After installing Yosemite, I had to upgrade numpy, PyOpenGL, etc.
Now, a previously-working program is giving me the following stack trace:
file "latebind.pyx", line 44, in OpenGL_accelerate.latebind.Curry.__call__ (src/latebind.c:1201) File "/opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/OpenGL/GL/VERSION/GL_1_5.py", line 89, in glBufferData return baseOperation( target, size, data, usage ) File "latebind.pyx", line 32, in OpenGL_accelerate.latebind.LateBind.__call__ (src/latebind.c:989) File "wrapper.pyx", line 314, in OpenGL_accelerate.wrapper.Wrapper.__call__ (src/wrapper.c:6505) File "wrapper.pyx", line 311, in OpenGL_accelerate.wrapper.Wrapper.__call__ (src/wrapper.c:6439) ctypes.ArgumentError: ("argument 3: <class 'OpenGL.error.CopyError'>: from_param received a non-contiguous array! []", (GL_ARRAY_BUFFER, 0, array([], dtype=[('time', '<f8'), ('data', [('cluster_index', '<i4'), ('delta_diag_out', '<f8')])]), GL_STREAM_DRAW)) It looks like PyOpenGL wants my array to be contiguous. Looking at the source in numpy_formathandler.pyx in PyOpenGL:
if not PyArray_ISCARRAY( instance ): raise CopyError( """from_param received a non-contiguous array! %s"""%( working, ) ) And PyArray_ISCARRAY(arr) "Evaluates true if the data area of arr is C-style contiguous, and PyArray_ISBEHAVED (arr) is true." Whereby "PyArray_ISBEHAVED(arr) Evalutes true if the data area of arr is aligned and writeable and in machine byte-order according to its descriptor."
However, the flags attribute of the array that was pushed to OpenGL is:
C_CONTIGUOUS : True F_CONTIGUOUS : True OWNDATA : False WRITEABLE : True ALIGNED : False UPDATEIFCOPY : False Perhaps I need to align the array? But using numpy.require with requirements={'ALIGNED': True} doesn't seem to work.
I looked at the changes in numpy 1.9, which indicate:
NPY_RELAXED_STRIDES_CHECKING=1 python setup.py install
You can check whether NPY_RELAXED_STRIDES_CHECKING is in effect by running:
np.ones((10, 1), order="C").flags.f_contiguous
This will be True if relaxed strides checking is enabled, and False otherwise. The typical problem we’ve seen so far is C code that works with C-contiguous arrays, and assumes that the itemsize can be accessed by looking at the last element in the PyArray_STRIDES(arr) array. When relaxed strides are in effect, this is not true (and in fact, it never was true in some corner cases). Instead, use PyArray_ITEMSIZE(arr).
However, np.ones((10, 1), order="C").flags.f_contiguous is False on my system. So I'm stumped. What changed that is causing opengl to think that the arrays I'm sending it are not contiguous and aligned? Is there a way to align an array by force?