unity 分割大图成若干个小图

2019-07-25  本文已影响0人  雾妖夜战先锋

最近碰到一个功能,需要将一张大图切割成若干个小图在拼成大图。

首先定义一些基础变量

    //小图的宽和高
    public int m_iMinWidth;
    public int m_iMinHeight;
    //一行有多少个小图
    public int m_iMinPicRowCount;
    //一列有多少个小图
    public int m_iMinPicColumnCount;
    //需要切割的大图
    public Texture2D m_texPlayer;
    //小图数组
    private Texture2D[,] m_texPlayers;

初始化一些变量

    //初始化行数列数
    m_iMinPicRowCount = 22;
    m_iMinPicColumnCount = 12;
    //根据行数和列数构造储存小图的数组
    m_texPlayers = new Texture2D[m_iMinPicRowCount, m_iMinPicRowCount];

核心方法 分割大图,核心思想就是在大图上去像素点赋值给小图

    //切图
    void DePackTexture(int i, int j)
    {
        //通过大图宽高计算出每次切图的大小
        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 通过从大图拿到的像素点赋值给小图
                newTexture.SetPixel(n - cur_x, m - cur_y, m_texPlayer.GetPixel(n, m));
            }
        }
        //Apply一下 更新贴图
        newTexture.Apply();
        //储存到数组
        m_texPlayers[i, j] = newTexture;

    }

有时候会碰到说大图不能读的情况,这是Unity为了节省性能默认的为不可读了,可以在设置中更改,也可以使用下面这个方法:

    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;
    }

调用下这个方法

m_texPlayer = duplicateTexture(m_texPlayer);

根据行列数分割大图

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

最后创建下Quad看下效果

    //创建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);
                //将材质赋给对应的Quad
                g.gameObject.GetComponent<MeshRenderer>().material.mainTexture = m_texPlayers[i, j];
            }
        }
    }

效果展示


image.png

但是这样会有一个问题,就是图片之间有很明显的缝隙感,这是由于创建的Texture2D大小并不能完美贴合所创建出来的Quad。
所以我们需要修改wrapMode,代码如下:

newTexture.wrapMode = TextureWrapMode.Clamp;

运行效果如下:


image.png

是不是就很完美了。

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