一：主要的知识点
1、说明
本文只是教程内容的一小段，因博客字数限制，故进行拆分。主教程链接：vtk教程------逐行解析官网所有Python示例-CSDN博客
2、知识点纪要
本段代码主要涉及的有①vtkMaskPoints点采样
二：代码及注释
python
#!/usr/bin/env python3
"""
Demonstrate all the parametric objects.
"""
from pathlib import Path
# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingFreeType
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonComputationalGeometry import (
vtkParametricBohemianDome,
vtkParametricBour,
vtkParametricBoy,
vtkParametricCatalanMinimal,
vtkParametricConicSpiral,
vtkParametricCrossCap,
vtkParametricDini,
vtkParametricEllipsoid,
vtkParametricEnneper,
vtkParametricFigure8Klein,
vtkParametricHenneberg,
vtkParametricKlein,
vtkParametricKuen,
vtkParametricMobius,
vtkParametricPluckerConoid,
vtkParametricPseudosphere,
vtkParametricRandomHills,
vtkParametricRoman,
vtkParametricSpline,
vtkParametricSuperEllipsoid,
vtkParametricSuperToroid,
vtkParametricTorus
)
from vtkmodules.vtkCommonCore import (
vtkMinimalStandardRandomSequence,
vtkPoints
)
from vtkmodules.vtkFiltersCore import (
vtkGlyph3D,
vtkMaskPoints
)
from vtkmodules.vtkFiltersSources import (
vtkArrowSource,
vtkParametricFunctionSource
)
from vtkmodules.vtkIOImage import (
vtkPNGWriter
)
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkActor2D,
vtkPolyDataMapper,
vtkProperty,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer,
vtkTextMapper,
vtkTextProperty,
vtkWindowToImageFilter
)
def get_program_parameters():
import argparse
description = 'Display the parametric surfaces.'
epilogue = '''
'''
parser = argparse.ArgumentParser(description=description, epilog=epilogue,
formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('-s', '--surface_name', default=None, help='The name of the surface.')
parser.add_argument('-b', '--back_face', action='store_true', help='Color the back face.')
parser.add_argument('-n', '--normals', action='store_true', help='Display normals.')
parser.add_argument('-l', '--limits', action='store_true', help='Display the geometric bounds of the object..')
args = parser.parse_args()
return args.surface_name, args.back_face, args.normals, args.limits
def main():
back_face = True
normals = True
# Get the parametric functions and build the pipeline
pfn = get_parametric_functions()
renderer_size = 200
grid_column_dimensions = 5
grid_row_dimensions = 5
colors = vtkNamedColors()
# Create one text property for all.
text_property = vtkTextProperty()
text_property.SetJustificationToCentered()
text_property.SetFontSize(int(renderer_size / 12))
text_property.SetColor(colors.GetColor3d("LavenderBlush"))
# Create a parametric function source, renderer, mapper, and actor
# for each object.
pfn_srcs = []
renderers = []
mappers = []
actors = []
text_mappers = []
text_actors = []
# Glyph the normals.
mask_pts = []
arrow = []
glyph = []
glyph_mapper = []
glyph_actor = []
back_property = vtkProperty()
if back_face:
back_property.SetColor(colors.GetColor3d("Peru"))
# Now decide on the surfaces to build.
surfaces = pfn
# The bounding boxes for each object.
bounding_boxes = dict()
indexed_names = dict()
