c++ - 在同一个 UI 中使用 QVTKWidget 和 QOpenGLWidget？

Question

我正在开发一个项目，该项目使用 QOpenGLWidget 的自定义子类来显示一些效果图。在 paintGL() 方法的末尾，它会调用小部件的 update() 方法来触发重绘事件(如果它可见)。现在我想向我的 Ui 添加一个额外的 QVTKWidget，我通过使用类似这样的东西来实现:

QVBoxLayout* layout = findChild<QVBoxLayout*>("layout_simulation");
QVTKWidget* widget = new QVTKWidget();

// Setup arrow
vtkSmartPointer<vtkArrowSource> arrowSource = vtkSmartPointer<vtkArrowSource>::New();

[more VTK stuff...]

widget->GetRenderWindow()->AddRenderer(renderer);
renderer->AddActor(arrowActor);
renderer->ResetCamera();

// Add widget to ui
layout->addWidget(widget);

VTK 小部件已添加到用户界面并按预期工作。问题是，一旦我使用 layout->addWidget() 方法，所有其他 QOpenGLWidget 对象就会变黑 并且不显示任何事物。此黑色也不是 VTKRenderer 的背景颜色，因为即使我更改了 VTK 小部件的背景颜色，其他小部件仍然是黑色。我检查了一下，paintGL() 仍然在循环中被调用，但它只是不显示任何内容。我很确定我没有在我的小部件子类中使用任何错误的 OpenGL 代码，所以我猜它与 QOpenGLWidget 和 QVTKWidget 的内部初始化有关。如果我省略所有 VTK 调用并仅添加新创建的 QVTKWidget，也会发生同样的情况。

有趣的是，如果我省略 layout->addWidget() 调用，VTK 在单独的窗口中打开渲染器，所有 OpenGL 小部件都可以正常工作。但我当然想将渲染器嵌入到我的用户界面中。

有没有人有这方面的经验，或者您知道我可能遇到的任何陷阱，或者是否有任何常见问题可能导致这种情况？

顺便说一句:我为我的 QOpenGLWidget 子类使用带有自定义着色器的 OpenGL 3.3 核心配置文件。

编辑:我删除了对 3.3 核心配置文件的请求，现在它使用 4.4 兼容性配置文件。我猜它现在使用与 VTKRenderer 相同的配置文件，因此可以排除这是错误的来源。

Answer 1

所以我不知道到底是什么导致了这个问题，但我解决了它。起初我发现 VTK 有第二个小部件类，称为 QVTKWidget2 但不幸的是它与 Qt 5.4 不完全兼容，因为它使用旧的 QGL 类(如 QGLWidget 而不是 QOpenGLWidget)。所以我开始将它重新实现为 QOpenGLWidget 的子类，这非常简单。下面是我的类 QVTKWidget3 的源文件，它适用于 Qt 5.4 供任何感兴趣的人使用。我只进行了有限的测试(因为我仍在学习 VTK)，但简单的示例(如显示球体)工作正常。

再说一次:这只适用于 Qt 5.4(测试版)，因为旧版本不提供 QOpenGLWidget 类!

头文件:qvtkwidget3.h

#ifndef QVTKWIDGET3_H
#define QVTKWIDGET3_H

#include "vtkSmartPointer.h"
#include "vtkGenericOpenGLRenderWindow.h"
#include "vtkEventQtSlotConnect.h"

#include "QVTKInteractorAdapter.h"
#include "QVTKInteractor.h"

#include <QOpenGLWidget>
#include <QSurfaceFormat>

class QVTKWidget3 : public QOpenGLWidget
{
    Q_OBJECT

public:
    QVTKWidget3(QWidget *parent = NULL, Qt::WindowFlags f = 0, QSurfaceFormat format = QSurfaceFormat::defaultFormat());
    virtual ~QVTKWidget3();

