如何在PCL Viewer中同时绘制点云曲线与样条曲线？

Hey there! Since PCL's Visualizer is built on top of VTK, you don't need separate windows for your point cloud and spline. You can directly inject your VTK-generated spline actor into the PCL Viewer's rendering pipeline. Here's a modified version of your code that combines both visualizations:

#include <pcl/io/pcd_io.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <vtkPoints.h>
#include <vtkParametricSpline.h>
#include <vtkParametricFunctionSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkInteractorStyleSwitch.h>

int main() {
    // Load the point cloud
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_curve(new pcl::PointCloud<pcl::PointXYZ>);
    if (pcl::io::loadPCDFile<pcl::PointXYZ>("line.pcd", *cloud_curve) == -1) {
        PCL_ERROR("Couldn't read the pcd file.\n");
        exit(1);
    }

    // Initialize PCL Viewer
    boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer("Point Cloud + Spline Viewer"));
    viewer->setBackgroundColor(0, 0, 0);
    
    // Add point cloud to viewer
    pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> handler(cloud_curve, 255, 0, 0);
    viewer->addPointCloud(cloud_curve, handler, "cloud");

    // --------------------------
    // VTK Spline Creation Logic
    // --------------------------
    double p0[3] = {-5.91152, 4.65316, 28063.7};
    double p1[3] = {-6.2126, 3.8805, 28034.9};
    double p2[3] = {-6.54915, 4.6517, 28007};

    vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
    points->InsertNextPoint(p0);
    points->InsertNextPoint(p1);
    points->InsertNextPoint(p2);

    vtkSmartPointer<vtkParametricSpline> spline = vtkSmartPointer<vtkParametricSpline>::New();
    spline->SetPoints(points);

    vtkSmartPointer<vtkParametricFunctionSource> functionSource = vtkSmartPointer<vtkParametricFunctionSource>::New();
    functionSource->SetParametricFunction(spline);
    functionSource->Update();

    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(functionSource->GetOutputPort());

    vtkSmartPointer<vtkActor> splineActor = vtkSmartPointer<vtkActor>::New();
    splineActor->SetMapper(mapper);
    splineActor->GetProperty()->SetColor(0, 255, 0); // Green spline to contrast red point cloud
    splineActor->GetProperty()->SetLineWidth(2); // Thicker line for better visibility

    // --------------------------
    // Add VTK Actor to PCL Viewer
    // --------------------------
    // Access PCL Viewer's underlying VTK renderer
    vtkRenderer* renderer = viewer->getRendererCollection()->GetFirstRenderer();
    renderer->AddActor(splineActor);

    // Set up camera and interactor style
    viewer->initCameraParameters();
    
    // Optional: Match VTK's trackball camera navigation style
    vtkInteractorStyleSwitch* style = vtkInteractorStyleSwitch::New();
    style->SetCurrentStyleToTrackballCamera();
    viewer->getRenderWindow()->GetInteractor()->SetInteractorStyle(style);
    style->Delete(); // Clean up unmanaged VTK object

    // Start rendering loop
    while (!viewer->wasStopped()) {
        viewer->spinOnce(100);
        boost::this_thread::sleep(boost::posix_time::microseconds(100000));
    }

    return 0;
}

Key Details to Note: #

• PCL-VTK Interoperability: PCL Visualizer relies on VTK internally, so we can grab its vtkRenderer and add any VTK actor directly to it—no need to maintain separate windows.
• Visibility Tweaks: I adjusted the spline color and line width to make it easy to distinguish from the point cloud; feel free to tweak these values to your preference.
• Interactor Consistency: The optional trackball camera style ensures navigation behaves the same way as your standalone VTK window, making the experience more familiar.
• Memory Management: Be sure to clean up VTK objects that aren't handled by smart pointers (like the interactor style here) to avoid memory leaks.

内容的提问来源于stack exchange，提问作者GStav