Flash 3D引擎（Sandy3D）应用指南 4a——使用灯光

原文地址：http://www.flashsandy.org/tutorials/3.0/sandy_cs3_tut041

 

指南目标

在这个指南里，我们决定展示Sandy关于灯光的功能。当你想使用每个对象的内置的灯光效果来渲染你的对象时。你可能满足于默认的设置，但你也可能希望可以修改灯光的强度或灯光的方向。在这里你将会学到怎么实现这些。

 

怎么做？

 代码如下example0041.rar ：

package {   import flash.display.Sprite;    import flash.events.*;   import flash.ui.*;    import sandy.core.Scene3D;   import sandy.core.data.*;   import sandy.core.scenegraph.*;   import sandy.materials.*;   import sandy.materials.attributes.*;   import sandy.primitive.*;    public class Example0041 extends Sprite {      private var scene:Scene3D;      private var camera:Camera3D;      private var tg:TransformGroup;      private var lightX = 0;      private var lightY = 0;      private var lightZ = 10;       public function Example0041() {          camera = new Camera3D( 300, 300 );         camera.z = -400;          var root:Group = createScene();          scene = new Scene3D( "scene", this, camera, root );         scene.light.setDirection(lightX, lightY, lightZ);          addEventListener( Event.ENTER_FRAME, enterFrameHandler );          stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);      }       private function createScene():Group {         var g:Group = new Group();         tg = new TransformGroup();          var materialAttr:MaterialAttributes = new MaterialAttributes(                           new LineAttributes( 0, 0x2111BB, 0 ),                           new LightAttributes( true, 0.1)                        );          var material:Material = new ColorMaterial( 0xFFCC33, 1, materialAttr );         material.lightingEnable = true;         var app:Appearance = new Appearance( material );          var materialAttr2:MaterialAttributes = new MaterialAttributes(                            new LineAttributes( 0, 0x2111BB, 0 ),                           new LightAttributes( true, 0.1)                        );          var material2:Material = new ColorMaterial( 0xCC0000, 1, materialAttr );         material2.lightingEnable = true;         var app2:Appearance = new Appearance( material2 );          var materialAttr3:MaterialAttributes = new MaterialAttributes(                           new LineAttributes( 0, 0x2111BB, 0 ),                           new LightAttributes( true, 0.1)                        );          var material3:Material = new ColorMaterial( 0x008AE6, 1, materialAttr );         material3.lightingEnable = true;         var app3:Appearance = new Appearance( material3 );          var table = new Box( "table", 10, 150, 200, PrimitiveMode.QUAD, 1 );         //table.enableBackFaceCulling = false;         table.useSingleContainer = false;         table.appearance = app;         table.rotateY = 90;         table.rotateX = 90;          var leg01:Cylinder = new Cylinder( "leg01", 5, 80 );         leg01.appearance = app;         leg01.x = -80;         leg01.y = -45;         leg01.z = 50;          var leg02:Cylinder = new Cylinder( "leg02", 5, 80 );         leg02.appearance = app;         leg02.x = 80;         leg02.y = -45;         leg02.z = 50;          var leg03:Cylinder = new Cylinder( "leg02", 5, 80 );         leg03.appearance = app;         leg03.x = -80;         leg03.y = -45;         leg03.z = -50;          var leg04:Cylinder = new Cylinder( "leg02", 5, 80 );         leg04.appearance = app;         leg04.x = 80;         leg04.y = -45;         leg04.z = -50;          var mySphere:Sphere = new Sphere( "theSphere", 20, 20, 8);         mySphere.useSingleContainer = true;         mySphere.appearance = app2;         mySphere.y = 25;         mySphere.x = -30;          var myBox:Box = new Box( "theBox", 60, 60, 60, PrimitiveMode.TRI, 3 );         myBox.useSingleContainer = true;         myBox.appearance = app3;         myBox.rotateY = 30;         myBox.y = 35;         myBox.x = 40;          tg.addChild(table);         tg.addChild(leg01);         tg.addChild(leg02);         tg.addChild(leg03);         tg.addChild(leg04);         tg.addChild(mySphere);         tg.addChild(myBox);          tg.rotateX = 5;          g.addChild( tg );          return g;      }       private function enterFrameHandler( event : Event ) : void {         scene.render();      }       private function keyPressed(event:KeyboardEvent):void {         switch(event.keyCode) {            case Keyboard.PAGE_DOWN:               scene.light.setPower(scene.light.getPower() - 5);               break;            case Keyboard.PAGE_UP:               scene.light.setPower(scene.light.getPower() + 5);               break;            case Keyboard.UP:               lightY+=10;               scene.light.setDirection(lightX, lightY, lightZ);               break;            case Keyboard.DOWN:               lightY-=10;               scene.light.setDirection(lightX, lightY, lightZ);               break;            case Keyboard.RIGHT:               lightX+=10;               scene.light.setDirection(lightX, lightY, lightZ);               break;            case Keyboard.LEFT:               lightX-=10;               scene.light.setDirection(lightX, lightY, lightZ);               break;         }      }   }}

 

 

让我们看看在代码里做了什么

 

X,Y,Z变量

因为要控制灯光的方向，所以我们在3D的世界里需要三个变量X，Y，Z，我们把它们高为成员变量。这样我们就可以通过键盘的方向键来控制它们的值了。

private var lightX = 0;
private var lightY = 0;
private var lightZ = 10;

 

设置灯光的位置

scene.light.setDirection(lightX, lightY, lightZ);

 

如你所见，你只需获取Scene3D对象的light属性然后调置它的值就可以了。

 

然后在createScene()方法里，我放入了很多对象来模拟一张台和一个球和一个圆环。这张台是一个Box和四个Cylinder（作为四条腿），还有那个球是一个Sphere对象。我将跳过这部份的代码说明，因为我想在之前的指南中，你能很容易理解这些。

 

创建输入控制器

现在让我们做最重要的东西就是放在控制函数：keyPressed(event:KeyboardEvent).中的代码：

case Keyboard.PAGE_DOWN:
   scene.light.setPower(scene.light.getPower() - 5);
   break;
case Keyboard.PAGE_UP:
   scene.light.setPower(scene.light.getPower() + 5);
   break; 
case Keyboard.UP:
   lightY+=10;
   scene.light.setDirection(lightX, lightY, lightZ);
   break;
case Keyboard.DOWN:
   lightY-=10;
   scene.light.setDirection(lightX, lightY, lightZ);
   break;
case Keyboard.RIGHT:
   lightX+=10;
   scene.light.setDirection(lightX, lightY, lightZ);
   break;
case Keyboard.LEFT:
   lightX-=10;
   scene.light.setDirection(lightX, lightY, lightZ);
   break;

 

使用pageUp和pageDown键可以控制灯光的强度，方向键可以控制灯光的方向。

 

下面让我们看看最终的效果：

http://www.flashsandy.org/_media/tutorials/3.0/example0041.swf

 

代码下载：example0041.rar