UNITY3D 从网络获取图片 并 截取图片一部分显示

using UnityEngine;
using System.Collections;

public class GetWebImage : MonoBehaviour {

string url = "http://img.hb.aicdn.com/240136a8caf6ae05d38f2f57d596aec10c44d1ff112df-4XaoQJ_fw580";
private Material material;

IEnumerator Start () {
WWW www = new WWW(url);
yield return www;
material = new Material(Shader.Find("Unlit/Transparent Colored"));
material.mainTexture = www.texture;

Split(4,4);
}

/// <summary>
/// 分割图片
/// </summary>
void Split(int width,int height) {

float x = -400;
float y = -200;

for (int i = 0; i < width; i++ )
{
for (int n = 0; n < height; n++)
{
GameObject obj = CreateObj();
SetUv(obj.GetComponent<MeshFilter>().mesh);
obj.transform.localScale = new Vector3(material.mainTexture.width/width,material.mainTexture.height/height,1);

x += 100;
obj.transform.parent = transform.parent;
obj.transform.localPosition = new Vector3(x,y,1);
}
x = -400;
y += 200;
}

}

/// <summary>
/// 创建对象
/// </summary>
private GameObject CreateObj() {
GameObject obj = new GameObject();
MeshFilter meshFilter       =   obj.AddComponent<MeshFilter>();
MeshRenderer meshRenderer   =   obj.AddComponent<MeshRenderer>();
meshRenderer.material = material;
return obj;
}

/// <summary>
/// 贴图
/// </summary>
void SetUv(Mesh mesh) {
//定点坐标
Vector3[] vertices = new Vector3[4];
vertices[0] = new Vector3(0, 0, 0);
vertices[1] = new Vector3(0, 1, 0);
vertices[2] = new Vector3(1, 1, 0);
vertices[3] = new Vector3(1, 0, 0);

mesh.vertices = vertices;

//三角形连线
int[] triangles = new int[6];
triangles[0] = 0;
triangles[1] = 1;
triangles[2] = 3;

triangles[3] = 1;
triangles[4] = 3;
triangles[5] = 2;

mesh.triangles = triangles;

//设置uv坐标
Vector2 uvPostion0 = new Vector2(0, 0);
Vector2 uvPostion1 = new Vector2(0, 0.5f);
Vector2 uvPostion2 = new Vector2(0.5f, 0.5f);
Vector2 uvPostion3 = new Vector2(0.5f, 0);

mesh.uv = new Vector2[] { uvPostion0, uvPostion1, uvPostion2, uvPostion3 };
}

}