AnimateVectors
vtk-examples/Python/Texture/AnimateVectors
Description¶
Texture maps can be animated as a function of time. By choosing a texture map whose intensity varies monotonically from dark to light, and then “moving” the texture along an object,the object appears to crawl in the direction of the texture map motion. We can use this technique to add apparent motion to things like hedgehogs to show vector magnitude. This example uses texture map animation to simulate vector field motion.
Cite
See B. Yamrom and K. M. Martin. Vector Field Animation with Texture Maps. IEEE Computer Graphics and Applications. 15(2):22–24, 1995 for background.
Info
See Figure 7-3 in Chapter 7 the VTK Textbook.
Other languages
See (Cxx)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
AnimateVectors.py
#!/usr/bin/env python
from pathlib import Path
# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkFiltersCore import (
vtkGlyph3D,
vtkThresholdPoints
)
from vtkmodules.vtkFiltersModeling import vtkOutlineFilter
from vtkmodules.vtkFiltersSources import vtkLineSource
from vtkmodules.vtkIOLegacy import vtkStructuredPointsReader
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkCamera,
vtkPolyDataMapper,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer,
vtkTexture
)
def main():
vec_anim_paths = [''] * 2
fn1, fn2 = get_program_parameters()
vec_anim_paths[0] = Path(fn1)
vec_anim_paths[1] = Path(fn2)
# Generate the other vecAnim file names. There are 8 of them.
tmp = str(vec_anim_paths[1])
old_stem = vec_anim_paths[1].stem
for i in range(2, 9):
new_stem = old_stem[:-1] + str(i)
vec_anim_paths.append(Path(tmp.replace(old_stem, new_stem)))
colors = vtkNamedColors()
# Setup the render window, renderer, and interactor.
renderer = vtkRenderer()
renderWindow = vtkRenderWindow()
renderWindow.AddRenderer(renderer)
interactor = vtkRenderWindowInteractor()
interactor.SetRenderWindow(renderWindow)
# Read the data.
# Create the pipeline.
reader = vtkStructuredPointsReader()
reader.SetFileName(vec_anim_paths[0])
threshold = vtkThresholdPoints()
threshold.SetInputConnection(reader.GetOutputPort())
threshold.ThresholdByUpper(200)
line = vtkLineSource()
line.SetResolution(1)
lines = vtkGlyph3D()
lines.SetInputConnection(threshold.GetOutputPort())
lines.SetSourceConnection(line.GetOutputPort())
lines.SetScaleFactor(0.005)
lines.SetScaleModeToScaleByScalar()
lines.Update()
vectorMapper = vtkPolyDataMapper()
vectorMapper.SetInputConnection(lines.GetOutputPort())
vectorMapper.SetScalarRange(lines.GetOutput().GetScalarRange())
vectorActor = vtkActor()
vectorActor.SetMapper(vectorMapper)
vectorActor.GetProperty().SetOpacity(0.99)
vectorActor.GetProperty().SetLineWidth(1.5)
# Outline
outline = vtkOutlineFilter()
outline.SetInputConnection(reader.GetOutputPort())
outlineMapper = vtkPolyDataMapper()
outlineMapper.SetInputConnection(outline.GetOutputPort())
outlineActor = vtkActor()
outlineActor.SetMapper(outlineMapper)
outlineActor.GetProperty().SetColor(colors.GetColor3d('Black'))
# Texture maps.
textureMaps = list()
for i in range(2, len(vec_anim_paths)):
tmap = vtkStructuredPointsReader()
tmap.SetFileName(vec_anim_paths[i])
texture = vtkTexture()
texture.SetInputConnection(tmap.GetOutputPort())
texture.InterpolateOff()
texture.RepeatOff()
textureMaps.append(texture)
vectorActor.SetTexture(textureMaps[0])
# Add the actors to the renderer, set the background and size.
renderer.AddActor(vectorActor)
renderer.AddActor(outlineActor)
cam1 = vtkCamera()
cam1.SetClippingRange(17.4043, 870.216)
cam1.SetFocalPoint(136.71, 104.025, 23)
cam1.SetPosition(204.747, 258.939, 63.7925)
cam1.SetViewUp(-0.102647, -0.210897, 0.972104)
cam1.Zoom(1.2)
renderer.SetActiveCamera(cam1)
renderer.SetBackground(colors.GetColor3d('Wheat'))
renderWindow.SetSize(640, 480)
renderWindow.SetWindowName('AnimateVectors')
# Go into a loop.
for j in range(0, 100):
for i in range(0, len(textureMaps)):
vectorActor.SetTexture(textureMaps[i])
renderWindow.Render()
interactor.Start()
def get_program_parameters():
import argparse
description = 'Texture maps can be animated as a function of time.'
epilogue = '''
This example uses texture map animation to simulate vector field motion.
'''
parser = argparse.ArgumentParser(description=description, epilog=epilogue,
formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('filename1', help='carotid.')
parser.add_argument('filename2', help='VectorAnimation/vecAnim1.vtk.')
args = parser.parse_args()
return args.filename1, args.filename2
if __name__ == '__main__':
main()