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Stage3D_Game_Programming:渲染3D模型

OBJ是文件，先来解释下OBJ文件。随便找一个OBJ文件，用文本查看：

# Max2Obj Version 4.0 Mar 10th, 2001
#
# object (null) to come ...
#
v -0.257 0.191 0.423
v -0.115 0.29 -0.068
v -0.237 0 -0.074
v -0.237 0.071 0.646
...
# 82 vertices
vt 0.623 0.227 0
vt 0.615 0.53 0
vt 0.895 0.555 0
vt 0.825 0.246 0
vt 0.647 0.847 0
...
# 39 texture vertices
f 1/1 2/2 3/3
f 3/3 4/4 1/1
f 2/2 5/5 6/6
f 6/6 3/3 2/2
...
# 142 faces

v:是模型的顶点信息 vt:是贴图的UV坐标 f:是定义面的顶点索引和顶点对应的UV坐标索引清楚了OBJ文件里各种数据所代表的信息，接下来就是如何把数据传递给显卡渲染。那么我们需要一个解析OBJ文件的类(代码比较简单，注释就省了)

 



package com.parser
{
    import flash.utils.ByteArray;
 
  
    public class OBJParser
    {
        private var _lines:Array;
        private const LINE_FEED:String = String.fromCharCode(10);
        private const SPACE:String = String.fromCharCode(32);
        private var _scale:Number;
        public function OBJParser(objfile:ByteArray,scale:Number = 1)
        {
            _scale = scale;
            if(objfile)
            {
                var lineStr:String = parserToStr(objfile);
                _lines = lineStr.split(LINE_FEED);
                var loop:uint = _lines.length;
                for(var i:uint = 0; i < loop; i++)
                {
                    parseLine(_lines[i]);
                }
            }   
        }
 
        private const VERTEX:String = 'v';
        private const UV:String = 'vt';
        private const INDEX_DATA:String = 'f';
        private function parseLine(lineStr:String):void
        {
            var data:Array = lineStr.split(SPACE);
            if(!data.length)return;
            var key:String = data[0];
            var parseData:Array = data.slice(1);
            switch(key)
            {
                case VERTEX:
                    parseVertex(parseData);
                    break;
                case UV:
                    parseUV(parseData);
                    break;
                case INDEX_DATA:
                    parseIndexData(parseData);
                    break;
            }
        }
 
        private var _vertices:Vector.<Number> = new Vector.<Number>();
        private function parseVertex(data:Array):void
        {
            if(data[0] == '' || data[0] == " ")
            {
                data = data.slice(1);
            }
            var loop:uint = data.length;
            for(var i:uint = 0; i < loop; i++)
            {
                var value:Number = Number(data[i]);
                _vertices.push(value*_scale);
            }
        }
 
        private var _uvs:Vector.<Number> = new Vector.<Number>();
        private function parseUV(data:Array):void
        {
            if(data[0] == '' || data[0] == " ")
            {
                data = data.slice(1);
            }
            var loop:uint = 2;
            for(var i:uint = 0; i < loop; i++)
            {
                var value:Number = Number(data[i]);
                _uvs.push(value*_scale);
            }
        }
 
        private const SLASH:String = "/";
        private var _indexData:Vector.<uint> = new Vector.<uint>();
        private var _vertexsData:Vector.<Number> = new Vector.<Number>();
        private var _uvData:Vector.<Number> = new Vector.<Number>();
        private var _faceIndex:uint;
        private function parseIndexData(data:Array):void
        {
            var index:uint = 0;
            while((data[index] == '') || (data[index] == ' '))index++;
            var loop:uint = index+3;
 
            var vertexIndex:int;
            var uvIndex:int;
            var normalIndex:int;
            for(var i:uint = index; i < loop; i++)
            {
                var triplet:String = data[i];
                var subdata:Array = triplet.split(SLASH);
                vertexIndex = int(subdata[0]) - 1;
                uvIndex     = int(subdata[1]) - 1;
 
                if(vertexIndex < 0) vertexIndex = 0;
                if(uvIndex < 0) uvIndex = 0;
 
                index = 3*vertexIndex;
                _vertexsData.push(_vertices[index + 0], 
                _vertices[index + 1], _vertices[index + 2]);
 
                index = 2*uvIndex;
                _uvData.push(1-_uvs[index+0],1-_uvs[index+1]);
            }
            _indexData.push(_faceIndex+0,_faceIndex+1,_faceIndex+2);
            _faceIndex += 3;
        }
 
        private function parserToStr(objFileByteArray:ByteArray):String
        {
            return objFileByteArray.readUTFBytes(objFileByteArray.bytesAvailable);
        }
 