# The index of each parametric object.
obj_idx = -1
sorted_names = list()
for obj in sorted(surfaces.keys()):
obj_idx += 1
indexed_names[obj_idx] = obj
pfn_srcs.append(vtkParametricFunctionSource())
pfn_srcs[obj_idx].SetParametricFunction(surfaces[obj])
"""
下面三段代码是用来设置参数化曲面源的分辨率，会直接影响最终生成模型的光滑度和细节
三个方法共同决定了从数学公式生成的网格密度
"""
pfn_srcs[obj_idx].SetUResolution(51)
pfn_srcs[obj_idx].SetVResolution(51)
pfn_srcs[obj_idx].SetWResolution(51)
pfn_srcs[obj_idx].Update()
mappers.append(vtkPolyDataMapper())
mappers[obj_idx].SetInputConnection(pfn_srcs[obj_idx].GetOutputPort())
actors.append(vtkActor())
actors[obj_idx].SetMapper(mappers[obj_idx])
actors[obj_idx].GetProperty().SetColor(colors.GetColor3d("NavajoWhite"))
if back_face:
actors[obj_idx].SetBackfaceProperty(back_property)
text_mappers.append(vtkTextMapper())
text_mappers[obj_idx].SetInput(obj)
text_mappers[obj_idx].SetTextProperty(text_property)
text_actors.append(vtkActor2D())
text_actors[obj_idx].SetMapper(text_mappers[obj_idx])
text_actors[obj_idx].SetPosition(renderer_size / 2.0, 8)
renderers.append(vtkRenderer())
renderers[obj_idx].SetBackground(colors.GetColor3d("MidnightBlue"))
bounds = pfn_srcs[obj_idx].GetOutput().GetBounds()
bounding_boxes[obj] = bounds
if normals:
# Glyphing
"""
vtkMaskPoints()
主要作用是从一个数据集中选择（或"遮罩"）一部分点，并将它们作为新的输出。
简单来说，它就像一个"点选择器"，能让你从海量点数据中挑出你想要的那一部分
"""
mask_pts.append(vtkMaskPoints())
"""
多种选择点的模式
RandomModeOn 随机选择
SetOnRatio(10) 均匀间隔选择 每隔10个点选择一个
SetMaskOnBounds() 只选择边界框之内的点
"""
mask_pts[obj_idx].RandomModeOn()
mask_pts[obj_idx].SetMaximumNumberOfPoints(150)
mask_pts[obj_idx].SetInputConnection(pfn_srcs[obj_idx].GetOutputPort())
arrow.append(vtkArrowSource())
arrow[obj_idx].SetTipResolution(16) # 设置箭尖的分辨率，越大越平滑
arrow[obj_idx].SetTipLength(0.3) # 设置箭尖的长度， 0.3是一个相对于箭头总长度的值
arrow[obj_idx].SetTipRadius(0.1) # 设置箭杆的半径
glyph_scale = get_maximum_length(bounding_boxes[obj])
glyph.append(vtkGlyph3D())
glyph[obj_idx].SetSourceConnection(arrow[obj_idx].GetOutputPort())
glyph[obj_idx].SetInputConnection(mask_pts[obj_idx].GetOutputPort())
# SetVectorModeToUseNormal 设置向量模式 使用输入点上的法线向量来控制字形的方向
glyph[obj_idx].SetVectorModeToUseNormal()
# SetScaleFactor 设置缩放因子，决定每个箭头的大小
glyph[obj_idx].SetScaleFactor(glyph_scale / 10.0)
# OrientOn 启用定向功能，是SetVectorModeToUseNormal的一个补充， 在放置箭头时，要根据法线向量的方向来旋转箭头
glyph[obj_idx].OrientOn()
glyph[obj_idx].Update()
glyph_mapper.append(vtkPolyDataMapper())
glyph_mapper[obj_idx].SetInputConnection(
glyph[obj_idx].GetOutputPort())
glyph_actor.append(vtkActor())
glyph_actor[obj_idx].SetMapper(glyph_mapper[obj_idx])
glyph_actor[obj_idx].GetProperty().SetColor(colors.GetColor3d("GreenYellow"))
