Hi All,
I am quite new to vtk and I am trying to do a volume rendering of a vtkImageDataset in parallel using vtkcompositeendermanger. I am following these two examples
[1] (https://gitlab.kitware.com/vtk/vtk/-/blob/fdc214b9c2c6f911b66588fc898a932da0aa6755/Examples/ParallelProcessing/MPI/Python/ParallelCone.py)
2
The second example above uses translucent cut planes to get pseudo volume rendering. I facing difficulties to implement this in parallel. When the cut planes are set to be opaque (alpha = 1) the rendering works fine. However, when the planes are made translucent I get empty windows on the head rank. I tried turning SetUseRGBA() option on. But, this did not help. I have attached my script below. Is this some issue with MPI communication? Any help would be appreciated
Thanks,
Hari
rootdir = r"./"
myrank = 0
myrank = comm.Get_rank()
n_ranks = contr.GetNumberOfProcesses()
rd = RunData([‘T’,‘P’],[120.0,1.41837E+05/101325],rootdir,halo=True,comm=comm,topo=[4,1,1])
alg = S3D_source(rd,myrank,timestep=“all”)
alg.Update()
alg_out = alg.GetOutputDataObject(0)
alg_out.GetPointData().SetActiveScalars(“T”)
local_range = alg_out.GetScalarRange()
gmin = comm.allreduce(local_range[0],op=MPI.MIN)
gmax = comm.allreduce(local_range[1],op=MPI.MAX)
local_range = [gmin,gmax]
#create a color lookup table
lut = vtk.vtkLookupTable()
lut.SetHueRange(0.667, 0.0)
lut.SetNumberOfColors(256)
lut.SetAlphaRange(0.5,0.5)
lut.Build()
#create a color lookup table
lut1 = vtk.vtkLookupTable()
lut1.SetHueRange(0.667, 0.0)
lut1.SetNumberOfColors(256)
lut1.Build()
#get a cutting plane
plane = vtk.vtkPlane()
local_origin = rd.origin_for_processor(myrank,0,0)
plane.SetOrigin(0,0,0)
plane.SetNormal(0,0,1)
#create a cutter to cut the data using the above plane
cutter = vtk.vtkCutter()
cutter.SetInputConnection(alg.GetOutputPort())
cutter.SetCutFunction(plane)
cutter.GenerateCutScalarsOff()
cutter.SetSortByToSortByCell()
#create mapper for the polydata from cutter
cutterMapper = vtk.vtkPolyDataMapper()
cutterMapper.SetInputConnection(cutter.GetOutputPort())
cutterMapper.SetScalarRange(local_range[0], local_range[1])
#choose which array to use for mapping to color
cutterMapper.ScalarVisibilityOn()
cutterMapper.SetScalarModeToUsePointFieldData()
cutterMapper.SelectColorArray(“T”)
cutterMapper.SetColorModeToMapScalars()
cutterMapper.SetLookupTable(lut)
cutactor = vtk.vtkActor()
cutactor.SetMapper(cutterMapper)
iso = vtk.vtkContourFilter()
alg_out = alg.GetOutputDataObject(0)
alg_out.GetPointData().SetActiveScalars("T")
iso.SetInputData(alg_out)
iso.SetValue(0, 1850)
iso.SetValue(1, 1000)
normals = vtk.vtkPolyDataNormals()
normals.SetInputConnection(iso.GetOutputPort())
normals.SetFeatureAngle(45)
isoMapper = vtk.vtkPolyDataMapper()
isoMapper.SetInputConnection(normals.GetOutputPort())
isoMapper.ScalarVisibilityOn()
isoMapper.SetScalarModeToUsePointFieldData()
isoMapper.SelectColorArray("T")
isoMapper.SetScalarRange(local_range[0],local_range[1])
isoMapper.SetColorModeToMapScalars()
isoMapper.SetLookupTable(lut1)
isoActor = vtk.vtkActor()
isoActor.SetMapper(isoMapper)
#create colorbar
prop = vtk.vtkTextProperty()
prop.SetColor(0.0,0.0,0.0)
prop.SetFontSize(1)
cb = vtk.vtkScalarBarActor()
cb.SetLookupTable(lut)
cb.SetTitle(“T”)
cb.SetPosition(0.8,0.2)
cb.SetBarRatio(0.2)
cb.SetHeight(0.7)
cb.SetLabelTextProperty(prop)
cb.SetTitleTextProperty(prop)
ren = vtk.vtkRenderer()
ren.AddActor(cutactor)
#ren.AddActor(isoActor)
cutactor.VisibilityOn()
cutactor.RotateX(30)
isoActor.RotateX(30)
cutactor.RotateY(45)
isoActor.RotateY(45)
if(myrank == 0):
ren.AddActor2D(cb)
ren.SetBackground(1.0, 1.0, 1.0)
ren.ResetCamera()
cam = ren.GetActiveCamera()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
renWin.SetSize(1920, 1080)
#now generate cut planes
cutter.GenerateValues(100,-0.02,0.02)
#lut.Build()
renWin.Render()
ren_manager = vtk.vtkCompositeRenderManager()
tsteps = rd.get_times()
ren_manager.SetController(contr)
ren_manager.SetRenderWindow(renWin)
ren_manager.SetUseRGBA(0)
tid = 0
if(myrank == 0):
if(tid == 0):
ren_manager.ResetAllCameras()
cam.Zoom(1.5)
renWin.Render()
w2if = vtk.vtkWindowToImageFilter()
w2if.SetInput(renWin)
writer = vtk.vtkPNGWriter()
writer.SetInputData(w2if.GetOutput())
w2if.Update()
filename = './figs/screenshot%d'%tid
filename = filename + '.png'
writer.SetFileName(filename)
writer.Write()
for i in range(1,n_ranks):
contr.TriggerRMI(i,contr.GetBreakRMITag())
else:
ren_manager.InitializeRMIs()
contr.ProcessRMIs()
print("after process:",tid,myrank)
contr.Finalize()