PCL 矩阵变换

// 创建仿射变换对象
Eigen::Affine3f transform_2 = Eigen::Affine3f::Identity();
// 在x轴平移0.8m
transform_2.translation() << 0.8, 0.0, 0.0;
// 绕Z轴先转45度（逆时针）
transform_2.rotate(Eigen::AngleAxisf(M_PI / 4;, Eigen::Vector3f::UnitZ()));
// 打印仿射变换矩阵
printf("\nMethod #2: using an Affine3f\n");
std::cout << transform_2.matrix() << std::endl;
// 创建变换后的点云
pcl::PointCloud<pcl::PointXYZ>::Ptr transformed_cloud(new pcl::PointCloud<pcl::PointXYZ>());

// 执行变换， source_cloud为变换前的点云
pcl::transformPointCloud(*source_cloud, *transformed_cloud, transform_2);

#include <iostream>

#include <pcl/io/pcd_io.h>
#include <pcl/io/ply_io.h>
#include <pcl/point_cloud.h>
#include <pcl/console/parse.h>
#include <pcl/common/transforms.h>
#include <pcl/visualization/pcl_visualizer.h>

/**
 * 旋转并平移
 * @param argc
 * @param argv
 * @return
 */
int
main(int argc, char **argv) {


    // Load file | Works with PCD and PLY files
    pcl::PointCloud<pcl::PointXYZ>::Ptr source_cloud(new pcl::PointCloud<pcl::PointXYZ>());
    pcl::io::loadPLYFile("C:\\0APractice\\PclLearning\\PCLTransform\\Desk1.ply", *source_cloud);

	/*if (pcl::io::loadPCDFile(argv[1], *source_cloud) < 0) {
		std::cout << "Error loading point cloud" << argv[1] << std::endl << std::endl;
		return -1;
	}*/
    
    /* Reminder: how transformation matrices work :

             |-------> This column is the translation
      | 1 0 0 x |  \
      | 0 1 0 y |   }-> The identity 3x3 matrix (no rotation) on the left
      | 0 0 1 z |  /
      | 0 0 0 1 |    -> We do not use this line (and it has to stay 0,0,0,1)

      METHOD #1: Using a Matrix4f
      This is the "manual" method, perfect to understand but error prone !
    */
    Eigen::Matrix4f transform_1 = Eigen::Matrix4f::Identity();

    // Define a rotation matrix (see https://en.wikipedia.org/wiki/Rotation_matrix)
    float theta = M_PI / 4; // The angle of rotation in radians
    transform_1(0, 0) = cos(theta);
    transform_1(0, 1) = -sin(theta);
    transform_1(1, 0) = sin(theta);
    transform_1(1, 1) = cos(theta);
    //    (row, column)

    // Define a translation of 2.5 meters on the x axis.
    transform_1(0, 3) = 2.5;

    // Print the transformation
    printf("Method #1: using a Matrix4f\n");
    std::cout << transform_1 << std::endl;

    /*  METHOD #2: Using a Affine3f
      This method is easier and less error prone
    */
    Eigen::Affine3f transform_2 = Eigen::Affine3f::Identity();

    // Define a translation of 0.8 meters on the x axis.
    transform_2.translation() << 0.8, 0.0, 0.0;

    // The same rotation matrix as before; theta radians arround Z axis
    transform_2.rotate(Eigen::AngleAxisf(theta, Eigen::Vector3f::UnitZ()));

    // Print the transformation
    printf("\nMethod #2: using an Affine3f\n");
    std::cout << transform_2.matrix() << std::endl;

    // Executing the transformation
    pcl::PointCloud<pcl::PointXYZ>::Ptr transformed_cloud(new pcl::PointCloud<pcl::PointXYZ>());
    // You can either apply transform_1 or transform_2; they are the same
    pcl::transformPointCloud(*source_cloud, *transformed_cloud, transform_2);

    // Visualization
    printf("\nPoint cloud colors :  white  = original point cloud\n"
           "                        red  = transformed point cloud\n");
    pcl::visualization::PCLVisualizer viewer("Matrix transformation example");

    // Define R,G,B colors for the point cloud
    pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> source_cloud_color_handler(source_cloud, 255, 255, 255);
    // We add the point cloud to the viewer and pass the color handler
    viewer.addPointCloud(source_cloud, source_cloud_color_handler, "original_cloud");

    pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> transformed_cloud_color_handler(transformed_cloud, 230, 20, 20); // Red
    viewer.addPointCloud(transformed_cloud, transformed_cloud_color_handler, "transformed_cloud");

    // 设置坐标系系统
    viewer.addCoordinateSystem(0.5, "cloud", 0);
    // 设置背景色
    viewer.setBackgroundColor(0.05, 0.05, 0.05, 0); // Setting background to a dark grey
    // 设置渲染属性（点大小）
    viewer.setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 2, "original_cloud");
    // 设置渲染属性（点大小）
    viewer.setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 2, "transformed_cloud");
    //viewer.setPosition(800, 400); // Setting visualiser window position

    while (!viewer.wasStopped()) { // Display the visualiser until 'q' key is pressed
        viewer.spinOnce();
    }

    return 0;
}