Unity 使用代码生成饼状图 PieChart

前言：

之前工作需要实现饼状图，这里记录一下用代码生成饼状图的方法.

最终效果如图

原理：

1.原理很简单，通过创建网格绘制各个饼状图基块，然后按角度合成即可.
2.如何创建网格，请直接看官方文档.
3.图像分析：


4.下面是生成饼状图的核心代码：

    /// <summary>
    /// 生成饼状图.
    /// </summary>
    private void GeneratePieChart()
    {
        float rot = 360.0f / num;
        for (int i = 0; i < num; i++)
        {
            Transform child = GenerateChildPieChart(3, num, height);   //饼状图基块.
            child.localRotation = Quaternion.Euler(0, rot * i, 0);      
            child.localPosition = new Vector3(0, height / 2.0f, 0);    
            child.gameObject.layer = LayerMask.NameToLayer("UI");
            child.SetParent(m_Transform, false);
            pieChartList.Add(child);
        }
        m_Transform.localScale = Vector3.one * 20;
        m_Transform.localRotation = Quaternion.Euler(90, 0, 0);
    }

    /// <summary>
    /// 创建饼状图基块.
    /// </summary>
    /// <param name="r">半径</param>
    /// <param name="num">份数</param>
	/// <param name="height">厚度</param>
	/// <returns></returns>
    private Transform GenerateChildPieChart(float r, int num, float height)
    {
        float y = r * Mathf.Sin((180.0f / num) * Mathf.Deg2Rad);
        float x = Mathf.Sqrt(r * r - y * y);
        Vector3 origin1 = new Vector3(0, 0, 0);
        Vector3 origin2 = new Vector3(x, 0, y);
        Vector3 origin3 = new Vector3(x, 0, -y);
        Vector3 offset = new Vector3(0, height, 0);
 
        Mesh mesh = new Mesh();
        Vector3[] vertices = new Vector3[6];
        vertices[0] = origin1;                  
        vertices[1] = origin2;
        vertices[2] = origin3;
        vertices[3] = vertices[0] - offset;     
        vertices[4] = vertices[1] - offset;
        vertices[5] = vertices[2] - offset;
        int[] triangles = new int[48] {     //双面都要.
            0, 1, 2, 3, 4, 5,   //顺时针 正面.
            0, 2, 5, 0, 5, 3, 
            0, 1, 4, 0, 4, 3,
            2, 1, 4, 2, 4, 5,

            0, 2, 1, 3, 5, 4,   //逆时针 反面.
            0, 5, 2, 0, 3, 5, 
            0, 4, 1, 0, 3, 4,
            2, 4, 1, 2, 5, 4 
        };
        mesh.vertices = vertices;
        mesh.triangles = triangles;

        GameObject temp = new GameObject();
        MeshFilter meshFilter = temp.AddComponent<MeshFilter>();
        meshFilter.mesh = mesh;

        MeshRenderer meshRenderer = temp.AddComponent<MeshRenderer>();
        //meshRenderer.material.shader = Shader.Find("Diffuse");
        meshRenderer.material = material_Other;

        return temp.transform;
    }

项目代码源文件.

完毕.