def marching_cubes(volume, smooth=True, decimate=True, **kwargs):
from tvtk.api import tvtk
from tvtk.common import configure_input
imgdata = tvtk.ImageData(dimensions=volume.shape)
imgdata.point_data.scalars = volume.flatten('F')
contours = tvtk.ContourFilter(number_of_contours=1)
contours.set_value(0, 1)
configure_input(contours, imgdata)
if smooth:
smoothargs = dict(number_of_iterations=40,
feature_angle=90,
pass_band=.05)
smoothargs.update(kwargs)
contours = tvtk.WindowedSincPolyDataFilter(input=contours.output,
**smoothargs)
if decimate:
contours = tvtk.QuadricDecimation(input=contours.output,
target_reduction=.75)
contours.update()
pts = contours.output.points.to_array()
polys = contours.output.polys.to_array().reshape(-1, 4)[:, 1:]
return pts, polys
def _decimate_surface(points, triangles, reduction):
"""Aux function"""
if 'DISPLAY' not in os.environ and sys.platform != 'win32':
os.environ['ETS_TOOLKIT'] = 'null'
try:
from tvtk.api import tvtk
except ImportError:
raise ValueError('This function requires the TVTK package to be '
'installed')
if triangles.max() > len(points) - 1:
raise ValueError('The triangles refer to undefined points. '
'Please check your mesh.')
src = tvtk.PolyData(points=points, polys=triangles)
decimate = tvtk.QuadricDecimation(input=src, target_reduction=reduction)
decimate.update()
out = decimate.output
tris = out.polys.to_array()
# n-tuples + interleaved n-next -- reshape trick
return out.points.to_array(), tris.reshape(tris.size / 4, 4)[:, 1:]
