Qt&Vtk-007-Cone2

Posted 2021-09-04 DreamLife.

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文章目录

Qt&Vtk-Cone2

Qt&Vtk-Cone2

今天我们又来搬运代码了，看标题也知道，这个和昨天的那个应该是没有啥区别的，那么我看官方实例的描述的，就是下面的内容。

// This example shows how to add an observer to a C++ program. It extends
// the Step1/Cxx/Cone.cxx C++ example (see that example for information on
// the basic setup).

大致翻译：意思就是演示一下如何在C++中添加一个观察者，项目是扩展的了昨天的那个Cone

官方的效果呢，就是下面这个鬼样子，相比于昨天的样子，就是在cmd窗口中有了数据输出。

1 代码搬运

1.1 cone2.h

#ifndef CONE2_H
#define CONE2_H

#include <QWidget>
#include <QTimer>
#include <QDebug>
#include <QString>
#include <QTextBrowser>
#include "QVTKOpenGLWidget.h"               //新版本，旧版QVTKWidget
#include "vtkAutoInit.h"
#include "vtkConeSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkRenderWindow.h"
#include "vtkCamera.h"
#include "vtkActor.h"
#include "vtkRenderer.h"
#include "vtkCommand.h"
namespace Ui {
class Cone2;
}
class vtkMyCallback : public vtkCommand
{
public:
    static vtkMyCallback *New()
    {
        return new vtkMyCallback;
    }
    void Execute(vtkObject *caller,unsigned long,void*) override;
    QTextBrowser *textBrowser = nullptr;
private:
};
class Cone2 : public QWidget
{
    Q_OBJECT
public:
    explicit Cone2(QWidget *parent = nullptr);
    ~Cone2();
    void outputMessage(double temp);

private:
    Ui::Cone2 *ui;
    vtkConeSource *cone = nullptr;                  //声明椎体
    vtkPolyDataMapper *coneMapper = nullptr;        //声明映射器
    vtkActor *coneActor = nullptr;                  //声明Actor
    vtkRenderer *coneRender = nullptr;              //声明渲染器
    QTimer *rotationTimer = nullptr;                //声明定时器，用于旋转椎体
    vtkMyCallback *myCallBack = nullptr;
};

#endif // CONE2_H

1.2 cone2.cpp

#include "cone2.h"
#include "ui_cone2.h"

Cone2::Cone2(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Cone2)
{
    ui->setupUi(this);
    cone = vtkConeSource::New();    //新建对象

    cone->SetHeight(3.0);           //设置高度
    cone->SetRadius(1.0);           //设置半径
    cone->SetResolution(10000000);        //翻译为设置分辨率，不过实际应该不是

    coneMapper = vtkPolyDataMapper::New();          //新建映射器
    coneMapper->SetInputConnection(cone->GetOutputPort());  //设置Cone输出coneMapper数据输入

    //新建Actor，并设置映射器
    coneActor = vtkActor::New();
    coneActor->SetMapper(coneMapper);
    //新建渲染器并设置Actor和背景颜色
    coneRender = vtkRenderer::New();
    coneRender->AddActor(coneActor);
    coneRender->SetBackground(0.1,0.2,0.3);

    myCallBack = vtkMyCallback::New();
    myCallBack->textBrowser = ui->textBrowser;
    coneRender->AddObserver(vtkCommand::StartEvent,myCallBack);

    //获取渲染窗口
    ui->widget->GetRenderWindow()->AddRenderer(coneRender);


    //    while (1) {
    //        ui->widget->GetRenderWindow()->Render();
    //        coneRender->GetActiveCamera()->Azimuth(1);
    //    }
    //旋转椎体
    rotationTimer = new QTimer();
    connect(rotationTimer,&QTimer::timeout,this,[=](){
        coneRender->GetActiveCamera()->Azimuth(1);
        ui->widget->GetRenderWindow()->Render();            //注意这句话，要加上呀，不然人不给你转，惰性渲染。
    });

    rotationTimer->start(25);
}

Cone2::~Cone2()
{
    rotationTimer->stop();
    delete ui;
}
void vtkMyCallback::Execute(vtkObject *caller, unsigned long, void *)
{
    vtkRenderer *renderer = reinterpret_cast<vtkRenderer*>(caller);
    textBrowser->append("Camera Position:");
    textBrowser->append(QString::number((renderer->GetActiveCamera()->GetPosition()[0]),'g',6));
    textBrowser->append(QString::number((renderer->GetActiveCamera()->GetPosition()[1]),'g',6));
    textBrowser->append(QString::number((renderer->GetActiveCamera()->GetPosition()[2]),'g',6));
}

1.3 官方代码

#include "vtkConeSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkRenderWindow.h"
#include "vtkCommand.h"
#include "vtkCamera.h"
#include "vtkActor.h"
#include "vtkRenderer.h"

// Callback for the interaction
class vtkMyCallback : public vtkCommand
{
public:
  static vtkMyCallback *New()
    { return new vtkMyCallback; }
  void Execute(vtkObject *caller, unsigned long, void*) override
  {
      vtkRenderer *renderer = reinterpret_cast<vtkRenderer*>(caller);
      cout << renderer->GetActiveCamera()->GetPosition()[0] << " "
           << renderer->GetActiveCamera()->GetPosition()[1] << " "
           << renderer->GetActiveCamera()->GetPosition()[2] << "\\n";
  }
};

int main()
{
  //
  // The pipeline creation is documented in Step1
  //
  vtkConeSource *cone = vtkConeSource::New();
  cone->SetHeight( 3.0 );
  cone->SetRadius( 1.0 );
  cone->SetResolution( 10 );

  vtkPolyDataMapper *coneMapper = vtkPolyDataMapper::New();
  coneMapper->SetInputConnection( cone->GetOutputPort() );
  vtkActor *coneActor = vtkActor::New();
  coneActor->SetMapper( coneMapper );

  vtkRenderer *ren1= vtkRenderer::New();
  ren1->AddActor( coneActor );
  ren1->SetBackground( 0.1, 0.2, 0.4 );
  ren1->ResetCamera();

  vtkRenderWindow *renWin = vtkRenderWindow::New();
  renWin->AddRenderer( ren1 );
  renWin->SetSize( 300, 300 );

  // Here is where we setup the observer, we do a new and ren1 will
  // eventually free the observer
  vtkMyCallback *mo1 = vtkMyCallback::New();
  ren1->AddObserver(vtkCommand::StartEvent,mo1);
  mo1->Delete();

  //
  // now we loop over 360 degrees and render the cone each time
  //
  int i;
  for (i = 0; i < 360; ++i)
  {
    // render the image
    renWin->Render();
    // rotate the active camera by one degree
    ren1->GetActiveCamera()->Azimuth( 1 );
  }

  //
  // Free up any objects we created
  //
  cone->Delete();
  coneMapper->Delete();
  coneActor->Delete();
  ren1->Delete();
  renWin->Delete();

  return 0;
}

2 运行效果

在第1.3 中之所以贴出了官方的代码，就是为了让大家看下原生的内容，我这里做了改动，就是把他的输出信息显示到我界面的一个TextBrowser中了。

3 知识点

3.1 观察者模式

参考资料：https://zhuanlan.zhihu.com/p/119308881

https://blog.csdn.net/hyongilfmmm/article/details/83015045?utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromMachineLearnPai2%7Edefault-4.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromMachineLearnPai2%7Edefault-4.control

引用资料中的一句话观察者模式的核心思想就是一对多。

看到这里，是不是感觉和Qt 的信号槽好像呀，Qt的信号槽就是观察者模式的一种实现。