如何告诉VTK管道使用通过TimerEvent更新的新vtkPolyData?

问题是单元格不是通过指针存储的 - 当你调用cells->InsertNextCell(polyLine);时，数据被复制，而不是指向，以便创建数组中单元格的有效存储(整个实现实际上在vtkCellArray的标头中，因此您可以检查出来(。因此，当您更新 polyLine 时，它在 polydata 中不起作用，因为 polydata 有自己的副本，而您没有更新。以下代码对我有用(你必须公开polydata和cellArray(：

virtual void Execute(vtkObject *vtkNotUsed(caller), unsigned long eventId,
void *vtkNotUsed(callData))
{
if (vtkCommand::TimerEvent == eventId)
{
NextPoint(); // Add another point to polyData
cells->Initialize(); // reset the cells to remove the old spiral
cells->InsertNextCell(polyLine); // re-insert the updated spiral
cells->Modified(); // required to update
data->Modified(); // required to update
++this->TimerCount;
cout << polyLine->GetNumberOfPoints() << endl;
renderWindow->Render(); // refresh the render window after each update
}
}

昨天我使用 vtkProgrammableDataObjectSource 作为数据源制定了一个替代解决方案。Tomj的解决方案是更直接，更简单的解决方案...但是，vtk.org 没有C++示例代码来解释如何使用vtkProgrammableDataObjectSource，我必须通过反复试验来解决。所以我会把它贴在这里，因为它可能会帮助其他人：

#include <vtkAutoInit.h>
VTK_MODULE_INIT(vtkRenderingOpenGL2);
VTK_MODULE_INIT(vtkRenderingContextOpenGL2);
VTK_MODULE_INIT(vtkRenderingVolumeOpenGL2);
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingFreeType);
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkConeSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkPoints.h>
#include <vtkPolyLine.h>
#include <vtkProgrammableFilter.h>
#include <vtkCallbackCommand.h>
#include <vtkPolyDataStreamer.h>
#include <vtkProgrammableDataObjectSource.h>

vtkSmartPointer<vtkProgrammableDataObjectSource> pDOS = vtkSmartPointer<vtkProgrammableDataObjectSource>::New();
vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
vtkSmartPointer<vtkPolyLine> polyLine = vtkSmartPointer<vtkPolyLine>::New();
int numOfPoints = 0;
double t = 0;
void NextPoint() {
double x = t * cos(t);
double y = t * sin(t);
points->InsertNextPoint(x, y, t);
polyLine->GetPointIds()->InsertNextId(numOfPoints);
numOfPoints++;
t += 0.1;
}
void generateEllipse(void *caller) {
vtkProgrammableDataObjectSource *pDOS = vtkProgrammableDataObjectSource::SafeDownCast((vtkObjectBase*)caller);
vtkSmartPointer<vtkCellArray> cells = vtkSmartPointer<vtkCellArray>::New();
cells->InsertNextCell(polyLine);
vtkSmartPointer<vtkPolyData> polyData = vtkSmartPointer<vtkPolyData>::New();
polyData->SetPoints(points);
polyData->SetLines(cells);
pDOS->SetOutput(polyData);
}

int counter2 = 0;
void TimerCallbackFunction(vtkObject* caller, long unsigned int vtkNotUsed(eventId), void* clientData, void* vtkNotUsed(callData)) {
cout << "timer callback: " << counter2 << endl;
// To avoid globals we can implement this later... 
//  vtkSmartPointer<vtkProgrammableDataObjectSource> pDOS =
//      static_cast<vtkProgrammableDataObjectSource*>(clientData);
vtkRenderWindowInteractor *rwi =
static_cast<vtkRenderWindowInteractor*>(caller);
NextPoint();
pDOS->Modified();
rwi->Render();
renderer->ResetCamera(); // Optional: Reposition Camera, so it displays the whole object
counter2++;
}

int main(int argc, char** argv) {
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
vtkSmartPointer<vtkRenderWindowInteractor> rwi = vtkSmartPointer<vtkRenderWindowInteractor>::New();
rwi->SetRenderWindow(renderWindow);

pDOS->SetExecuteMethod(&generateEllipse, pDOS);
vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputConnection(pDOS->GetOutputPort());
vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
actor->GetProperty()->SetDiffuseColor(255, 255, 0);
renderWindow->AddRenderer(renderer);
renderer->AddActor(actor);
renderer->ResetCamera();
renderWindow->Render();
// Add Timer Event...
vtkSmartPointer<vtkCallbackCommand> timerCallback = vtkSmartPointer<vtkCallbackCommand>::New();
timerCallback->SetCallback(TimerCallbackFunction);
rwi->Initialize();
rwi->CreateRepeatingTimer(100);
rwi->AddObserver(vtkCommand::TimerEvent, timerCallback);

// Start Displaying...
rwi->Start();
return 0;
}