unity 生成指定半径和细分数的球体

A：

在Unity中，可以使用自带的CreatePrimitive函数创建球体，其可以指定半径，但无法指定细分数。如果需要更加细致的球体，可以使用Unity相关的网格编辑器或者自行编写算法。

以下是使用Unity自带的CreatePrimitive函数创建球体的代码：

GameObject sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
sphere.transform.localScale = new Vector3(radius, radius, radius);

其中，radius为球体的半径。如果需要更细致的球体，可以使用Unity自带的球体模型，并通过脚本设置其半径和细分数。

GameObject sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
sphere.transform.localScale = new Vector3(radius, radius, radius);

Mesh sphereMesh = sphere.GetComponent<MeshFilter>().mesh;
sphereMesh.RecalculateNormals();
sphereMesh.RecalculateBounds();

Vector3[] newVertices = sphereMesh.vertices;

for(int i = 0; i < sphereMesh.triangles.Length; i += 3)
{
    Vector3 v1 = newVertices[sphereMesh.triangles[i]];
    Vector3 v2 = newVertices[sphereMesh.triangles[i+1]];
    Vector3 v3 = newVertices[sphereMesh.triangles[i+2]];

    for(int j = 0; j < recursionLevel; j++)
    {
        Vector3 v1mid = Vector3.Lerp(v1, v2, 0.5f);
        Vector3 v2mid = Vector3.Lerp(v2, v3, 0.5f);
        Vector3 v3mid = Vector3.Lerp(v3, v1, 0.5f);

        newVertices[sphereMesh.triangles[i]] = v1;
        newVertices[sphereMesh.triangles[i+1]] = v2;
        newVertices[sphereMesh.triangles[i+2]] = v3;
        newVertices[newVertices.Length] = v1mid;
        newVertices[newVertices.Length] = v2mid;
        newVertices[newVertices.Length] = v3mid;

        sphereMesh.triangles[i] = newVertices.Length - 3;
        sphereMesh.triangles[i+1] = newVertices.Length - 2;
        sphereMesh.triangles[i+2] = newVertices.Length - 1;

        v1 = v1mid;
        v2 = v2mid;
        v3 = v3mid;
    }
}

sphereMesh.vertices = newVertices;
sphereMesh.RecalculateNormals();
sphereMesh.RecalculateBounds();

其中，radius为球体的半径，recursionLevel为细分数。