在3D场景中显示汉字

TWaver 3D for Flex本身支持3D文字的显示，但是用户必须嵌入一套字库才可以。使用传统的方式，显示3D文字。

[Embed("extrusionfonts.swf", mimeType="application/octet-stream")]
private var font:Class;
.....
twaver.threed.util.Util3D.checkTextFont(font);
var network:Network3D = new Network3D();
network.applyHoverCamera(-180,10,5,300);
this.addElement(network);
var n2:Node = new Node();
n2.setStyle(Style3D.THREED_SHAPE_TYPE,Consts3D.THREED_SHAPE_TYPE_TEXT);
n2.setStyle(Style3D.TEXT_FONT_SIZE,20);
n2.setStyle(Style3D.TEXT_FONT_3D,"Arial");
n2.setStyle(Style3D.TEXT_WIDTH,200);
n2.setStyle(Style3D.TEXT_CONTENT,"Hello");
n2.setStyle(Style3D.MAPPINGTYPE,Consts3D.MAPPINGTYPE_COLOR);
n2.setStyle(Style3D.MATERIAL_COLOR,0x00FF00);
n2.setStyle(Style3D.PROPERTY_SPACE_LOCATION,new Vector3D(100,0,0));
n2.setStyle(Style3D.BOTH_SIDES_VISIBLE,true);
network.elementBox.add(n2);
network.showAxises();

　　

对于国内客户来说，这一点就有些痛苦了，一个中文字库的体积太大，嵌入发布程序中的话，会增大发布包的大小，及时是远程加载，也会因为其恐怖的体积，让用户的web化设计面临网络情况的挑战。当然为了用户也可以去裁剪一个字库，把自己会用到的文字收入其中，做个可控数量级的枚举，但是实时系统在运行过程中，会碰到什么样的汉字也是个未知，很难做裁剪的时候枚举尽所需要的汉字。这个问题一直苦苦萦绕在每个人的心头。

，，，，，，

，，，，，，

终于，TWaver 3D支持动态贴图了，这里的动态贴图已经不只是说可以动态切换贴图资源的来源，更重要的是可以动态切换上在内存中生成的BitmapData对象。大家都知道，Flex的BitmapData支持将其UIComponent绘制出来，这一下子为我们解决汉字显示提供了一个非常便捷的方式，那就是我们把汉字写进一个TextInput组件中去，然后再把这个组件画到一个BitmapData对象中，然后在将这个对象变成我们一个3D对象的贴图（例如一个Plane，一个Billboard，一个Cube等等）。ok，动手试验

按步就班，搭建一个3D场景，并且放入一个Plane对象。 

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
			   xmlns:s="library://ns.adobe.com/flex/spark"
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:ns="http://www.servasoft.com/twaver/3D" creationComplete="init()">
	<fx:Declarations>
		<!-- Place non-visual elements (e.g., services, value objects) here -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import twaver.*;
			import twaver.threed.event.*;
			import twaver.threed.util.*;
			private var databox:ElementBox;
			private var source:BitmapData;
			private var rect:Rectangle = new Rectangle(0,0,128,128);
			private var text:TextInput = new TextInput();
			private var n1:Node;
			private function init():void{
				prepare();
				setupNetwork();
				fillData();
				network.showAxises();
				network.callLater(function():void{
					paintTexture(n1);
				});
			}
			private function fillData():void{
				n1 = NodeUtils.buildPlane(new Vector3D(0,0,0),new Vector3D(32,0,32),new Vector3D(90,0,0),Consts3D.MAPPINGTYPE_COMMON,source,true);
				databox.add(n1);
			}
			private function setupNetwork():void{
				databox = network.elementBox;
				network.applyHoverCamera(-180,10,5,200);
			}
		]]>
	</fx:Script>
	<ns:Network3D id="network" width="100%" height="100%"/>
</s:Application>

我们会得到一个类似截图的效果，一个只有一个plane对象的3D场景：

现在就让我们用点小技巧，把自己需要的汉字画到3D场景中去吧。

我们需要针对前面的代码做点改进，引入一个TextInput组件，用来呈现汉字；然后我们需要动态地生成一个BitmapData对象，把这个汉字画到指定的图片中去，最后我们再把内存里的这个画好了汉字的图片作为贴图，贴到plane上去。 