        /**
         * 顶点数据 
         * @return 
         * 
         */    
        public function get vertexsData():Vector.<Number>
        {
            return _vertexsData;
        }
 
        /**
         * UV数据 
         * @return 
         * 
         */    
        public function get uvData():Vector.<Number>
        {
            return _uvData;
        }
 
        /**
         * 索引数据 
         * @return 
         * 
         */    
        public function get indexData():Vector.<uint>
        {
            return _indexData;
        }
 
    }
}

有了顶点信息，uv信息和面的索引信息接下来就可以把这货渲染出来了。

 



package
{
    import com.adobe.utils.AGALMiniAssembler;
    import com.adobe.utils.PerspectiveMatrix3D;
    import com.parser.OBJParser;
 
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.Sprite;
    import flash.display.Stage3D;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.display3D.Context3D;
    import flash.display3D.Context3DProgramType;
    import flash.display3D.Context3DTextureFormat;
    import flash.display3D.Context3DVertexBufferFormat;
    import flash.display3D.IndexBuffer3D;
    import flash.display3D.Program3D;
    import flash.display3D.VertexBuffer3D;
    import flash.display3D.textures.Texture;
    import flash.events.Event;
    import flash.geom.Matrix;
    import flash.geom.Matrix3D;
    import flash.geom.Vector3D;
    import flash.utils.ByteArray;
 
    [SWF(width='800',height='600',backgroundColor='0x333333',frameRate="60")]
   
    public class GameTest extends Sprite
    {
        [Embed (source = "art/spaceship.obj", 
        mimeType = "application/octet-stream")] 
        private var objData:Class;
 
        [Embed (source = "art/spaceship_texture.jpg")] 
        private var TextureBitmap:Class;
        private var textureData:Bitmap = new TextureBitmap();
 
        private var _stage3D:Stage3D;
        private var _context3D:Context3D;
        private const sw:uint = 700;
        private const sh:uint = 500;
 
        private var _objParser:OBJParser;
        //顶点缓冲 存储顶点信息
        private var _vertexBuffer:VertexBuffer3D;
        //顶点缓冲 存储UV信息
        private var _uvBuffer:VertexBuffer3D;
        //顶点索引
        private var _indexBuffer:IndexBuffer3D;
        private var _texture:Texture;
        private var _textureSize:uint = 512;
        private var _projectionmatrix:PerspectiveMatrix3D;
        private var _viewmatrix:Matrix3D;
        private var _modelmatrix:Matrix3D = new Matrix3D();
        private var _modelViewProjection:Matrix3D = new Matrix3D();
 
        private var _vertexShaderAssembler:AGALMiniAssembler;
        private var _fragmentAssembler:AGALMiniAssembler;
        private var _program:Program3D;
 
        public function GameTest()
        {
            if(this.stage)
            {
                init();
            }else
            {
                addEventListener(Event.ADDED_TO_STAGE,init);
            }
        }
 
        private function init(e:Event = null):void
        {
            if(hasEventListener(Event.ADDED_TO_STAGE))removeEventListener(Event.ADDED_TO_STAGE,init);
            this.stage.scaleMode = StageScaleMode.NO_SCALE;
            this.stage.align = StageAlign.TOP_LEFT;
            initStage3D();
        }
 
        private function initStage3D():void
        {
            _stage3D = this.stage.stage3Ds[0];
            if(_stage3D)
            {
                _stage3D.addEventListener(Event.CONTEXT3D_CREATE,onContext3DCreate);
                _stage3D.requestContext3D();
            }
        }
 
        private function onContext3DCreate(e:Event):void
        {
            _context3D = _stage3D.context3D;
            if(_context3D == null)
            {
                throw new Error("无法创建Context3D");
                return;
            }
 
            _stage3D.x = (this.stage.stageWidth - sw)/2;
            _stage3D.y = (this.stage.stageHeight - sh)/2;
 
            _context3D.configureBackBuffer(sw,sh,1);
            _context3D.clear(205,205,205);
            _context3D.enableErrorChecking = true;
            initData();
            initShader();
            this.stage.addEventListener(Event.ENTER_FRAME,onEnterFrame);
        }
 
        private function initData():void
        {
            var objdata:ByteArray = new objData() as ByteArray;
            _objParser = new OBJParser(objdata);
 
            var vertexCont:uint = _objParser.vertexsData.length/3;
            _vertexBuffer = _context3D.createVertexBuffer(vertexCont,3);
            _vertexBuffer.uploadFromVector(_objParser.vertexsData,0,vertexCont);
 
            var uvCont:uint = _objParser.uvData.length/2;
            _uvBuffer = _context3D.createVertexBuffer(uvCont,2);
            _uvBuffer.uploadFromVector(_objParser.uvData,0,uvCont);
 
