vtk c++ 从 contourfilter 更新轮廓
vtk c++ update contour from contourfilter
我有一个渲染的 3D .vtk 模型，我使用 vtkContourFilter 从生成的图像中提取轮廓（在 Ubuntu 16.04 上使用 vtk 版本 7.0.0）。
我想从不同的角度投影它，但是当我遍历不同的相机位置时（我检查相机位置确实发生了变化）每次迭代启动的交互式查看器总是显示第一个的轮廓图片。
当我输出找到的轮廓点的前几个坐标（我将其存储为 vtkPolyData）时，我还注意到我的轮廓点集中的内容没有改变。
我尝试了一些对其他人有用的在线建议，例如添加：
ContFilter->Modified();
ContFilter->Update();
和
polyData->Modified(); // This is the 3D vtkPolyData that I project
和
ContFilter->SetValue(0, 10);
ContFilter->SetValue(0, 255);
作为一个疯狂的猜测，我也尝试添加：
polyData->Modified();
// Remove old links
renderWindow->RemoveRenderer(renderer);
mapper->RemoveAllInputs();
// Set new links
renderer->SetActiveCamera(camera);
renderWindow->AddRenderer(renderer);
renderer->Modified();
renderer->ResetCameraClippingRange();
renderWindow->Modified();
mapper->SetInputData(polyData);
renderWindow->Render();
在 for 循环中，在使用 ContourFilter 之前，但它仍然没有更新。有了这个，我尝试了所有我能想到的和在网上找到的东西。
这是相关代码：
// Prepare the rendering environment to project the 3D model to an image from different perspectives
vtkSmartPointer<vtkDataSetMapper> mapper = vtkSmartPointer<vtkDataSetMapper>::New();
mapper->SetInputData(polyData);
mapper->ScalarVisibilityOff();
vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
actor->GetProperty()->SetInterpolationToFlat();
vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
renderer->SetBackground(1,1,1);
renderer->AddActor(actor);
vtkSmartPointer<vtkCamera> camera = vtkSmartPointer<vtkCamera>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->SetOffScreenRendering(1);
vtkSmartPointer<vtkWindowToImageFilter> windowToImageFilter = vtkSmartPointer<vtkWindowToImageFilter>::New();
vtkSmartPointer<vtkContourFilter> ContFilter = vtkSmartPointer<vtkContourFilter>::New();
vtkSmartPointer<vtkPolyData> contour = vtkSmartPointer<vtkPolyData>::New();
// Loop over the camera positions. At each iteration render/project,
// extract the contour and finally render the 3D model and the found
// contour
double * iPoint;
double * camPos;
double * contourStart;
int nContours;
for(int i=0; i<positions->GetNumberOfPoints(); i++){
// Print the camera position
iPoint = positions->GetPoint(i);
std::cout << iPoint[0] << " " << iPoint[1] << " " << iPoint[2] << std::endl;
//Move camera
camera->SetPosition(iPoint[0], iPoint[1], iPoint[2]);
camera->SetFocalPoint(focalPointOrig[0], focalPointOrig[1], focalPointOrig[2]);
camera->SetViewAngle(viewAngle);
camera->Modified();
camera->SetRoll(90);
// Does this help to update the view?
polyData->Modified();
// Remove old links and set them again
renderWindow->RemoveRenderer(renderer);
mapper->RemoveAllInputs();
renderer->SetActiveCamera(camera);
renderWindow->AddRenderer(renderer);
renderer->Modified();
renderer->ResetCameraClippingRange();
renderWindow->Modified();
// Render/project the data
mapper->SetInputData(polyData);
renderWindow->Render();
// Print camera position for debugging
camera->GetPosition(camPos);
std::cout << camPos[0] << " " << camPos[1] << " " << camPos[2] << std::endl;
// Get the image and apply a contourfilter
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
ContFilter->SetInputConnection(windowToImageFilter->GetOutputPort());
// Saw someone do this as a workaround for updating the view
ContFilter->SetValue(0, 10);
ContFilter->SetValue(0, 255);
// Does this help to update the view?