    //! Set a custom render window
    virtual void SetRenderWindow(vtkGenericOpenGLRenderWindow*);
    //! Returns the curren render window (creates one if none exists)
    virtual vtkGenericOpenGLRenderWindow* GetRenderWindow();

    //! Returns interactor of the current render window
    virtual QVTKInteractor* GetInteractor();

public slots:
    //! Slot to make this vtk render window current
    virtual void MakeCurrent();
    //! Slot called when vtk wants to know if the context is current
    virtual void IsCurrent(vtkObject* caller, unsigned long vtk_event, void* client_data, void* call_data);
    //! Slot called when vtk wants to frame the window
    virtual void Frame();
    //! Slot called when vtk wants to start the render
    virtual void Start();
    //! Slot called when vtk wants to end the render
    virtual void End();
    //! Slot called when vtk wants to know if a window is direct
    virtual void IsDirect(vtkObject* caller, unsigned long vtk_event, void* client_data, void* call_data);
    //! Slot called when vtk wants to know if a window supports OpenGL
    virtual void SupportsOpenGL(vtkObject* caller, unsigned long vtk_event, void* client_data, void* call_data);

protected:
    //! Initialize handler
    virtual void initializeGL();
    //! Paint handler
    virtual void paintGL();
    //! Resize handler
    virtual void resizeGL(int, int);
    //! Move handler
    virtual void moveEvent(QMoveEvent* event);

    virtual void mousePressEvent(QMouseEvent* event);
    virtual void mouseMoveEvent(QMouseEvent* event);
    virtual void mouseReleaseEvent(QMouseEvent* event);
    virtual void keyPressEvent(QKeyEvent* event);
    virtual void keyReleaseEvent(QKeyEvent* event);
    virtual void enterEvent(QEvent*);
    virtual void leaveEvent(QEvent*);
    virtual void wheelEvent(QWheelEvent*);

    virtual void contextMenuEvent(QContextMenuEvent*);
    virtual void dragEnterEvent(QDragEnterEvent*);
    virtual void dragMoveEvent(QDragMoveEvent*);
    virtual void dragLeaveEvent(QDragLeaveEvent*);
    virtual void dropEvent(QDropEvent*);

    virtual bool focusNextPrevChild(bool);

    // Members
    vtkGenericOpenGLRenderWindow* m_renWin;
    QVTKInteractorAdapter* m_irenAdapter;
    vtkSmartPointer<vtkEventQtSlotConnect> m_connect;

private:
    //! unimplemented operator=
    QVTKWidget3 const& operator=(QVTKWidget3 const&);
    //! unimplemented copy
    QVTKWidget3(const QVTKWidget3&);
};

#endif // QVTKWIDGET3_H

源文件:qvtkwidget3.cpp

#include "qvtkwidget3.h"

#include "vtkRenderWindowInteractor.h"
#include "vtkInteractorStyle.h"
#include "vtkInteractorStyleTrackballCamera.h"

#include <QResizeEvent>

QVTKWidget3::QVTKWidget3(QWidget *parent, Qt::WindowFlags f, QSurfaceFormat format)
    : QOpenGLWidget(parent, f)
    , m_renWin(nullptr)
{
    // VTK requires a compatibility profile
    format.setProfile(QSurfaceFormat::CompatibilityProfile);
    setFormat(format);

    // Initialize interactors
    m_irenAdapter = new QVTKInteractorAdapter(this);
    m_connect = vtkSmartPointer<vtkEventQtSlotConnect>::New();
}

// Destructor
QVTKWidget3::~QVTKWidget3()
{
  // Following line is not needed.
  // get rid of the VTK window
  // this->SetRenderWindow(NULL);
}

// GetRenderWindow
vtkGenericOpenGLRenderWindow* QVTKWidget3::GetRenderWindow()
{
    if (this->m_renWin == nullptr)
    {
        // create a default vtk window
        vtkGenericOpenGLRenderWindow* win = vtkGenericOpenGLRenderWindow::New();
        this->SetRenderWindow(win);
    }

    return this->m_renWin;
}

// SetRenderWindow
void QVTKWidget3::SetRenderWindow(vtkGenericOpenGLRenderWindow* w)
{
    // do nothing if we don't have to
    if(w == this->m_renWin) {
        return;
    }