            _context3D.setVertexBufferAt(0,_vertexBuffer,0,Context3DVertexBufferFormat.FLOAT_3);
            _context3D.setVertexBufferAt(1,_uvBuffer,0,Context3DVertexBufferFormat.FLOAT_2);
 
            var indexData:Vector.<uint> = _objParser.indexData;
            _indexBuffer = _context3D.createIndexBuffer(indexData.length);
            _indexBuffer.uploadFromVector(indexData,0,indexData.length);
 
            _texture = _context3D.createTexture(_textureSize,_textureSize,Context3DTextureFormat.BGRA,false);
            uploadTextureWithMipmaps(_texture,textureData.bitmapData);
 
            _projectionmatrix = new PerspectiveMatrix3D();
            _projectionmatrix.identity();
            // 45 degrees FOV, 640/480 aspect ratio, 0.1=near, 100=far
            _projectionmatrix.perspectiveFieldOfViewRH(
                45.0, sw / sh, 0.01, 100.0);
 
            _viewmatrix = new Matrix3D();
            // camera Matrix3D
            _viewmatrix.identity();
            // 移动镜头到(0,0,0)
            _viewmatrix.appendTranslation(0,0,0);
        }
 
        private function initShader():void
        {
            _vertexShaderAssembler = new AGALMiniAssembler();
            _vertexShaderAssembler.assemble(Context3DProgramType.VERTEX,
                "m44 op, va0, vc0
" +
                "mov v0, va0
" +
                "mov v1, va1
");
 
            _fragmentAssembler= new AGALMiniAssembler();
            _fragmentAssembler..assemble
                ( 
                    Context3DProgramType.FRAGMENT,  
                    "tex ft0, v1, fs0 <2d,linear,repeat,miplinear>
"+
                    "mov oc, ft0
"
                );
 
            _program = _context3D.createProgram();
            _program.upload(_vertexShaderAssembler.agalcode,_fragmentAssembler.agalcode);
            _context3D.setTextureAt(0,_texture);            
            _context3D.setProgram(_program);
        }
 
        private var _t:Number = 0;
        private function onEnterFrame(e:Event):void
        {
            _context3D.clear(0,0,0,.7); 
            _t += 2.0;
            _modelmatrix.identity();
            //旋转模型
            _modelmatrix.appendRotation(_t*1.0, Vector3D.Y_AXIS);
            _modelmatrix.appendRotation(_t*-0.2, Vector3D.X_AXIS);
            _modelmatrix.appendRotation(_t*0.3, Vector3D.Y_AXIS);
            _modelmatrix.appendTranslation(-0.4, 0, -5);
 
            _modelViewProjection.identity();
            _modelViewProjection.append(_modelmatrix);
            _modelViewProjection.append(_viewmatrix);
            _modelViewProjection.append(_projectionmatrix);
 
            _context3D.setProgramConstantsFromMatrix(Context3DProgramType.VERTEX, 0, _modelViewProjection, true );
            //绘制模型
            _context3D.drawTriangles(_indexBuffer, 0, _objParser.indexData.length/3);
            //呈现至屏幕
            _context3D.present();
        }
 
        /**
         * Mipmap 
         * @param dest
         * @param src
         * 
         */    
        private function uploadTextureWithMipmaps(dest:Texture, src:BitmapData):void
        {
            var ws:int = src.width;
            var hs:int = src.height;
            var level:int = 0;
            var tmp:BitmapData;
            var transform:Matrix = new Matrix();
 
            tmp = new BitmapData(src.width, src.height, true, 0);
 
            while ( ws >= 1 && hs >= 1 )
            { 
                tmp.draw(src, transform, null, null, null, true); 
                dest.uploadFromBitmapData(tmp, level);
                transform.scale(0.5, 0.5);
                level++;
                ws >>= 1;
                hs >>= 1;
                if (hs && ws) 
                {
                    tmp.dispose();
                    tmp = new BitmapData(ws, hs, true, 0x00000000);
                }
            }
            tmp.dispose();
        }
 
    }
}

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原文地址：https://www.cnblogs.com/ch06src/p/3430964.html