ContFilter->Modified();
//Get the contour from the contourfilter
ContFilter->Update();
contour = ContFilter->GetOutput();
// Print the first points coordinates to see if they changed
contourStart = contour->GetPoint(1);
std::cout << contourStart[0] << " " << contourStart[1] << " " << std::endl;
// Print the number of contours to see if it may be stored as an additional contour
nContours = ContFilter->GetNumberOfContours();
std::cout << nContours << std::endl;
// Render the 3D model and the found contour
actor->GetProperty()->SetColor(0.9,0.9,0.8);
// Create a mapper and actor of the silhouette
vtkSmartPointer<vtkPolyDataMapper> mapper_contour = vtkSmartPointer<vtkPolyDataMapper>::New();
mapper_contour->SetInputData(contour);
// Try this again here
polyData->Modified();
vtkSmartPointer<vtkActor> actor_contour = vtkSmartPointer<vtkActor>::New();
actor_contour->SetMapper(mapper_contour);
actor_contour->GetProperty()->SetLineWidth(2.);
// 2 renderers and a render window
vtkSmartPointer<vtkRenderer> renderer1 = vtkSmartPointer<vtkRenderer>::New();
renderer1->AddActor(actor);
vtkSmartPointer<vtkRenderer> renderer2 = vtkSmartPointer<vtkRenderer>::New();
renderer2->AddActor(actor_contour);
// Set the 3D model renderer to the same perspective but don't change the camera perspective of the contour
renderer1->SetActiveCamera(camera);
// Setup the window
vtkSmartPointer<vtkRenderWindow> renderwindow = vtkSmartPointer<vtkRenderWindow>::New();
renderwindow->SetSize(1600, 800);
renderwindow->AddRenderer(renderer1);
renderer1->SetViewport(0., 0., 0.5, 1.);
renderwindow->AddRenderer(renderer2);
renderer2->SetViewport(0.5, 0., 1., 1.);
// Setup the interactor
vtkSmartPointer<vtkInteractorStyleTrackballCamera> style = vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
vtkSmartPointer<vtkRenderWindowInteractor> iren = vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow( renderwindow);
iren->SetInteractorStyle(style);
// Display the coordinate system axes
vtkSmartPointer<vtkAxesActor> axes = vtkSmartPointer<vtkAxesActor>::New();
vtkSmartPointer<vtkOrientationMarkerWidget> widget = vtkSmartPointer<vtkOrientationMarkerWidget>::New();
widget->SetOutlineColor( 0.9300, 0.5700, 0.1300 );
widget->SetOrientationMarker( axes );
widget->SetInteractor( iren );
widget->SetViewport( 0.0, 0.0, 0.4, 0.4 );
widget->SetEnabled( 1 );
widget->InteractiveOn();
// Render the 3D model and the found contour
renderwindow->Render();
iren->Start();
}
刚刚找到答案。
如 vtkWindowToImageFilter class 参考网页 (https://www.vtk.org/doc/nightly/html/classvtkWindowToImageFilter.html) 的详细说明中的警告中所述，vtkWindows 通常不会重新呈现，除非您调用他们的 Modified()函数。现在，我的投影视图已按我想要的方式更新。
所以我改变了
// Get the image and apply a contourfilter
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
至
// Get the image and apply a contourfilter
windowToImageFilter->Modified();
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
如果上面的 link 停止工作，请在此处查看警告文本：
Warning:
A vtkWindow doesn't behave like other parts of the VTK pipeline: its modification time doesn't get updated when an image is rendered. As a result, naive use of vtkWindowToImageFilter will produce an image of the first image that the window rendered, but which is never updated on subsequent window updates. This behavior is unexpected and in general undesirable.
To force an update of the output image, call vtkWindowToImageFilter's Modified method after rendering to the window.
In VTK versions 4 and later, this filter is part of the canonical way to output an image of a window to a file (replacing the obsolete SaveImageAsPPM method for vtkRenderWindows that existed in 3.2 and earlier). Connect this filter to the output of the window, and filter's output to a writer such as vtkPNGWriter.
Reading back alpha planes is dependent on the correct operation of the render window's GetRGBACharPixelData method, which in turn is dependent on the configuration of the window's alpha planes. As of VTK 4.4+, machine-independent behavior is not automatically assured because of these dependencies.
