new Canvas DOM element, or pulls one from the pool if free.
*
* @function Phaser.Display.Canvas.CanvasPool.create2D
* @since 3.0.0
*
* @param {*} parent - The parent of the Canvas object.
* @param {integer} [width=1] - The width of the Canvas.
* @param {integer} [height=1] - The height of the Canvas.
*
* @return {HTMLCanvasElement} [description]
*/
var create2D = function (parent, width, height)
{
return create(parent, width, height, CONST.CANVAS);
};
/**
* Creates a new Canvas DOM element, or pulls one from the pool if free.
*
* @function Phaser.Display.Canvas.CanvasPool.createWebGL
* @since 3.0.0
*
* @param {*} parent - The parent of the Canvas object.
* @param {integer} [width=1] - The width of the Canvas.
* @param {integer} [height=1] - The height of the Canvas.
*
* @return {HTMLCanvasElement} [description]
*/
var createWebGL = function (parent, width, height)
{
return create(parent, width, height, CONST.WEBGL);
};
/**
* Gets the first free canvas index from the pool.
*
* @function Phaser.Display.Canvas.CanvasPool.first
* @since 3.0.0
*
* @param {integer} [canvasType=Phaser.CANVAS] - The type of the Canvas. Either `Phaser.CANVAS` or `Phaser.WEBGL`.
*
* @return {HTMLCanvasElement} [description]
*/
var first = function (canvasType)
{
if (canvasType === undefined) { canvasType = CONST.CANVAS; }
if (canvasType === CONST.WEBGL)
{
return null;
}
for (var i = 0; i < pool.length; i++)
{
var container = pool[i];
if (!container.parent && container.type === canvasType)
{
return container;
}
}
return null;
};
/**
* Looks up a canvas based on its parent, and if found puts it back in the pool, freeing it up for re-use.
* The canvas has its width and height set to 1, and its parent attribute nulled.
*
* @function Phaser.Display.Canvas.CanvasPool.remove
* @since 3.0.0
*
* @param {*} parent - [description]
*/
var remove = function (parent)
{
// Check to see if the parent is a canvas object
var isCanvas = parent instanceof HTMLCanvasElement;
pool.forEach(function (container)
{
if ((isCanvas && container.canvas === parent) || (!isCanvas && container.parent === parent))
{
container.parent = null;
container.canvas.width = 1;
container.canvas.height = 1;
}
});
};
/**
* Gets the total number of used canvas elements in the pool.
*
* @function Phaser.Display.Canvas.CanvasPool.total
* @since 3.0.0
*
* @return {integer} [description]
*/
var total = function ()
{
var c = 0;
pool.forEach(function (container)
{
if (container.parent)
{
c++;
}
});
return c;
};
/**
* Gets the total number of free canvas elements in the pool.
*
* @function Phaser.Display.Canvas.CanvasPool.free
* @since 3.0.0
*
* @return {integer} [description]
*/
var free = function ()
{
return pool.length - total();
};
/**
* Disable context smoothing on any new Canvas element created.
*
* @function Phaser.Display.Canvas.CanvasPool.disableSmoothing
* @since 3.0.0
*/
var disableSmoothing = function ()
{
_disableContextSmoothing = true;
};
/**
* Enable context smoothing on any new Canvas element created.
*
* @function Phaser.Display.Canvas.CanvasPool.enableSmoothing
* @since 3.0.0
*/
var enableSmoothing = function ()
{
_disableContextSmoothing = false;
};
return {
create2D: create2D,
create: create,
createWebGL: createWebGL,
disableSmoothing: disableSmoothing,
enableSmoothing: enableSmoothing,
first: first,
free: free,
pool: pool,
remove: remove,
total: total
};
};
// If we export the called function here, it'll only be invoked once (not every time it's required).
module.exports = CanvasPool();