用vtkLineWidget2显示一条线，结果只有一个黑框框，没有显示出来线。

代码如下：
#include "vtkLineWidget2.h"
#include "vtkSmartPointer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkLineRepresentation.h"
int main( int argc, char** argv )
{
vtkSmartPointer<vtkLineRepresentation> pRepresent = vtkSmartPointer<vtkLineRepresentation>::New();
double dPos1[3] = { 10, 0, 0 };
double dPos2[3] = { 50, 30, 0 };
pRepresent->SetPoint1WorldPosition( dPos1 );
pRepresent->SetPoint2WorldPosition( dPos2 );
pRepresent->SetLineColor( 0, 1, 0 );
vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
interactor->SetRenderWindow( renderWindow );
vtkSmartPointer<vtkLineWidget2> lineWidget = vtkSmartPointer<vtkLineWidget2>::New();
lineWidget->SetInteractor( interactor );
lineWidget->SetRepresentation( pRepresent );
lineWidget->On();
interactor->Initialize();
interactor->Start();
return 0;
}

结果如下：

vtkLineSource

vtkLine 也行

vtkSmartPointer<vtkLineWidget2> lineWidget = vtkSmartPointer<vtkLineWidget2>::New();
lineWidget->SetInteractor(renderWindowInteractor);
lineWidget->CreateDefaultRepresentation();//少了这个？