QT6+CloudCompare显示3D点云

    CloudCompare是一个三维点云（网格）编辑和处理软件。最初，它被设计用来对稠密的三维点云进行直接比较。它依赖于一种特定的八叉树结构，在进行点云对比这类任务时具有出色的性能。此外，由于大多数点云都是由地面激光扫描仪采集的，CloudCompare的目的是在一台标准笔记本电脑上处理大规模的点云——通常超过1000万个点云。在2005年后，cloudcompare就实现了点云和三角形网格之间的比较。随后，许多其他点云处理算法（配准、重采样、颜色/法线向量/尺度、统计计算、传感器管理、交互式或自动分割等）以及显示增强工具（自定义颜色渐变、颜色和法向量处理，校准图像处理、OpenGL着色器、插件等）

1 下载和安装

  CloudCompare软件的下载地址如下：

http://www.cloudcompare.org/

    源码地址如下：

https://github.com/cloudcompare/cloudcompare

2 构建Qt工程

 CloudCompare源码是基于Qt5的，如果你要编译Qt5版本，就直接用cmake编译就行。

    先构建如下的文件：

    CloudCompare.pro文件改为如下设置。

TEMPLATE    =   subdirs
SUBDIRS += \
            CC \
            contrib \
            libs \
            plugins \
            ccViewer
#            qCC \

 至于每个子项目的.pro怎么设置，可以参考如下代码：

TEMPLATE = lib
TARGET   = CC_CORE_LIB
CONFIG  += c++17
DEFINES += QT_DEPRECATED_WARNINGS
DEFINES += CC_CORE_LIB_EXPORTS

##################################################################
#指定生成的文件存放位置
##################################################################
MOC_DIR         = $$PWD/temp/moc
RCC_DIR         = $$PWD/temp/rcc
UI_DIR          = $$PWD/temp/ui
OBJECTS_DIR     = $$PWD/temp/obj
DESTDIR         = $$PWD/temp/bin

INCLUDEPATH +=  . \
                ./include \
                ./src

HEADERS += \
    include/AutoSegmentationTools.h \
    include/BoundingBox.h \
    include/CCConst.h \
    include/CCCoreLib.h \
    include/CCCoreLibExport.h \
    include/CCGeom.h \
    include/CCMiscTools.h \
    include/CCPlatform.h \
    include/CCShareable.h \
    include/CCToolbox.h \
    include/CCTypes.h \
    include/ChamferDistanceTransform.h \
    include/CloudSamplingTools.h \
    include/ConjugateGradient.h \
    include/Delaunay2dMesh.h \
    include/DgmOctree.h \
    include/DgmOctreeReferenceCloud.h \
    include/DistanceComputationTools.h \
    include/ErrorFunction.h \
    include/FastMarching.h \
    include/FastMarchingForPropagation.h \
    include/Garbage.h \
    include/GenericCloud.h \
    include/GenericDistribution.h \
    include/GenericIndexedCloud.h \
    include/GenericIndexedCloudPersist.h \
    include/GenericIndexedMesh.h \
    include/GenericMesh.h \
    include/GenericOctree.h \
    include/GenericProgressCallback.h \
    include/GenericTriangle.h \
    include/GeometricalAnalysisTools.h \
    include/Grid3D.h \
    include/Jacobi.h \
    include/KdTree.h \
    include/LocalModel.h \
    include/ManualSegmentationTools.h \
    include/MathTools.h \
    include/MeshSamplingTools.h \
    include/Neighbourhood.h \
    include/NormalDistribution.h \
    include/ParallelSort.h \
    include/PointCloud.h \
    include/PointCloudTpl.h \
    include/PointProjectionTools.h \
    include/Polyline.h \
    include/RayAndBox.h \
    include/ReferenceCloud.h \
    include/RegistrationTools.h \
    include/SaitoSquaredDistanceTransform.h \
    include/ScalarField.h \
    include/ScalarFieldTools.h \
    include/SimpleMesh.h \
    include/SimpleTriangle.h \
    include/SquareMatrix.h \
    include/StatisticalTestingTools.h \
    include/TrueKdTree.h \
    include/WeibullDistribution.h \
    src/Chi2Helper.h

SOURCES += \
    src/AutoSegmentationTools.cpp \
    src/BoundingBox.cpp \
    src/CCMiscTools.cpp \
    src/CCShareable.cpp \
    src/ChamferDistanceTransform.cpp \
    src/CloudSamplingTools.cpp \
    src/Delaunay2dMesh.cpp \
    src/DgmOctree.cpp \
    src/DgmOctreeReferenceCloud.cpp \
    src/DistanceComputationTools.cpp \
    src/ErrorFunction.cpp \
    src/FastMarching.cpp \
    src/FastMarchingForPropagation.cpp \
    src/GeometricalAnalysisTools.cpp \
    src/KdTree.cpp \
    src/LocalModel.cpp \
    src/ManualSegmentationTools.cpp \
    src/MeshSamplingTools.cpp \
    src/Neighbourhood.cpp \
    src/NormalDistribution.cpp \
    src/NormalizedProgress.cpp \
    src/PointProjectionTools.cpp \
    src/Polyline.cpp \
    src/ReferenceCloud.cpp \
    src/RegistrationTools.cpp \
    src/SaitoSquaredDistanceTransform.cpp \
    src/ScalarField.cpp \
    src/ScalarFieldTools.cpp \
    src/SimpleMesh.cpp \
    src/StatisticalTestingTools.cpp \
    src/TrueKdTree.cpp \
    src/WeibullDistribution.cpp