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
			   xmlns:s="library://ns.adobe.com/flex/spark"
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:ns="http://www.servasoft.com/twaver/3D" creationComplete="init()">
	<fx:Declarations>
		<!-- Place non-visual elements (e.g., services, value objects) here -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import mx.controls.TextInput;
			import twaver.*;
			import twaver.threed.event.*;
			import twaver.threed.util.*;
			private var databox:ElementBox;
			private var source:BitmapData;
			private var rect:Rectangle = new Rectangle(0,0,128,128);
			private var text:TextInput = new TextInput();
			private var n1:Node;
			private function init():void{
				prepare();
				setupNetwork();
				fillData();
				network.showAxises();
				network.callLater(function():void{
					paintTexture(n1);
				});
			}
			private function prepare():void{
				text.width = 150;
				text.height = 60;
				text.setStyle('borderStyle','none');
				text.text = "你好";
				text.alpha = 1;
				this.addElement(text);
				text.visible = false;
			}
			private function fillData():void{
				n1 = NodeUtils.buildPlane(new Vector3D(0,0,0),new Vector3D(32,0,32),new Vector3D(90,0,0),Consts3D.MAPPINGTYPE_COMMON,source,true);
				databox.add(n1);
			}
			private function setupNetwork():void{
				databox = network.elementBox;
				network.applyHoverCamera(-180,10,5,200);
			}
			private function setTexture(n:Element,source:BitmapData):void{
				var type:String = n.getStyle(Style3D.THREED_SHAPE_TYPE);
				switch(type){
					case Consts3D.THREED_SHAPE_TYPE_BILLBOARD:
						n.setStyle(Style3D.BILLBOARD_TEXTURE,source);
						break;
					case Consts3D.THREED_SHAPE_TYPE_PLANE:
						n.setStyle(Style3D.PLANE_MATERIAL,source);
						break;
					default:
						n.setStyle(Style3D.MAPPING_COMMON_PATH,source);
						break;
				}
			}
			private function paintTexture(n:Element):void{
				source = new BitmapData(32,32,true,0x00000000);
				text.text = n.getClient("label");
				source.fillRect(rect,0x00000000);
				source.draw(text);
				setTexture(n,source);
			}
		]]>
	</fx:Script>
	<ns:Network3D id="network" width="100%" height="100%"/>
</s:Application>　　

 再次运行，看看是不是能够得偿所愿。

吼吼，look，出来了，汉字出来了，没有引入任何字库，汉字就能够出现在我的3D场景中了。 8过，还是有些遗憾，那就是有时候如果让这汉字的内容动态地变化的时候，可怎么办？？

......

......

有了！我动态切换不就行了！？说干就干，抓紧验证，重新打造代码，添加动态变化。

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
			   xmlns:s="library://ns.adobe.com/flex/spark"
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:ns="http://www.servasoft.com/twaver/3D" creationComplete="init()">
	<fx:Declarations>
		<!-- Place non-visual elements (e.g., services, value objects) here -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import mx.controls.TextInput;
			import mx.events.PropertyChangeEvent;
			import twaver.*;
			import twaver.threed.event.*;
			import twaver.threed.util.*;
			private var databox:ElementBox;
			private var source:BitmapData;
			private var rect:Rectangle = new Rectangle(0,0,128,128);
			private var text:TextInput = new TextInput();
			private var n1:Node;
			private function init():void{
				prepare();
				setupNetwork();
				fillData();
				network.showAxises();
				network.callLater(function():void{
					paintTexture(n1);
				});

				var timer:Timer = new Timer(1000);
				timer.addEventListener(TimerEvent.TIMER,function(evt:Event):void{
					var date:Date = new Date();
					n1.setClient("label",date.seconds);
				});
				timer.start();
			}
			private function prepare():void{
				text.width = 150;
				text.height = 60;
				text.setStyle('borderStyle','none');
				text.text = "你好";
				text.alpha = 1;
				this.addElement(text);
				text.visible = false;
			}
			private function fillData():void{
				n1 = NodeUtils.buildPlane(new Vector3D(0,0,0),new Vector3D(32,0,32),new Vector3D(90,0,0),Consts3D.MAPPINGTYPE_COMMON,source,true);
				databox.add(n1);
			}
			private function setupNetwork():void{
				databox = network.elementBox;
				network.applyHoverCamera(-180,10,5,200);
				databox.addDataPropertyChangeListener(this.onPropertyChanged);
			}
			private function onPropertyChanged(evt:PropertyChangeEvent):void{
				var name:String = Util3D.getPropertyName(evt.property as String);
				if("label"==name){
					var element:Element = evt.source as Element;
					paintTexture(element);
				}
			}
			private function setTexture(n:Element,source:BitmapData):void{
				var type:String = n.getStyle(Style3D.THREED_SHAPE_TYPE);
				switch(type){
					case Consts3D.THREED_SHAPE_TYPE_BILLBOARD:
						n.setStyle(Style3D.BILLBOARD_TEXTURE,source);
						break;
					case Consts3D.THREED_SHAPE_TYPE_PLANE:
						n.setStyle(Style3D.PLANE_MATERIAL,source);
						break;
					default:
						n.setStyle(Style3D.MAPPING_COMMON_PATH,source);
						break;
				}
			}
			private function paintTexture(n:Element):void{
				source = new BitmapData(50,32,true,0x00000000);
				text.text = n.getClient("label");
				source.fillRect(rect,0x00000000);
				source.draw(text);
				setTexture(n,source);
			}
		]]>
	</fx:Script>
	<ns:Network3D id="network" width="100%" height="100%"/>
</s:Application>

run again! Please check you screen!

大家一起来看看，哪里还有可以改进的，让我们把3D应用做得更彻底一些。

这里是文章中用到的UsingChineseCharacter.mxml代码（见原文最下方）。