    // unregister previous window
    if(this->m_renWin != nullptr) {
        this->m_renWin->Finalize();
        this->m_renWin->SetMapped(0);

        m_connect->Disconnect(m_renWin, vtkCommand::WindowMakeCurrentEvent, this, SLOT(MakeCurrent()));
        m_connect->Disconnect(m_renWin, vtkCommand::WindowIsCurrentEvent, this, SLOT(IsCurrent(vtkObject*, unsigned long, void*, void*)));
        m_connect->Disconnect(m_renWin, vtkCommand::WindowFrameEvent, this, SLOT(Frame()));
        m_connect->Disconnect(m_renWin, vtkCommand::StartEvent, this, SLOT(Start()));
        m_connect->Disconnect(m_renWin, vtkCommand::EndEvent, this, SLOT(End()));
        m_connect->Disconnect(m_renWin, vtkCommand::WindowIsDirectEvent, this, SLOT(IsDirect(vtkObject*, unsigned long, void*, void*)));
        m_connect->Disconnect(m_renWin, vtkCommand::WindowSupportsOpenGLEvent, this, SLOT(SupportsOpenGL(vtkObject*, unsigned long, void*, void*)));
    }

    // now set the window
    this->m_renWin = w;

    if(this->m_renWin != nullptr) {
        // if it is mapped somewhere else, unmap it
        this->m_renWin->Finalize();
        this->m_renWin->SetMapped(1);

        // tell the vtk window what the size of this window is
        this->m_renWin->SetSize(this->width(), this->height());
        this->m_renWin->SetPosition(this->x(), this->y());

        // if an interactor wasn't provided, we'll make one by default
        if(this->m_renWin->GetInteractor() == NULL)
        {
            // create a default interactor
            QVTKInteractor* iren = QVTKInteractor::New();
            iren->SetUseTDx(false);
            this->m_renWin->SetInteractor(iren);
            iren->Initialize();

            // now set the default style
            vtkInteractorStyle* s = vtkInteractorStyleTrackballCamera::New();
            iren->SetInteractorStyle(s);

            iren->Delete();
            s->Delete();
        }

        // tell the interactor the size of this window
        this->m_renWin->GetInteractor()->SetSize(this->width(), this->height());

        m_connect->Connect(m_renWin, vtkCommand::WindowMakeCurrentEvent, this, SLOT(MakeCurrent()));
        m_connect->Connect(m_renWin, vtkCommand::WindowIsCurrentEvent, this, SLOT(IsCurrent(vtkObject*, unsigned long, void*, void*)));
        m_connect->Connect(m_renWin, vtkCommand::WindowFrameEvent, this, SLOT(Frame()));
        m_connect->Connect(m_renWin, vtkCommand::StartEvent, this, SLOT(Start()));
        m_connect->Connect(m_renWin, vtkCommand::EndEvent, this, SLOT(End()));
        m_connect->Connect(m_renWin, vtkCommand::WindowIsDirectEvent, this, SLOT(IsDirect(vtkObject*, unsigned long, void*, void*)));
        m_connect->Connect(m_renWin, vtkCommand::WindowSupportsOpenGLEvent, this, SLOT(SupportsOpenGL(vtkObject*, unsigned long, void*, void*)));
    }
}

// GetInteractor
QVTKInteractor* QVTKWidget3::GetInteractor()
{
    return QVTKInteractor::SafeDownCast(this->GetRenderWindow()->GetInteractor());
}

