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。
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运行结果如下:
![Windows Phone 7 3D开发中使用纹理贴图_第1张图片](http://img.e-com-net.com/image/info8/c8308d9d7ee04fbfad259a4c7c33ce0e.jpg)
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:
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. VertexPositionTexture[] trangleTexture;
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.
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.
protected
override
void
LoadContent()
6
. {
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. spriteBatch
=
new
SpriteBatch(GraphicsDevice);
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.
9
. image
=
Content.Load
<
Texture2D
>
(@
"
Images/Tulips
"
);
10
. trangleTexture
=
new
VertexPositionTexture[]{
11
.
new
VertexPositionTexture(
new
Vector3(
0
,
1
,
0
),
new
Vector2(
0.5f
,
0
) ),
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.
new
VertexPositionTexture(
new
Vector3(
1
,
-
1
,
0
),
new
Vector2(
1
,1f) ),
13
.
new
VertexPositionTexture(
new
Vector3(
-
1
,
-
1
,
0
),
new
Vector2(
0
,1f) )
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. };
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.
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. vertexBuffer
=
new
VertexBuffer(GraphicsDevice, typeof(VertexPositionTexture), trangleTexture.Length, BufferUsage.None);
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. vertexBuffer.SetData
<
VertexPositionTexture
>
(trangleTexture);
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.
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. basicEffect
=
new
BasicEffect(GraphicsDevice);
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.
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. GraphicsDevice.SetVertexBuffer(vertexBuffer);
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. }
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.
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.
protected
override
void
Draw(GameTime gameTime)
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. {
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. GraphicsDevice.Clear(Color.CornflowerBlue);
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.
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. basicEffect.World
=
world;
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. basicEffect.View
=
camera.view;
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. basicEffect.Projection
=
camera.projection;
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. basicEffect.Texture
=
image;
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. basicEffect.TextureEnabled
=
true
;
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.
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. foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes)
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. {
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. pass.Apply();
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. GraphicsDevice.DrawUserPrimitives
<
VertexPositionTexture
>
(PrimitiveType.TriangleStrip, trangleTexture,
0
,
1
);
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. }
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. base.Draw(gameTime);
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. }
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……
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:
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?
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.
protected
override
void
LoadContent()
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. {
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.
//
Create a new SpriteBatch, which can be used to draw textures.
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. spriteBatch
=
new
SpriteBatch(GraphicsDevice);
6
.
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. image
=
Content.Load
<
Texture2D
>
(@
"
Images/Tulips
"
);
8
.
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. trangleTexture
=
new
VertexPositionTexture[]{
10
.
new
VertexPositionTexture(
new
Vector3(
0
,
1
,
0
),
new
Vector2(
0.5f
,
0
) ),
11
.
new
VertexPositionTexture(
new
Vector3(
1
,
-
1
,
0
),
new
Vector2(
1
,1f) ),
12
.
new
VertexPositionTexture(
new
Vector3(
-
1
,
-
1
,
0
),
new
Vector2(
0
,1f) )
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. };
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.
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. vertexBuffer
=
new
VertexBuffer(GraphicsDevice, typeof(VertexPositionTexture), trangleTexture.Length, BufferUsage.None);
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. vertexBuffer.SetData
<
VertexPositionTexture
>
(trangleTexture);
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.
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. basicEffect
=
new
BasicEffect(GraphicsDevice);
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.
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. GraphicsDevice.SetVertexBuffer(vertexBuffer);
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. GraphicsDevice.SamplerStates[
0
]
=
SamplerState.PointClamp;
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. }
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.
最终的模拟器结果是:
![Windows Phone 7 3D开发中使用纹理贴图_第2张图片](http://img.e-com-net.com/image/info8/1d1a50fc76704c3eaa41ce1b02f3f034.jpg)
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:
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. using System;
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. using System.Collections.Generic;
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. using System.Linq;
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. using Microsoft.Xna.Framework;
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. using Microsoft.Xna.Framework.Audio;
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. using Microsoft.Xna.Framework.Content;
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. using Microsoft.Xna.Framework.GamerServices;
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. using Microsoft.Xna.Framework.Graphics;
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. using Microsoft.Xna.Framework.Input;
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. using Microsoft.Xna.Framework.Media;
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.
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.
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. namespace WindowsPhoneGame1
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. {
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.
public
class
Camera : Microsoft.Xna.Framework.GameComponent
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. {
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.
public
Matrix view{get;
protected
set;}
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.
public
Matrix projection { get;
protected
set; }
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.
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.
public
Camera(Game game,Vector3 pos,Vector3 target,Vector3 up)
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. : base(game)
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. {
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. view
=
Matrix.CreateLookAt(pos, target, up);
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. projection
=
Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, (
float
)game.Window.ClientBounds.Width
/
(
float
)game.Window.ClientBounds.Height,
1
,
100
);
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. }
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.
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.
public
override
void
Initialize()
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. {
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. base.Initialize();
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. }
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.
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.
public
override
void
Update(GameTime gameTime)
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. {
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. base.Update(gameTime);
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. }
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. }
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. }
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.