# Need a renderer even if there is no actor.
for i in range(obj_idx + 1, grid_column_dimensions * grid_row_dimensions):
renderers.append(vtkRenderer())
renderers[i].SetBackground(colors.GetColor3d("MidnightBlue"))
sorted_names.append(None)
ren_win = vtkRenderWindow()
ren_win.SetSize(renderer_size * grid_column_dimensions, renderer_size * grid_row_dimensions)
for row in range(0, grid_row_dimensions):
for col in range(0, grid_column_dimensions):
index = row * grid_column_dimensions + col
# (xmin, ymin, xmax, ymax)
viewport = [
float(col) * renderer_size / (grid_column_dimensions * renderer_size),
float(grid_row_dimensions - (row + 1)) * renderer_size / (grid_row_dimensions * renderer_size),
float(col + 1) * renderer_size / (grid_column_dimensions * renderer_size),
float(grid_row_dimensions - row) * renderer_size / (grid_row_dimensions * renderer_size)]
ren_win.AddRenderer(renderers[index])
renderers[index].SetViewport(viewport)
if index > obj_idx:
continue
renderers[index].AddActor(actors[index])
# Normals can only be computed for polygons and triangle strips.
# The Spline is a line.
if normals and indexed_names[index] != 'Spline':
renderers[index].AddActor(glyph_actor[index])
renderers[index].AddActor(text_actors[index])
renderers[index].ResetCamera()
renderers[index].GetActiveCamera().Azimuth(30)
renderers[index].GetActiveCamera().Elevation(-30)
renderers[index].GetActiveCamera().Zoom(0.9)
renderers[index].ResetCameraClippingRange()
iren = vtkRenderWindowInteractor()
iren.SetRenderWindow(ren_win)
fn = 'ParametricObjectsDemo'
ren_win.SetWindowName(fn)
print_callback = PrintCallback(iren, fn, 1, False)
iren.AddObserver('KeyPressEvent', print_callback)
iren.Initialize()
iren.Start()
def get_parametric_functions():
pfn = dict()
pfn['Boy'] = vtkParametricBoy()
pfn['ConicSpiral'] = vtkParametricConicSpiral()
pfn['CrossCap'] = vtkParametricCrossCap()
pfn['Dini'] = vtkParametricDini()
pfn['Ellipsoid'] = vtkParametricEllipsoid()
pfn['Enneper'] = vtkParametricEnneper()
pfn['Figure8Klein'] = vtkParametricFigure8Klein()
pfn['Klein'] = vtkParametricKlein()
pfn['Mobius'] = vtkParametricMobius()
pfn['RandomHills'] = vtkParametricRandomHills()
pfn['Roman'] = vtkParametricRoman()
pfn['SuperEllipsoid'] = vtkParametricSuperEllipsoid()
pfn['SuperToroid'] = vtkParametricSuperToroid()
pfn['Torus'] = vtkParametricTorus()
pfn['Spline'] = vtkParametricSpline()
# Extra parametric surfaces.
pfn['BohemianDome'] = vtkParametricBohemianDome()
pfn['Bour'] = vtkParametricBour()
pfn['CatalanMinimal'] = vtkParametricCatalanMinimal()
pfn['Henneberg'] = vtkParametricHenneberg()
pfn['Kuen'] = vtkParametricKuen()
pfn['PluckerConoid'] = vtkParametricPluckerConoid()
pfn['Pseudosphere'] = vtkParametricPseudosphere()
# 设置某些参数
pfn["Ellipsoid"].SetXRadius(0.5) # 将椭球体在 X 方向的半径设置为 0.5
pfn["Ellipsoid"].SetYRadius(2.0) # 将椭球体在 Y 方向的半径设置为 2.0
pfn["Mobius"].SetRadius(2.0) # 设置莫比乌斯带的半径为 2.0
pfn["Mobius"].SetMinimumV(-0.5) # 设置 V 参数的最小值为 -0.5
pfn["Mobius"].SetMaximumV(0.5) # 设置 V 参数的最大值为 0.5
pfn["RandomHills"].AllowRandomGenerationOn() # 启用随机山丘曲面的随机生成功能