// Initialize
void QVTKWidget3::initializeGL()
{
    if(this->m_renWin == nullptr) {
        return;
    }

    this->m_renWin->OpenGLInitContext();
}

// Paint
void QVTKWidget3::paintGL()
{
    vtkRenderWindowInteractor* iren = nullptr;
    if(this->m_renWin != nullptr) {
        iren = this->m_renWin->GetInteractor();
    }

    if(iren == nullptr || !iren->GetEnabled()) {
        return;
    }

    iren->Render();
}

// Resize
void QVTKWidget3::resizeGL(int w, int h)
{
    if(this->m_renWin == nullptr) {
        return;
    }

    this->m_renWin->SetSize(w,h);

    // and update the interactor
    if(this->m_renWin->GetInteractor() != NULL) {
        QResizeEvent e(QSize(w,h), QSize());
        m_irenAdapter->ProcessEvent(&e, this->m_renWin->GetInteractor());
    }
}

// Move
void QVTKWidget3::moveEvent(QMoveEvent* e)
{
    QWidget::moveEvent(e);

    if(this->m_renWin == nullptr) {
        return;
    }

    this->m_renWin->SetPosition(this->x(), this->y());
}


// --------
//  Slots
// --------

void QVTKWidget3::Start()
{
    makeCurrent();
    m_renWin->PushState();
    m_renWin->OpenGLInitState();
}

void QVTKWidget3::End()
{
    m_renWin->PopState();
}

void QVTKWidget3::MakeCurrent()
{
    return;
    // Automaticly handled by QOpenGLWidget
    // this->makeCurrent();
}

void QVTKWidget3::IsCurrent(vtkObject*, unsigned long, void*, void* call_data)
{
    bool* ptr = reinterpret_cast<bool*>(call_data);
    *ptr = (int)true;
}

void QVTKWidget3::IsDirect(vtkObject*, unsigned long, void*, void* call_data)
{
    int* ptr = reinterpret_cast<int*>(call_data);
    *ptr = (int)true;
}

void QVTKWidget3::SupportsOpenGL(vtkObject*, unsigned long, void*, void* call_data)
{
    int* ptr = reinterpret_cast<int*>(call_data);
    *ptr = (int)true;
}

void QVTKWidget3::Frame()
{
    if(m_renWin->GetSwapBuffers()) {
        this->update();
    }

    // This callback will call swapBuffers() for us
    // because sometimes VTK does a render without coming through this paintGL()

    // FOLLOWING NOT TESTED FOR QOPENGLWIDGET
    // if you want paintGL to always be called for each time VTK renders
    // 1. turn off EnableRender on the interactor,
    // 2. turn off SwapBuffers on the render window,
    // 3. add an observer for the RenderEvent coming from the interactor
    // 4. implement the callback on the observer to call updateGL() on this widget
    // 5. overload QVTKWidget3::paintGL() to call m_renWin->Render() instead iren->Render()
}

// ----------------------
//  Interaction handlers
// ----------------------

/*! handle mouse press event
 */
void QVTKWidget3::mousePressEvent(QMouseEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }

}

/*! handle mouse move event
 */
void QVTKWidget3::mouseMoveEvent(QMouseEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

/*! handle enter event
 */
void QVTKWidget3::enterEvent(QEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

/*! handle leave event
 */
void QVTKWidget3::leaveEvent(QEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

/*! handle mouse release event
 */
void QVTKWidget3::mouseReleaseEvent(QMouseEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

/*! handle key press event
 */
void QVTKWidget3::keyPressEvent(QKeyEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

/*! handle key release event
 */
void QVTKWidget3::keyReleaseEvent(QKeyEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::wheelEvent(QWheelEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::contextMenuEvent(QContextMenuEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::dragEnterEvent(QDragEnterEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::dragMoveEvent(QDragMoveEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::dragLeaveEvent(QDragLeaveEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

void QVTKWidget3::dropEvent(QDropEvent* e)
{
    if(this->m_renWin)
    {
        m_irenAdapter->ProcessEvent(e, this->m_renWin->GetInteractor());
    }
}

bool QVTKWidget3::focusNextPrevChild(bool)
{
    return false;
}