    然后将CloudCompare源码中对应的源文件，拷贝到自己对应的工程目录下。

    最后构建完后的工程如下图所示：

3 修改源码

    由于CloudCompare源码是基于Qt5的，换成Qt6后要修改部分源码。下面是我记录的要修改的内容：

//修改内容1:
inline ccQOpenGLFunctions* functions() const { return context() ? context()->versionFunctions<ccQOpenGLFunctions>() : nullptr; }//源码
inline ccQOpenGLFunctions* functions() const { return context() ? (ccQOpenGLFunctions*)context()->functions () : nullptr; }//修改后

//修改内容2:
<<endl;//源码
<<Qt::endl;//修改后
//修改内容3:
      stream.readNextStartElement();
            QString itemName = stream.name().toString();
      QString itemValue = stream.readElementText();
            ccLog::Print(QString("[XML] Item '%1': '%2'").arg(itemName,itemValue));
//            QStringRef itemName = stream.name();
//      QString itemValue = stream.readElementText();
//      ccLog::Print(QString("[XML] Item '%1': '%2'").arg(itemName.toString(),itemValue));
//修改内容4:
    QOpenGLFunctions_2_1* glFunc = (QOpenGLFunctions_2_1*)context->functions();//修改后
//    QOpenGLFunctions_2_1* glFunc = context->versionFunctions<QOpenGLFunctions_2_1>();

//修改内容5:
//    QStringList tokens = currentLine.simplified().split(QChar(' '), QString::SkipEmptyParts);
        QStringList tokens = currentLine.simplified().split(QChar(' '), Qt::SkipEmptyParts);
//修改内容6:
//#include <QGLBuffer>
#include <QOpenGLBuffer>

//修改内容7:
//            xShift = tab.colWidth[c] - QFontMetrics(bodyFont).width(str);
                        xShift = tab.colWidth[c] - QFontMetrics(bodyFont).horizontalAdvance(str);

//修改内容8:
//        float sizeModifier = (event->delta() < 0 ? -1.0f : 1.0f);
        float sizeModifier = (event->angleDelta().y() < 0 ? -1.0f : 1.0f);

//修改内容9:
//  return QStringLiteral( "Created %1" ).arg( QDateTime::currentDateTime().toString( Qt::SystemLocaleShortDate ) );
    return QStringLiteral( "Created %1" ).arg( QDateTime::currentDateTime().toString("yyyy/MM/dd hh:mm") );

//修改内容10:
//  QSize screenSize = QApplication::desktop()->screenGeometry().size();
    QSize screenSize = QGuiApplication::primaryScreen()->availableSize();
//修改内容11:
//    if (sep == 4) //comma 
    if (sep == QChar(44)) //comma

//                if (lsfDlg.listWidget->isItemSelected(lsfDlg.listWidget->item(i)))
                                if (lsfDlg.listWidget->item(i)->isSelected())
//修改内容12:
//  foreach (QCPItemPosition *child, mChildrenX.toList()) 
    foreach (QCPItemPosition *child, mChildrenX.values())

//修改内容13:
//    painter.setRenderHint(QPainter::HighQualityAntialiasing);
      painter.setRenderHint(QPainter::Antialiasing); // to make Antialiasing look good if using the OpenGL graphicssystem
    
//修改内容14:
//  if (QCPLayoutElement *el = layoutElementAt(event->pos()))
    if (QCPLayoutElement *el = layoutElementAt(event->position()))
    
//修改内容15:
//        mColorBuffer[i] = (it-1).value().rgb();
          --it;
        mColorBuffer[i] = it.value().rgb();



//修改内容16:
//    mAxisRect.data()->setRangeDrag(0);
    mAxisRect.data()->setRangeDrag(QCPAxis::orientation(QCPAxis::AxisType(0)));
  
  
  
//修改内容17:
//      QCPDataMap::const_iterator upperEnd = upper+1;
      QCPDataMap::const_iterator upperEnd = ++upper;--upper;
  
//修改内容18:
//    newData.t = (mData->constEnd()-1).key()+1;
  QCPCurveDataMap::const_iterator upperEnd = mData->constEnd();--upperEnd;
  if (!mData->isEmpty())
    newData.t = upperEnd.key()+1;
  
//修改内容19:
    if (command == PDMS_LAST)
  {
    if (s_elementsStack.size() < 2)
            return false;
//        ElementsStack::iterator it = s_elementsStack.end(); --it;
        ElementsStack::iterator i = s_elementsStack.begin();
        ElementsStack::iterator j = s_elementsStack.begin();
        for (; i != s_elementsStack.end(); j=i,++i) {}
        ElementsStack::iterator it = j;
    if (isSet() == 1)
    {
//      while (true)
//      {
//        if (isNameReference() && strcmp(refname, (*it)->name) == 0)
//          break;
//        if (isTokenReference() && (*it)->getType() == token)
//          break;
//        if (it == s_elementsStack.begin())
//          return false;
//        --it;
//      }
            for (ElementsStack::iterator tmp = s_elementsStack.begin(); tmp != j; ++tmp) {
                it = tmp;
                if (isNameReference() && strcmp(refname, (*it)->name) == 0)
                    break;
                if (isTokenReference() && (*it)->getType() == token)
                    break;
                if (it == s_elementsStack.begin())
                    return false;
            }
    }
    item = *it;
    return true;
  }
  
//修改内容20:
//  ccViewer(QWidget *parent = 0, Qt::WindowFlags flags = 0);
    ccViewer(QWidget *parent = 0, Qt::WindowFlags flags = Qt::Widget);

4 编译源码

    编译成功后，拷贝对应的库到程序目录，运行程序后效果如下：

  我以将测试源码放到CSDN上面，有需要可以下载。

https://download.csdn.net/download/qq_40732350/85230547