Starling2.x SuperTextureAtlas 扩展支持4096以上的纹理集图片

前言

在开发游戏过程中，经常遇到图片达到4096的尺寸，如果去修改这个纹理集合分配成2048的话，会浪费不少的人力。所以，扩展了一个SuperTextureAtlas来支持大于4096的纹理集图片。

实现原理

其实原理很简单，也就是解析位图的大小，将超过尺寸的大图，切割成一个个2048的精灵表TextureAtlas。而SuperTextureAtlas正是重写了其获取方法，管理读取多个精灵表，所以能照常使用。此外，为了实现这个功能，特意修改了AssetsManager类的几个小地方。

SuperTextureAtlas.as源码

package zygame.utils{    import flash.display.BitmapData;    import flash.geom.Point;    import flash.geom.Rectangle;    import flash.system.System;    import starling.textures.Texture;    import starling.textures.TextureAtlas;    public class SuperTextureAtlas extends TextureAtlas    {        /**         * Whether to start support, the default is false         */             public static var support:Boolean = false;        private var _maxPack:Vector.<Object>;        private var _textureAtlas:Vector.<TextureAtlas>;        private var _separationCount:int = 0;        private var _separationIndex:int = 0;        private var _bitmapData:BitmapData;        private var _xml:XMLList;        private var _length:int = 0;        private var _count:int = 0;        public function SuperTextureAtlas(bitmapData:BitmapData,xml:XML):void        {            _bitmapData = bitmapData;            _xml = xml.children();            _length = _xml.length();            _textureAtlas = new Vector.<TextureAtlas>();            _maxPack = new Vector.<Object>();            _separationCount = 1;            while(_maxPack.length < _separationCount){                _maxPack.push(separation());            }            super(Texture.fromBitmapData(_maxPack[0].bitmapData),_maxPack[0].xml);            for(var c:int = 0;c<_maxPack.length;c++)            {                if(c != 0)                {                    var textureAtlas:TextureAtlas = new TextureAtlas(Texture.fromBitmapData(_maxPack[c].bitmapData),_maxPack[c].xml);                    _textureAtlas.push(textureAtlas);                }            }            _bitmapData = null;        }        /**         * Isolations, separate the texture set one by one, back together         * @return          *          */             private function separation():Object        {            var bitmapData:BitmapData = new BitmapData(2048,2048,true,0x0);            var pack:MaxRectsBinPack = new MaxRectsBinPack(2048,2048,false);            for(var i:int = _separationIndex;i<_length;i++)            {                var rect:Rectangle = pack.insert(int(_xml[i].@width),int(_xml[i].@height),2);                _count ++;                if(rect.width == 0 || rect.height == 0)                {                    _separationCount ++;                    break;                }            }            var newXML:XML = <xml></xml>;            for(var u:int = 0;u<pack.usedRectangles.length;u++)            {                bitmapData.copyPixels(_bitmapData,new Rectangle(int(_xml[_separationIndex+u].@x),int(_xml[_separationIndex+u].@y),int(_xml[_separationIndex+u].@width),int(_xml[_separationIndex+u].@height)),new Point(pack.usedRectangles[u].x,pack.usedRectangles[u].y));                var nodeXML:XML = _xml[_separationIndex+u].copy();                nodeXML.@x = pack.usedRectangles[u].x;                nodeXML.@y = pack.usedRectangles[u].y;                newXML.appendChild(nodeXML);            }            _separationIndex = i;            return {                bitmapData:bitmapData,                xml:newXML            };        }        override public function getTexture(name:String):Texture        {            var texture:Texture = super.getTexture(name);            if(texture)                return texture;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                texture = _textureAtlas[i].getTexture(name);                if(texture)                    return texture;            }            return null;        }        override public function getFrame(name:String):Rectangle        {            var rect:Rectangle = super.getFrame(name);            if(rect)                return rect;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                rect = _textureAtlas[i].getFrame(name);                if(rect)                    return rect;            }            return null;        }        override public function getRegion(name:String):Rectangle        {            var rect:Rectangle = super.getRegion(name);            if(rect)                return rect;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                rect = _textureAtlas[i].getRegion(name);                if(rect)                    return rect;            }            return null;        }        override public function getRotation(name:String):Boolean        {            var bool:Boolean = super.getRotation(name);            if(bool)                return true;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                bool = _textureAtlas[i].getRegion(name);                if(bool)                    return true;            }            return false;        }        override public function getNames(prefix:String="", out:Vector.<String>=null):Vector.<String>        {            var vec:Vector.<String> = super.getNames(prefix,out);            if(vec)                return vec;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                vec = _textureAtlas[i].getNames(prefix,out);                if(vec)                    return vec;            }            return null;        }        override public function getTextures(prefix:String="", out:Vector.<Texture>=null):Vector.<Texture>        {            var vec:Vector.<Texture> = super.getTextures(prefix,out);            if(vec)                return vec;            for(var i:int = 0;i<_textureAtlas.length;i++)            {                vec = _textureAtlas[i].getTextures(prefix,out);                if(vec)                    return vec;            }            return null;        }        override public function dispose():void        {            for(var c:int = 0;c<_textureAtlas.length;c++)            {                _textureAtlas[c].dispose();            }            for(var i:int = 0;i<_maxPack.length;i++)            {                (_maxPack[i].bitmapData as BitmapData).dispose();                System.disposeXML((_maxPack[i].xml as XML));            }            _maxPack.splice(0,_maxPack.length);            _maxPack = null;        }    }}

以上是实现原理，所有涉及源码晚些我放在CSND下载区。