我有一个渲染的 3D .vtk 模型，我使用 vtkContourFilter 从生成的图像中提取轮廓（在 Ubuntu 16.04 上使用 vtk 版本 7.0.0）。
我想从不同的角度投影它，但是当我遍历不同的相机位置时（我检查相机位置确实发生了变化）每次迭代启动的交互式查看器总是显示第一个的轮廓图片。
当我输出找到的轮廓点的前几个坐标（我将其存储为 vtkPolyData）时，我还注意到我的轮廓点集中的内容没有改变。
我尝试了一些对其他人有用的在线建议，例如添加：
ContFilter->Modified();
ContFilter->Update();
和
polyData->Modified(); // This is the 3D vtkPolyData that I project
和
ContFilter->SetValue(0, 10);
ContFilter->SetValue(0, 255);
作为一个疯狂的猜测，我也尝试添加：
polyData->Modified();
// Remove old links
renderWindow->RemoveRenderer(renderer);
mapper->RemoveAllInputs();
// Set new links
renderer->SetActiveCamera(camera);
renderWindow->AddRenderer(renderer);
renderer->Modified();
renderer->ResetCameraClippingRange();
renderWindow->Modified();
mapper->SetInputData(polyData);
renderWindow->Render();
在 for 循环中，在使用 ContourFilter 之前，但它仍然没有更新。有了这个，我尝试了所有我能想到的和在网上找到的东西。
这是相关代码：
// Prepare the rendering environment to project the 3D model to an image from different perspectives
vtkSmartPointer<vtkDataSetMapper> mapper = vtkSmartPointer<vtkDataSetMapper>::New();
mapper->SetInputData(polyData);
mapper->ScalarVisibilityOff();
vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
actor->GetProperty()->SetInterpolationToFlat();
vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
renderer->SetBackground(1,1,1);
renderer->AddActor(actor);
vtkSmartPointer<vtkCamera> camera = vtkSmartPointer<vtkCamera>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->SetOffScreenRendering(1);
vtkSmartPointer<vtkWindowToImageFilter> windowToImageFilter = vtkSmartPointer<vtkWindowToImageFilter>::New();
vtkSmartPointer<vtkContourFilter> ContFilter = vtkSmartPointer<vtkContourFilter>::New();
vtkSmartPointer<vtkPolyData> contour = vtkSmartPointer<vtkPolyData>::New();
// Loop over the camera positions. At each iteration render/project,
// extract the contour and finally render the 3D model and the found
// contour
double * iPoint;
double * camPos;
double * contourStart;
int nContours;
for(int i=0; i<positions->GetNumberOfPoints(); i++){
// Print the camera position
iPoint = positions->GetPoint(i);
std::cout << iPoint[0] << " " << iPoint[1] << " " << iPoint[2] << std::endl;
//Move camera
camera->SetPosition(iPoint[0], iPoint[1], iPoint[2]);
camera->SetFocalPoint(focalPointOrig[0], focalPointOrig[1], focalPointOrig[2]);
camera->SetViewAngle(viewAngle);
camera->Modified();
camera->SetRoll(90);
// Does this help to update the view?
polyData->Modified();
// Remove old links and set them again
renderWindow->RemoveRenderer(renderer);
mapper->RemoveAllInputs();
renderer->SetActiveCamera(camera);
renderWindow->AddRenderer(renderer);
renderer->Modified();
renderer->ResetCameraClippingRange();
renderWindow->Modified();
// Render/project the data
mapper->SetInputData(polyData);
renderWindow->Render();
// Print camera position for debugging
camera->GetPosition(camPos);
std::cout << camPos[0] << " " << camPos[1] << " " << camPos[2] << std::endl;
// Get the image and apply a contourfilter
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
ContFilter->SetInputConnection(windowToImageFilter->GetOutputPort());
// Saw someone do this as a workaround for updating the view
ContFilter->SetValue(0, 10);
ContFilter->SetValue(0, 255);
// Does this help to update the view?
