徒手画个disk不容易啊。。。

static const GLfloat disk_vertex_buffer_data[] = {
    // quarter 1
    0.0f, 0.0f, -1.0f, 
    0.707f, 0.0f, -0.707f, 
    0.612f, 0.354f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    0.612f, 0.354f, -0.707f, 
    0.354f, 0.612f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    0.354f, 0.612f, -0.707f, 
    0.0f, 0.707f, -0.707f, 

    0.707f, 0.0f, -0.707f, 
    1.0, 0.0f, 0.0f, 
    0.866f, 0.5f, 0.0f, 

    0.612f, 0.354f, -0.707f, 
    0.707f, 0.0f, -0.707f, 
    0.866f, 0.5f, 0.0f, 

    0.612f, 0.354f, -0.707f, 
    0.866f, 0.5f, 0.0f, 
    0.5f, 0.866f, 0.0f, 

    0.354f, 0.612f, -0.707f, 
    0.612f, 0.354f, -0.707f, 
    0.5f, 0.866f, 0.0f, 

    0.354f, 0.612f, -0.707f, 
    0.5f, 0.866f, 0.0f, 
    0.0f, 1.0f, 0.0f, 

    0.0f, 0.707f, -0.707f, 
    0.354f, 0.612f, -0.707f, 
    0.0f, 1.0f, 0.0f, 

    // quarter 2
    0.0f, 0.0f, -1.0f, 
    0.0f, 0.707f, -0.707f, 
    -0.354f, 0.612f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    -0.354f, 0.612f, -0.707f, 
    -0.612f, 0.354f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    -0.612f, 0.354f, -0.707f, 
    -0.707f, 0.0f, -0.707f, 

    0.0f, 0.707f, -0.707f, 
    0.0f, 1.0f, 0.0f, 
    -0.5f, 0.866f, 0.0f, 

    -0.354f, 0.612f, -0.707f, 
    0.0f, 0.707f, -0.707f, 
    -0.5f, 0.866f, 0.0f, 
    
    -0.354f, 0.612f, -0.707f, 
    -0.5f, 0.866f, 0.0f, 
    -0.866f, 0.5f, 0.0f, 

    -0.612f, 0.354f, -0.707f, 
    -0.354f, 0.612f, -0.707f, 
    -0.866f, 0.5f, 0.0f, 

    -0.612f, 0.354f, -0.707f, 
    -0.866f, 0.5f, 0.0f, 
    -1.0f, 0.0f, 0.0f, 

    -0.707f, 0.0f, -0.707f, 
    -0.612f, 0.354f, -0.707f, 
    -1.0f, 0.0f, 0.0f, 

    // quarter 3
    0.0f, 0.0f, -1.0f, 
    -0.707f, 0.0f, -0.707f, 
    -0.612f, -0.354f, -0.707f, 
    
    0.0f, 0.0f, -1.0f, 
    -0.866f, -0.354f, -0.707f, 
    -0.354f, -0.612f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    -0.354f, -0.612f, -0.707f, 
    0.0f, -0.707f, -0.707f, 

    -0.707f, 0.0f, -0.707f, 
    -1.0f, 0.0f, 0.0f, 
    -0.866f, -0.5f, 0.0f, 

    -0.612f, -0.354f, -0.707f, 
    -0.707f, 0.0f, -0.707f, 
    -0.866f, -0.5f, 0.0f, 

    -0.612f, -0.354f, -0.707f, 
    -0.866f, -0.5f, 0.0f, 
    -0.5f, -0.866f, 0.0f, 

    -0.354f, -0.612f, -0.707f, 
    -0.612f, -0.354f, -0.707f, 
    -0.5f, -0.866f, 0.0f, 

    -0.354f, -0.612f, -0.707f, 
    -0.5f, -0.866f, 0.0f, 
    0.0f, -1.0f, 0.0f, 

    0.0f, -0.707f, -0.707f, 
    -0.354f, -0.612f, -0.707f, 
    0.0f, -1.0f, 0.0f, 

    // quarter 4
    0.0f, 0.0f, -1.0f, 
    0.0f, -0.707f, -0.707f, 
    0.354f, -0.612f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    0.354f, -0.612f, -0.707f, 
    0.612f, -0.354f, -0.707f, 

    0.0f, 0.0f, -1.0f, 
    0.612f, -0.354f, -0.707f, 
    0.707f, 0.0f, -0.707f, 

    0.0f, -0.707f, -0.707f, 
    0.0f, -1.0f, 0.0f, 
    0.5f, -0.866f, 0.0f, 

    0.354f, -0.612f, -0.707f, 
    0.0f, -0.707f, -0.707f, 
    0.5f, -0.866f, 0.0f, 

    0.354f, -0.612f, -0.707f, 
    0.5f, -0.866f, 0.0f, 
    0.866f, -0.5f, 0.0f, 

    0.612f, -0.354f, -0.707f, 
    0.354f, -0.612f, -0.707f, 
    0.866f, -0.5f, 0.0f, 

    0.612f, -0.354f, -0.707f, 
    0.866f, -0.5f, 0.0f, 
    1.0f, 0.0f, 0.0f, 

    0.707f, 0.0f, -0.707f, 
    0.612f, -0.354f, -0.707f, 
    1.0f, 0.0f, 0.0f, 
};