def drawCoordinate():
  '''
  绘制三维的坐标系，并绘制由坐标轴构成的平面的网格，各个坐标轴的颜色以及由坐标轴所引出的网格线的颜色为：
  x: (1.0, 0.0, 0.0)
  y: (0.0, 1.0, 0.0)
  z: (0.0, 0.0, 1.0)
  :return:
  '''
  #设置网格线间的步长
  step = 0.2
  #设置网格线的数量、长度
  line_num = 15
  line_len = 4
  grid_color = [(1.0, 0.0, 0.0), (0.0, 1.0, 0.0), (0.0, 0.0, 1.0)]

  glLineWidth(3)
  origin = [0.0, 0.0, 0.0]
  #画出xyz轴
  for i in range(3):
    tmp = [0.0, 0.0, 0.0]
    tmp[i] = line_len*1.02
    glColor3f(*grid_color[i])
    glBegin(GL_LINES)
    glVertex3f(*origin)
    glVertex3f(*tmp)
    glEnd()


  # 画出由坐标轴构成的平面的网格
  glLineWidth(1)
  for i in range(3):
  	#每次把一个坐标轴上引出的网格线都画出来，所以起点都是一致的
    start = [0.0, 0.0, 0.0]
    glColor3f(*grid_color[i])
    for j in range(line_num):
      end = [0.0, 0.0, 0.0]
      glBegin(GL_LINES)
      start[i] = start[i] + step
      end[i] = start[i]
      for k in {0,1,2} - {i,}:
        end[k] = line_len
        glVertex3f(*start)
        glVertex3f(*end)
        end[k] = 0.0
      glEnd()