pcl按照z方向渲染点云，但是CMakelists.txt编译找不到pcl/io/pcd_io.h: 没有那个文件或目录，Eigen找不到

每次都找不到最简单的显示代码，刚好又报错了，索性记录一下：

/usr/include/pcl/point_cloud.h:46:10: fatal error: Eigen/StdVector: 没有那个文件或目录
 #include <Eigen/StdVector>

找不到pcl/io/pcd_io.h: 没有那个文件或目录

这是因为include的时候，找都是在/usr/include/这个路径，而其带了一些前缀，所以这样操作就好了

sudo ln -s /usr/include/eigen3/Eigen/ /usr/include/Eigen

sudo ln -s /usr/include/pcl-1.8/Eigen/ /usr/include/pcl

还有一点就算pcl只能读取float类型的pcd和ply文件。。。。，然后open3d好像默认生成的是double的类型，所以自己用文本编辑器改一下类型可以，改称这样就ok了：

ply
format ascii 1.0
comment Created by Open3D
element vertex 2668816
property float x
property float y
property float z
property uchar red
property uchar green
property uchar blue
end_header

代码如下

#include <iostream>
#include <pcl/io/pcd_io.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <pcl/io/ply_io.h>//PCL的PLY格式文件的输入输出头文件


using namespace std;

typedef pcl::PointXYZ PointT;

int main(int argc, char* argv[])
{
	if(argc < 2) return 0;
	string pcd_path = argv[1];
	//------------------------------------ 加载点云 ---------------------------------
	pcl::PointCloud<PointT>::Ptr cloud(new pcl::PointCloud<PointT>);
	pcl::PCDReader reader;	
	if (pcl::io::loadPLYFile <pcl::PointXYZ>(pcd_path, *cloud) == -1)//读取PLY文件
	//if (pcl::io::loadPCDFile <pcl::PointXYZ>(pcd_path, *cloud) == -1)
	{
		PCL_ERROR("\a->点云文件不存在！\n");
		system("pause");
		return -1;
	}
	cout << "->加载了 " << cloud->points.size() << " 个数据点" << endl;
	//==============================================================================

	//------------------------------- 自定义颜色显示 --------------------------------
	boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer("指定坐标字段渲染"));
	pcl::visualization::PointCloudColorHandlerGenericField<PointT> renderColor(cloud, "z");						//指定坐标字段
	viewer->addPointCloud<PointT>(cloud, renderColor, "sample_cloud");											//添加点云和颜色信息
	viewer->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 3, "sample_cloud");	//设置点的大小

	while (!viewer->wasStopped())
	{
		viewer->spinOnce(100);
		boost::this_thread::sleep(boost::posix_time::microseconds(10000));
	}
	//==============================================================================

	return 0;
}

CMakeLists.txt如下：

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)

project(project_name)
set( CMAKE_BUILD_TYPE "Debug" )
set(CMAKE_CXX_FLAGS   "-std=c++11")

find_package(PCL 1.8 REQUIRED)

message("PCL_INCLUDE_DIRS=${PCL_INCLUDE_DIRS}")

add_executable (show_pcd show_pcd.cpp) 

target_link_libraries(show_pcd ${PCL_LIBRARIES})

reference：
https://blog.csdn.net/weixin_46098577/article/details/115530811?spm=1001.2014.3001.5501
https://blog.csdn.net/qq_43393323/article/details/107128451