[Discuss-gnuradio] coerce endpoint - hier block API question with code

[Marius]

Hi!

I'm creating an integration for the current GNU Radio >= 3.4 tree
upwards for a 3d FFT display block.
I put the code I got there, and added some changes:
https://github.com/wishi/gr_3d_fft

My probem is:

Traceback (most recent call last):
  File "usrp_gl_fft.py", line 81, in <module>
    main ()
  File "usrp_gl_fft.py", line 77, in main
    app = stdgui2.stdapp(app_flow_graph, "3d")
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py",
line 36, in __init__
    wx.App.__init__ (self, redirect=False)
  File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py",
line 7978, in __init__
    self._BootstrapApp()
  File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py",
line 7552, in _BootstrapApp
    return _core_.PyApp__BootstrapApp(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py",
line 39, in OnInit
    frame = stdframe (self.top_block_maker, self.title, self._nstatus)
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py",
line 60, in __init__
    self.panel = stdpanel (self, self, top_block_maker)
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/wxgui/stdgui2.py",
line 81, in __init__
    self.top_block = top_block_maker (frame, self, vbox, sys.argv)
  File "usrp_gl_fft.py", line 74, in __init__
    self.connect (self.u, block)
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/top_block.py",
line 124, in connect
    self._connect(points[i-1], points[i])
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/top_block.py",
line 128, in _connect
    (dst_block, dst_port) = self._coerce_endpoint(dst)
  File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/top_block.py",
line 139, in _coerce_endpoint
    raise ValueError("unable to coerce endpoint")
ValueError: unable to coerce endpoint

I know this is related to the hierarchical block API, but I don't know
what I have to change. Could someone help me - at least a little?
I think there's too much to do left, however I don't find a way to
treat this error.
If that works I'll do GRC integration and clean up the OpenGL stuff
(the code is from the source mentioned in the repository, but GPL).
I'm missing this kind of 3d perspective so I tried to create this
graphical sink based on the mentioned code.

Thanks in advance ;),
Marius