ContFilter->Modified();
//Get the contour from the contourfilter
ContFilter->Update();
contour = ContFilter->GetOutput();
// Print the first points coordinates to see if they changed
contourStart = contour->GetPoint(1);
std::cout << contourStart[0] << " " << contourStart[1] << " " << std::endl;
// Print the number of contours to see if it may be stored as an additional contour
nContours = ContFilter->GetNumberOfContours();
std::cout << nContours << std::endl;
// Render the 3D model and the found contour
actor->GetProperty()->SetColor(0.9,0.9,0.8);
// Create a mapper and actor of the silhouette
vtkSmartPointer<vtkPolyDataMapper> mapper_contour = vtkSmartPointer<vtkPolyDataMapper>::New();
mapper_contour->SetInputData(contour);
// Try this again here
polyData->Modified();
vtkSmartPointer<vtkActor> actor_contour = vtkSmartPointer<vtkActor>::New();
actor_contour->SetMapper(mapper_contour);
actor_contour->GetProperty()->SetLineWidth(2.);
// 2 renderers and a render window
vtkSmartPointer<vtkRenderer> renderer1 = vtkSmartPointer<vtkRenderer>::New();
renderer1->AddActor(actor);
vtkSmartPointer<vtkRenderer> renderer2 = vtkSmartPointer<vtkRenderer>::New();
renderer2->AddActor(actor_contour);
// Set the 3D model renderer to the same perspective but don't change the camera perspective of the contour
renderer1->SetActiveCamera(camera);
// Setup the window
vtkSmartPointer<vtkRenderWindow> renderwindow = vtkSmartPointer<vtkRenderWindow>::New();
renderwindow->SetSize(1600, 800);
renderwindow->AddRenderer(renderer1);
renderer1->SetViewport(0., 0., 0.5, 1.);
renderwindow->AddRenderer(renderer2);
renderer2->SetViewport(0.5, 0., 1., 1.);
// Setup the interactor
vtkSmartPointer<vtkInteractorStyleTrackballCamera> style = vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
vtkSmartPointer<vtkRenderWindowInteractor> iren = vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow( renderwindow);
iren->SetInteractorStyle(style);
// Display the coordinate system axes
vtkSmartPointer<vtkAxesActor> axes = vtkSmartPointer<vtkAxesActor>::New();
vtkSmartPointer<vtkOrientationMarkerWidget> widget = vtkSmartPointer<vtkOrientationMarkerWidget>::New();
widget->SetOutlineColor( 0.9300, 0.5700, 0.1300 );
widget->SetOrientationMarker( axes );
widget->SetInteractor( iren );
widget->SetViewport( 0.0, 0.0, 0.4, 0.4 );
widget->SetEnabled( 1 );
widget->InteractiveOn();
// Render the 3D model and the found contour
renderwindow->Render();
iren->Start();
}
刚刚找到答案。
如 vtkWindowToImageFilter class 参考网页 (https://www.vtk.org/doc/nightly/html/classvtkWindowToImageFilter.html) 的详细说明中的警告中所述，vtkWindows 通常不会重新呈现，除非您调用他们的 Modified()函数。现在，我的投影视图已按我想要的方式更新。
所以我改变了
// Get the image and apply a contourfilter
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
至
// Get the image and apply a contourfilter
windowToImageFilter->Modified();
windowToImageFilter->SetInput(renderWindow);
windowToImageFilter->Update();
如果上面的 link 停止工作，请在此处查看警告文本：
Warning: A vtkWindow doesn't behave like other parts of the VTK pipeline: its modification time doesn't get updated when an image is rendered. As a result, naive use of vtkWindowToImageFilter will produce an image of the first image that the window rendered, but which is never updated on subsequent window updates. This behavior is unexpected and in general undesirable. To force an update of the output image, call vtkWindowToImageFilter's Modified method after rendering to the window. In VTK versions 4 and later, this filter is part of the canonical way to output an image of a window to a file (replacing the obsolete SaveImageAsPPM method for vtkRenderWindows that existed in 3.2 and earlier). Connect this filter to the output of the window, and filter's output to a writer such as vtkPNGWriter. Reading back alpha planes is dependent on the correct operation of the render window's GetRGBACharPixelData method, which in turn is dependent on the configuration of the window's alpha planes. As of VTK 4.4+, machine-independent behavior is not automatically assured because of these dependencies.