Qt使用VTK遇到的一些问题

一、vtkOrientationMarkerWidget在Qt窗口中不显示

1. 注意this->setRenderWindow(renderWindow);和this->renderWindow()->AddRenderer(renderer);以及omw->EnabledOn();代码段的位置

2. vtkOrientationMarkerWidget不要在局部使用智能指针，出了作用域会被析构

点击查看代码

/*VTKWidget继承自QVTKRenderWidget*/
VTKWidget::VTKWidget()
{
        vtkNew<vtkNamedColors> colors;

	vtkNew<vtkGenericOpenGLRenderWindow> renderWindow;
	this->setRenderWindow(renderWindow);

	vtkNew<vtkInteractorStyleRubberBand3D> style;
	this->interactor()->SetInteractorStyle(style);

	// Sphere
	vtkNew<vtkSphereSource> sphereSource;
	sphereSource->Update();
	vtkNew<vtkPolyDataMapper> sphereMapper;
	sphereMapper->SetInputConnection(sphereSource->GetOutputPort());
	vtkNew<vtkActor> sphereActor;
	sphereActor->SetMapper(sphereMapper);
	sphereActor->GetProperty()->SetColor(colors->GetColor4d("Tomato").GetData());

	// VTK Renderer
	vtkNew<vtkRenderer> renderer;
	renderer->AddActor(sphereActor);
	renderer->SetBackground(colors->GetColor3d("SteelBlue").GetData());
	renderer->ResetCamera();

	// Connect VTK with Qt
	this->renderWindow()->AddRenderer(renderer);

	std::array<double, 3> scale{ {1.0, 1.0, 1.0} };

	vtkAxesActor* axes = vtkAxesActor::New();
	axes->SetScale(1,1,1);
	axes->SetShaftTypeToCylinder();

	axes->SetCylinderRadius(0.5 * axes->GetCylinderRadius());  //轴的粗细
	axes->SetConeRadius(1.025 * axes->GetConeRadius());        //圆锥的大小
	axes->SetSphereRadius(1.5 * axes->GetSphereRadius());

	vtkTextProperty* tprop = axes->GetXAxisCaptionActor2D()->GetCaptionTextProperty();
	tprop->ItalicOn();  //启用文本斜体
	tprop->ShadowOn();  //启用文本阴影
	tprop->SetFontFamilyToTimes();  //字体
	tprop->SetColor(1, 1, 1);  //标签文字颜色

	axes->GetYAxisCaptionActor2D()->GetCaptionTextProperty()->ShallowCopy(tprop);
	axes->GetZAxisCaptionActor2D()->GetCaptionTextProperty()->ShallowCopy(tprop);

        // 将omw声明为成员变量
	vtkOrientationMarkerWidget* omw = vtkOrientationMarkerWidget::New();
	omw->SetOrientationMarker(axes);
	omw->SetViewport(0.8, 0, 1.0, 0.2);
	omw->SetOutlineColor(1, 0, 0);
	omw->SetInteractor(this->interactor());
	omw->EnabledOn();
	omw->InteractiveOn();
}

二、Qt中使用VTK，渲染窗口背景颜色闪烁，图元不显示

1. 背景颜色闪烁是因为直接调用了renderer->Render();

2. 图元不显示是因为没有调用renderer->GetRenderWindow()->Render();

点击查看代码

/*this 继承自QVTKRenderWidget*/
	//renderer
	vtkNew<vtkRenderer> renderer;
	renderer->SetBackground(.1，.2，.3);
	renderer->AddActor(cubeActor);
	renderer->SetActiveCamera(camera);
	renderer->ResetCamera();

	//RenderWindow
	vtkNew<vtkGenericOpenGLRenderWindow> renWin;
	renWin->AddRenderer(renderer);

	this->setRenderWindow(renWin);
	//renderer->Render();  //调用该函数会导致窗口背景闪烁，甚至程序崩溃，可以使用下面的接口解决
	renderer->GetRenderWindow()->Render();

三、云图只显示一种颜色

检查mapper是否设置了range 即 vtkPolyDataMapper->SetScalarRange(range);

四、报错："static_cast":无法从"vtkObjectBase* const"转换为"T*"

只有类的前置声明，没有实际包含头文件，一般发生在头文件中定义函数，但只声明了vtk类

五、中断："Cannot make QOpenGLContext current in a different thread"

同一个上下文不能在多个线程中使用，报该错误的原因是因为在不同线程调用了vtk的Render()函数，保证在同一个线程调用Render即可解决。