我使用PyOpenGL与PyQt5部件。在我的OpenGL widget中，我有以下代码：

class Renderizador(QOpenGLWidget):

    def __init__(self, parent=None):
        super().__init__(parent)
        self._x = -0.1
        self._y = -0.1
        self._z = -0.1
        self._rx = 45
        self._ry = 45
        self._rz = -45
        self.vertices_vertical = [[100, 100, 0], [100, -100, 0],
                                  [-100, -100, 0], [-100, 100, 0]]
        self.vertices_horizontal = [[100, 0, -100], [100, 0, 100],
                                    [-100, 0, 100], [-100, 0, -100]]

    def initializeGL(self):
        glClear(GL_COLOR_BUFFER_BIT)
        glEnable(GL_DEPTH_TEST)
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        glOrtho(-1, 1, 1, -1, -15, 1)
        glTranslate(self._x, self._y, self._z)
        glRotate(self._rx, 1, 0, 0)
        glRotate(self._ry, 0, 1, 0)
        glRotate(self._rz, 0, 0, 0)

    def paintGL(self):
        glClearColor(1, 1, 1, 1)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()

        glTranslate(self._x, self._y, self._z)
        glRotate(self._rx, 1, 0, 0)
        glRotate(self._ry, 0, 1, 0)
        glRotate(self._rz, 0, 0, 1)

        # Axis lines
        glBegin(GL_LINES)

        glColor3d(1, 0, 0)
        glVertex3d(0, 0, 0)
        glVertex3d(1, 0, 0)

        glColor3d(0, 1, 0)
        glVertex3d(0, 0, 0)
        glVertex3d(0, 1, 0)

        glColor3d(0, 0, 1)
        glVertex3d(0, 0, 0)
        glVertex3d(0, 0, 1)

        glEnd()

        # Plane drawing, does not work
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_DST_COLOR)
        glBegin(GL_QUADS)
        glColor4fv((0, 1, 0, 0.6))
        for vertex in range(4):
            glVertex3fv(self.vertices_vertical[vertex])
        glColor4fv((1, 0, 0, 0.6))
        for vertex in range(4):
            glVertex3fv(self.vertices_horizontal[vertex])
        glEnd()
        glDisable(GL_BLEND)

为什么这两个平面没有渲染？我把背景色改成了白色，用了glClearColor，然后用了glClear函数，然后才这样做。我能看到轴线，但看不到我画的平面。