如何在Windows Phone 7 3D开发中使用纹理贴图
Windows Phone 7对3D的支持还是不错的，据说是用OpenGL/ES做的，使用起来倒是也有点那种感觉。本文就不讲XNA 4.0的游戏框架了，直接上一段代码，该代码使用VertexPositionColor渲染了一个三角形，程序运行一切正常。[*]+ expand sourceview plaincopy to clipboardprint?
[*]
运行结果如下：
http://images.51cto.com/files/uploadimg/20110316/1037080.gif
在确认了3D开发的这种代码结构以后，用VertexPositionTexture渲染同样的三角形，只是这次采用纹理贴图，代码如下：
[*]
[*]view plaincopy to clipboardprint?
[*]VertexPositionTexture[] trangleTexture;
[*]
[*]protected override void LoadContent()
[*]{
[*] spriteBatch = new SpriteBatch(GraphicsDevice);
[*]
[*] image = Content.Load<Texture2D>(@&quot;Images/Tulips&quot;);
[*] trangleTexture = new VertexPositionTexture[]{
[*] new VertexPositionTexture(new Vector3(0, 1, 0),new Vector2(0.5f,0) ),
[*] new VertexPositionTexture(new Vector3(1, -1, 0),new Vector2(1,1f) ),
[*] new VertexPositionTexture(new Vector3(-1,-1, 0),new Vector2(0,1f) )
[*] };
[*]
[*] vertexBuffer = new VertexBuffer(GraphicsDevice, typeof(VertexPositionTexture), trangleTexture.Length, BufferUsage.None);
[*] vertexBuffer.SetData<VertexPositionTexture>(trangleTexture);
[*]
[*] basicEffect = new BasicEffect(GraphicsDevice);
[*]
[*] GraphicsDevice.SetVertexBuffer(vertexBuffer);
[*]}
[*]
[*]protected override void Draw(GameTime gameTime)
[*]{
[*] GraphicsDevice.Clear(Color.CornflowerBlue);
[*]
[*] basicEffect.World = world;
[*] basicEffect.View = camera.view;
[*] basicEffect.Projection = camera.projection;
[*] basicEffect.Texture = image;
[*] basicEffect.TextureEnabled = true;
[*]
[*] foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes)
[*] {
[*] pass.Apply();
[*] GraphicsDevice.DrawUserPrimitives<VertexPositionTexture>(PrimitiveType.TriangleStrip, trangleTexture, 0, 1);
[*] }
[*] base.Draw(gameTime);
[*]}
啰嗦一句，在此代码中VertexPositionTexture的第二个Vetex2代表的是UV坐标，对应的含义是（0，0）点对应了纹理图片的左上角，（1，1）点对应了纹理图片的右下角。
上述代码在运行的时候会在VS2010的输出窗口中显示：
A first chance exception of type 'System.NotSupportedException' occurred in Microsoft.Xna.Framework.Graphics.dll
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in Microsoft.Xna.Framework.dll 同时模拟器里的程序直接退出，看不到结果。原因是什么呢？疑惑并仔细检视代码中&hellip;&hellip;
与前一个彩色三角形对比，顶点顺序没变，摄像机位置没变，投影矩阵没变，按说是不可能出现这种问题的，而且程序直接崩了，没有信息抛出，真是很郁闷。
经过不断的试错，在宣布放弃之前，忽然想起来关于纹理方面的一个注意事项。有过3D开发经验的朋友都知道，纹理是要求符合2的整数次方对齐的，而我所加载的来自于外部任意图片的纹理不符合这一要求，所以程序挂了。
又查了一些资料，找到了准确的原因。原来是Windows Phone 7 的XNA中默认的纹理寻址模式使用了Wrap，造成了与GPU的不兼容，如果改成Clamp就好了。
看来在这个地方微软得要有文档说明才好，否则还真是难找问题所在。修改后的代码如下：
[*]view plaincopy to clipboardprint?
[*]protected override void LoadContent()
[*]{
[*] // Create a new SpriteBatch, which can be used to draw textures.
[*] spriteBatch = new SpriteBatch(GraphicsDevice);
[*]
[*] image = Content.Load<Texture2D>(@&quot;Images/Tulips&quot;);
[*]
[*] trangleTexture = new VertexPositionTexture[]{
[*] new VertexPositionTexture(new Vector3(0, 1, 0),new Vector2(0.5f,0) ),
[*] new VertexPositionTexture(new Vector3(1, -1, 0),new Vector2(1,1f) ),
[*] new VertexPositionTexture(new Vector3(-1,-1, 0),new Vector2(0,1f) )
[*] };
[*]
[*] vertexBuffer = new VertexBuffer(GraphicsDevice, typeof(VertexPositionTexture), trangleTexture.Length, BufferUsage.None);
[*] vertexBuffer.SetData<VertexPositionTexture>(trangleTexture);
[*]
[*] basicEffect = new BasicEffect(GraphicsDevice);
[*]
[*] GraphicsDevice.SetVertexBuffer(vertexBuffer);
[*] GraphicsDevice.SamplerStates = SamplerState.PointClamp;
[*]}
[*]
最终的模拟器结果是：
http://images.51cto.com/files/uploadimg/20110316/1037081.gif
不管怎么说，Windows Phone 7的XNA游戏开发框架以及3D方面的开发接口还是很出色的，顶一下微软，并希望这个平台能尽快发展起来。
附Camera的代码：
[*]view plaincopy to clipboardprint?
[*]using System;
[*]using System.Collections.Generic;
[*]using System.Linq;
[*]using Microsoft.Xna.Framework;
[*]using Microsoft.Xna.Framework.Audio;
[*]using Microsoft.Xna.Framework.Content;
[*]using Microsoft.Xna.Framework.GamerServices;
[*]using Microsoft.Xna.Framework.Graphics;
[*]using Microsoft.Xna.Framework.Input;
[*]using Microsoft.Xna.Framework.Media;
[*]
[*]
[*]namespace WindowsPhoneGame1
[*]{
[*] public class Camera : Microsoft.Xna.Framework.GameComponent
[*] {
[*] public Matrix view{get;protected set;}
[*] public Matrix projection { get; protected set; }
[*]
[*] public Camera(Game game,Vector3 pos,Vector3 target,Vector3 up)
[*] : base(game)
[*] {
[*] view = Matrix.CreateLookAt(pos, target, up);
[*] projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, (float)game.Window.ClientBounds.Width / (float)game.Window.ClientBounds.Height, 1, 100);
[*] }
[*]
[*] public override void Initialize()
[*] {
[*] base.Initialize();
[*] }
[*]
[*] public override void Update(GameTime gameTime)
[*] {
[*] base.Update(gameTime);
[*] }
[*] }
[*]}
[*]
本文转自http://blog.csdn.net/caowenbin
【编辑推荐】
[*]Windows Phone 7中用好Silverlight开发利器
[*]Windows Phone 7的地图控件
[*]Windows Phone 7的枢轴控件
[*]Windows Phone 7的全景视图控件
[*]使用独立存储开发Windows Phone 7应用程序
<DIV align=right>【责任编辑：立方 TEL：（010）68476606】
页:
[1]