pfn["RandomHills"].SetRandomSeed(1)
pfn["RandomHills"].SetNumberOfHills(30) # 设置生成的山丘数量为 30 个
# 通过调整 N1 和 N2 参数，可以改变超椭球体的形状，使其从立方体、球体变为星形等
pfn["SuperEllipsoid"].SetN1(0.5)
pfn["SuperEllipsoid"].SetN2(0.4)
# 调整超环面的参数 N1 和 N2，可以改变其横截面和主体的形状
pfn["SuperToroid"].SetN1(0.5)
pfn["SuperToroid"].SetN2(3.0)
# The spline needs points
spline_points = vtkPoints()
rng = vtkMinimalStandardRandomSequence()
rng.SetSeed(8775070)
for p in range(0, 10):
xyz = [None] * 3
for idx in range(0, len(xyz)):
xyz[idx] = rng.GetRangeValue(-1.0, 1.0)
rng.Next()
spline_points.InsertNextPoint(xyz)
pfn["Spline"].SetPoints(spline_points)
# 设置波西米亚圆顶的参数 A、B 和 C。这些参数控制了圆顶的形状和复杂性
pfn["BohemianDome"].SetA(5.0)
pfn["BohemianDome"].SetB(1.0)
pfn["BohemianDome"].SetC(2.0)
# 设置库恩曲面的一个参数，通常用于调整曲面在奇异点附近的平滑度
pfn["Kuen"].SetDeltaV0(0.001)
return pfn
def get_centre(bounds):
"""
Get the centre of the object from the bounding box.
:param bounds: The bounding box of the object.
:return:
"""
if len(bounds) != 6:
return None
return [bounds[i] - (bounds[i] - bounds[i - 1]) / 2.0 for i in range(1, len(bounds), 2)]
def get_maximum_length(bounds):
"""
Calculate the maximum length of the side bounding box.
:param bounds: The bounding box of the object.
:return:
"""
if len(bounds) != 6:
return None
return max([bounds[i] - bounds[i - 1] for i in range(1, len(bounds), 2)])
def display_bounding_box_and_center(name, bounds):
"""
Display the dimensions of the bounding box, maximum diagonal length
and coordinates of the centre.
:param name: The name of the object.
:param bounds: The bounding box of the object.
:return:
"""
if len(bounds) != 6:
return
max_len = get_maximum_length(bounds)
centre = get_centre(bounds)
s = '{:21s}\n'.format(name)
s += '{:21s}{:1s}'.format(' Bounds (min, max)', ':')
s += '{:s}({:6.2f}, {:6.2f})'.format(' x:', bounds[0], bounds[1])
s += '{:s}({:6.2f}, {:6.2f})'.format(' y:', bounds[2], bounds[3])
s += '{:s}({:6.2f}, {:6.2f})\n'.format(' z:', bounds[4], bounds[5])
if max_len:
s += ' Maximum side length: {:6.2f}\n'.format(max_len)
if centre:
s += ' Centre (x, y, z) : ({:6.2f}, {:6.2f}, {:6.2f})\n'.format(centre[0], centre[1], centre[2])
print(s)
class PrintCallback:
def __init__(self, caller, file_name, image_quality=1, rgba=True):
self.caller = caller
self.image_quality = image_quality
# rgba is the the buffer type,
# (if true, there is no background in the screenshot).
self.rgba = rgba
parent = Path(file_name).resolve().parent
pth = Path(parent) / file_name
self.path = Path(str(pth)).with_suffix('.png')
def __call__(self, caller, ev):
# Save the screenshot.
if caller.GetKeyCode() == "k":
w2if = vtkWindowToImageFilter()
w2if.SetInput(caller.GetRenderWindow())
w2if.SetScale(self.image_quality, self.image_quality)
if self.rgba:
w2if.SetInputBufferTypeToRGBA()
else:
w2if.SetInputBufferTypeToRGB()
# Read from the front buffer.
w2if.ReadFrontBufferOn()
w2if.Update()
writer = vtkPNGWriter()
writer.SetFileName(self.path)
writer.SetInputData(w2if.GetOutput())
writer.Write()
print('Screenshot saved to:', self.path.name)
if __name__ == '__main__':
main()