unity 文件流读取图片与www读取图片的区别介绍

void LoadByIO() {
        float time = Time.time;
        FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);
        fs.Seek(0, SeekOrigin.Begin);
        byte[] bytes = new byte[fs.Length];
        fs.Read(bytes, 0, (int)fs.Length);
        fs.Close();
        fs.Dispose();
        fs = null;
 
        Texture2D t = new Texture2D(1,1);
        t.LoadImage(bytes);
        img.texture = t;
        Debug.Log("IO读取图片用时：" + (Time.time-time));
    }

IEnumerator LoadByWWW() {
        float time = Time.time;
        WWW w = new WWW("file://" + path);
        yield return w;
        if (string.IsNullOrEmpty(w.error) == false)
        {
            Debug.Log("error");
        }
        else {
            img1.texture = w.texture;
        }
        Debug.Log("www读取图片用时:" + (Time.time - time));
    }

Texture2D imgTexture = Resources.Load("background_one") as Texture2D;
Sprite sprite = Sprite.Create(imgTexture, new Rect(0, 0, imgTexture.width, imgTexture.height), new Vector2(0.5f, 0.5f));
Image image = GetComponent<Image>();
image.sprite = sprite;

//Resources.Load加载图片默认的是Texture2D类型，加了typeof(Sprite)后，就是加载为sprite类型
//然后又转换为object，所以要再用as Sprite转换为Sprite，
//如果不加typeof(Sprite),它就是Texture2D转换为object，就不成强制转换为Sprite
Image image = GetComponent<Image>();
image.sprite = Resources.Load("background_one", typeof(Sprite)) as Sprite;

    public Sprite play;
    public Sprite pause;
    Image image = GetComponent<Image>();
    image.sprite = play;
    image.sprite = pause;

//用www方式读取
string path = @"E:\UnityProject\ARVR\Workspace\Test2\Assets\texture\background_one.png";
WWW www = new WWW(path);
Texture2D texture = www.texture;
Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
Image image = GetComponent<Image>();
image.sprite = sprite;

//创建文件读取流
string path = @"E:\UnityProject\ARVR\Workspace\Test2\Assets\texture\background_one.png";
FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read);
fileStream.Seek(0, SeekOrigin.Begin);
byte[] bye = new byte[fileStream.Length];
fileStream.Read(bye, 0, bye.Length);
fileStream.Close();
//创建texture
Texture2D texture2D = new Texture2D(240, 144);
texture2D.LoadImage(bye);
//创建sprite
Sprite sprite = Sprite.Create(texture2D, new Rect(0, 0, texture2D.width, texture2D.height), new Vector2(0.5f, 0.5f));
Image image = GetComponent<Image>();
image.sprite = sprite;