Flash3D学习计划（三）——学习VB，IB相关，理解三角形顶点顺序；在屏幕上显示2D矩形，并实现缩放，平移，旋转

VB：顶点缓冲

IB: 顶点索引缓冲

三角形的顶点顺序决定了三角形是顺时针还是逆时针，从而决定了三角形在背面剔除的过程中是否会被剔除掉。

相关理论知识可以在前面的文章中找到更多的说明。

实现效果

sfw下载

主要代码

  1 package

  2 {

  3     import com.adobe.utils.AGALMiniAssembler;

  4     import com.adobe.utils.PerspectiveMatrix3D;

  5     

  6     import flash.display.Sprite;

  7     import flash.display.Stage3D;

  8     import flash.display3D.Context3D;

  9     import flash.display3D.Context3DProgramType;

 10     import flash.display3D.Context3DVertexBufferFormat;

 11     import flash.display3D.IndexBuffer3D;

 12     import flash.display3D.Program3D;

 13     import flash.display3D.VertexBuffer3D;

 14     import flash.events.Event;

 15     import flash.geom.Matrix3D;

 16     import flash.geom.Vector3D;

 17     

 18     /**

 19      * @author smartqi

 20      * @E-mail: 

 21      * 创建时间：2013-6-29 上午9:36:36

 22      * 

 23      */

 24     public class RectangleTest extends Sprite

 25     {

 26         

 27         private var context:Context3D;

 28         private var vertexBuff:VertexBuffer3D;

 29         private var indexBuff:IndexBuffer3D;

 30         private var vertexData:Vector.<Number>;

 31         private var indexData:Vector.<uint>;

 32         private var shaderProgram:Program3D;

 33         private var perspectiveMatrix:PerspectiveMatrix3D;

 34         private var i:int;

 35         private var sign:int = 1;

 36         private const angleGap:Number = 20;

 37         private var angle:Number = 0;

 38         private var modelMatrix:Matrix3D;

 39         private var viewMatrix:Matrix3D;

 40         private var finalMatrix:Matrix3D;

 41         

 42         

 43         public function RectangleTest()

 44         {

 45             var stage3d:Stage3D = stage.stage3Ds[0];

 46             stage3d.addEventListener(Event.CONTEXT3D_CREATE,onContextCreate);

 47             stage3d.requestContext3D();

 48         }

 49         

 50         private function onContextCreate(e:Event):void{

 51             context = (e.target as Stage3D).context3D;

 52             if(context == null) return;

 53             context.enableErrorChecking = true; //允许进行错误检测，release版本应设置

 54             context.configureBackBuffer(500,500,0); //设置显示区域的大小

 55             setupVertexBuff(); //设置顶点缓冲

 56             setupShaderProgram(); //设置shander

 57             setupPerspectiveMatrix(); //设置投影矩阵

 58             initMatrix();

 59             addEventListener(Event.ENTER_FRAME,onEnterFrame);

 60         }

 61         

 62         private function setupVertexBuff():void{

 63             vertexData = Vector.<Number>([

 64                 // x    y     z     r     g     b

 65                 40,        40,        -40,    1,    0,    0,

 66                 40,        -40,    -40,    0,    1,    0,

 67                 -40,    -40,    -40,    0,    0,    1,

 68                 -40,    40,        -40,    1,    1,    1,

 69             ]);

 70             

 71             indexData = Vector.<uint>([0,1,2,0,2,3]);

 72             vertexBuff = context.createVertexBuffer(4,vertexData.length/4);

 73             vertexBuff.uploadFromVector(vertexData,0,4);

 74             indexBuff = context.createIndexBuffer(6);

 75             indexBuff.uploadFromVector(indexData,0,6);

 76             context.setVertexBufferAt(0,vertexBuff,0,Context3DVertexBufferFormat.FLOAT_3);

 77             context.setVertexBufferAt(1,vertexBuff,3,Context3DVertexBufferFormat.FLOAT_3);

 78         }

 79         

 80         private function setupShaderProgram():void{

 81             var vertexProgram:AGALMiniAssembler =  new AGALMiniAssembler();

 82             vertexProgram.assemble(Context3DProgramType.VERTEX,

 83                 "m44 op,va0,vc0\n" +

 84                 "mov v1,va1\n");

 85             var fragmentProgram:AGALMiniAssembler = new AGALMiniAssembler();

 86             fragmentProgram.assemble(Context3DProgramType.FRAGMENT,

 87                 "mov oc,v1");

 88             shaderProgram = context.createProgram();

 89             shaderProgram.upload(vertexProgram.agalcode,fragmentProgram.agalcode);

 90             context.setProgram(shaderProgram);

 91         }

 92         

 93         private function setupPerspectiveMatrix():void{

 94             perspectiveMatrix = new PerspectiveMatrix3D();

 95             perspectiveMatrix.perspectiveFieldOfViewRH(Math.PI*90/180,1,1,1000);  //注意这里的角度使用的是弧度

 96         }

 97         

 98         private function initMatrix():void{

 99             modelMatrix = new Matrix3D();

100             viewMatrix = new Matrix3D();

101             finalMatrix = new Matrix3D();

102         }

103         

104         private function onEnterFrame(e:Event):void{

105             context.clear(0,0,0);

106             angle += angleGap;

107             modelMatrix.identity();

108             modelMatrix.prependRotation(angle,Vector3D.Z_AXIS);  //绕着Z轴旋转物体，注意这里的角度使用的是角度

109             if(i>30){

110                 sign = -1;

111             }

112             if(i<0){

113                 sign = 1;

114             }

115             i += sign;

116             viewMatrix.identity();

117             viewMatrix.prependTranslation(0,0,-30 + i); //将相机向后移，使物体看起来变小了,将相机向前移，使物体看起来变大

118             finalMatrix.identity();

119             finalMatrix.append(modelMatrix);

120             finalMatrix.append(viewMatrix);

121             finalMatrix.append(perspectiveMatrix);

122             context.setProgramConstantsFromMatrix(Context3DProgramType.VERTEX,0,finalMatrix,true); //上传最终的顶点转换矩阵，注意这里最后一个参数为true

123             context.drawTriangles(indexBuff,0,2);

124             context.present();

125         }

126     }

127 }