最近碰到一個功能，需要將一張大圖切割成若干個小圖在拼成大圖。

首先定義一些基礎(chǔ)變量

    //小圖的寬和高
    public int m_iMinWidth;
    public int m_iMinHeight;
    //一行有多少個小圖
    public int m_iMinPicRowCount;
    //一列有多少個小圖
    public int m_iMinPicColumnCount;
    //需要切割的大圖
    public Texture2D m_texPlayer;
    //小圖數(shù)組
    private Texture2D[,] m_texPlayers;

初始化一些變量

    //初始化行數(shù)列數(shù)
    m_iMinPicRowCount = 22;
    m_iMinPicColumnCount = 12;
    //根據(jù)行數(shù)和列數(shù)構(gòu)造儲存小圖的數(shù)組
    m_texPlayers = new Texture2D[m_iMinPicRowCount, m_iMinPicRowCount];

核心方法 分割大圖，核心思想就是在大圖上去像素點賦值給小圖

    //切圖
    void DePackTexture(int i, int j)
    {
        //通過大圖寬高計算出每次切圖的大小
        m_iMinHeight = m_texPlayer.height / m_iMinPicColumnCount;
        m_iMinWidth = m_texPlayer.width / m_iMinPicRowCount;
        
        int cur_x = i * m_iMinWidth;
        int cur_y = j * m_iMinHeight;
        Texture2D newTexture = new Texture2D(m_iMinWidth, m_iMinHeight);
        for (int m = cur_y; m < cur_y + m_iMinHeight; m++)
        {
            for (int n = cur_x; n < cur_x + m_iMinWidth; n++)
            {
                //核心 通過從大圖拿到的像素點賦值給小圖
                newTexture.SetPixel(n - cur_x, m - cur_y, m_texPlayer.GetPixel(n, m));
            }
        }
        //Apply一下 更新貼圖
        newTexture.Apply();
        //儲存到數(shù)組
        m_texPlayers[i, j] = newTexture;

    }

有時候會碰到說大圖不能讀的情況，這是Unity為了節(jié)省性能默認(rèn)的為不可讀了，可以在設(shè)置中更改，也可以使用下面這個方法：

    private Texture2D duplicateTexture(Texture2D source)
    {
        RenderTexture renderTex = RenderTexture.GetTemporary(
                    source.width,
                    source.height,
                    0,
                    RenderTextureFormat.Default,
                    RenderTextureReadWrite.Linear);

        Graphics.Blit(source, renderTex);
        RenderTexture previous = RenderTexture.active;
        RenderTexture.active = renderTex;
        Texture2D readableText = new Texture2D(source.width, source.height);
        readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
        readableText.Apply();
        RenderTexture.active = previous;
        RenderTexture.ReleaseTemporary(renderTex);
        return readableText;
    }

調(diào)用下這個方法

m_texPlayer = duplicateTexture(m_texPlayer);

根據(jù)行列數(shù)分割大圖

  //切割圖片
  for (int i = 0; i < m_iMinPicRowCount; i++)
       {
            for (int j = 0; j < m_iMinPicColumnCount; j++)
            {
                DePackTexture(i, j);
            }
        }

最后創(chuàng)建下Quad看下效果

    //創(chuàng)建Quad
    void CreatQuad()
    {
        GameObject go = Resources.Load<GameObject>("Quad");
        for (int i = 0; i < m_iMinPicRowCount; i++)
        {
            for (int j = 0; j < m_iMinPicColumnCount; j++)
            {
                GameObject g = Instantiate(go, new Vector3(i, j, 0), Quaternion.identity);
                //將材質(zhì)賦給對應(yīng)的Quad
                g.gameObject.GetComponent<MeshRenderer>().material.mainTexture = m_texPlayers[i, j];
            }
        }
    }

效果展示

image.png

但是這樣會有一個問題，就是圖片之間有很明顯的縫隙感，這是由于創(chuàng)建的Texture2D大小并不能完美貼合所創(chuàng)建出來的Quad。
所以我們需要修改wrapMode，代碼如下：

newTexture.wrapMode = TextureWrapMode.Clamp;

運行效果如下：

image.png

是不是就很完美了。