ROSIntegration ROSIntegrationVision与虚幻引擎4（Unreal Engine 4）的配置
ROSIntegration ROSIntegrationVision与虚幻引擎4（Unreal Engine 4）的配置
操作系统：Ubuntu 18.04
虚幻引擎：4.26.2
目录- 虚幻引擎Linux快速入门
二、ROSIntegration下载与配置运行
1、配置ROSBridge
要启用虚幻和ROS之间的通信，需要一个正在运行的ROSBridge和bson_mode
注意：请使用 rosbridge 版本=>0.8.0 以获得完整的 BSON 支持
安装rosbridge的推荐方法是在ROS工作空间使用源代码进行编译，即把rosbridge作为其中一个功能包，按照如下命令顺序执行
sudo apt-get install ros-ROS1_DISTRO-rosauth # 将 ROS1_DISTRO 替换为ROS对应的版本名称cd ~/ros_workspace/ # 替换 ros_workspace 为工作空间目录名称 source devel/setup.bash cd src/ git clone -b ros1 https://github.com/RobotWebTools/rosbridge_suite.git cd .. catkin_make source devel/setup.bash此外，ROSIntegration使用包含在PyMongo包中的BSON，可以单独安装
sudo pip3 install pymongo2、配置ROSIntegration
使用git命令下载ROSIntegration，放置在虚幻引擎项目文件Plugins文件夹下
cd unreal_engine_project # 替换 unreal_engine_project 为项目目录文件夹路径 mkdir Plugins # 如果没有 Plugins 文件夹则手动创建 cd Plugins git clone https://github.com/code-iai/ROSIntegration.git此时，ROSIntegration在虚幻项目中的文件结构如下：
unreal_engine_project/Plugins/ROSIntegration/ROSIntegration.uplugin
在虚幻引擎源代码UnrealEngine下的Engine/Source/Developer/DesktopPlatform/Private/DesktopPlatformBase.cpp文件中执行此操作
查找此行：
Arguments += " -Progress -NoEngineChanges -NoHotReloadFromIDE";替换为：
Arguments += " -Progress";然后重新编译引擎：
cd UnrealEngine ./Setup.sh ./GenerateProjectFiles.sh make编译完成后，启动项目并接受重建
（如果不进行上述步骤可能会遇到虚幻引擎自建项目打不开或遇到engine modules are out of date and cannot be compiled while the engine is running的情况）
创建一个新的C++虚幻项目，或打开现有项目
在内容浏览器中查找（在内容浏览器的右下角启用“查看选项”>“显示插件内容”）
点击“添加/导入”按钮下方的三条线按钮，展开左侧区域
选中“ROSIntegration“>“Classes”，右键ROSIntegrationGameInstance，点击下图黄色选项
打开新的C++类/蓝图对象，并更改
ROSBridgeSeverHost和ROSBridgeServerPort，如果是本地运行的ROSBridge，则改为127.0.0.1即可打开“地图和模式”>“项目设置”，并将游戏实例设置为与新的游戏实例对象匹配，比如
MyROSIntegrationGameInstance，而不是插件中的ROSIntegrationGameInstance
使用Ctrl + Shift + S保存所有更改
3、使用ROSIntegration
要进行与 ROS 的简单发布/订阅通信，需要在创建一个新的C++ Actor，而非中文的角色（Charactor）。
接着创建 SamplePubliserSamplePublisher.h
#include "ROSIntegration/Classes/RI/Topic.h" #include "ROSIntegration/Classes/ROSIntegrationGameInstance.h" #include "ROSIntegration/Public/std_msgs/String.h"注意：上述代码必须在
#include "SamplePublisher.generated.h"之前，否则会报错SamplePublisher.cpp
// Initialize a topic UTopic *ExampleTopic = NewObject(UTopic::StaticClass()); UROSIntegrationGameInstance* rosinst = Cast (GetGameInstance()); ExampleTopic->Init(rosinst->ROSIntegrationCore, TEXT("/example_topic"), TEXT("std_msgs/String")); // (Optional) Advertise the topic ExampleTopic->Advertise(); // Publish a string to the topic TSharedPtr 注意：上述代码放置在
BeginPlay()函数中进入unreal_engine_project/Source/unreal_engine_project目录（替换 unreal_engine_project 为真实的项目名称），打开unreal_engine_project.Build.cs文件
找到:
PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore" });添加ROSIntegrationy依赖，形如：
PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "ROSIntegration" });进入ROS工作空间的src目录，创建测试功能包：
catkin_create_pkg ue_test std_msgs rospy roscpp编译并source：
catkin_make source devel/setup.bash创建一个监听者cpp文件：
cd ue_test/src touch listener.cpp打开cpp并键入如下代码：
#include "ros/ros.h" #include "std_msgs/String.h" /** * This tutorial demonstrates simple receipt of messages over the ROS system. */ void chatterCallback(const std_msgs::String::ConstPtr& msg) { ROS_INFO("I heard: [%s]", msg->data.c_str()); } int main(int argc, char **argv) { /** * The ros::init() function needs to see argc and argv so that it can perform * any ROS arguments and name remapping that were provided at the command line. * For programmatic remappings you can use a different version of init() which takes * remappings directly, but for most command-line programs, passing argc and argv is * the easiest way to do it. The third argument to init() is the name of the node. * * You must call one of the versions of ros::init() before using any other * part of the ROS system. */ ros::init(argc, argv, "listener"); /** * NodeHandle is the main access point to communications with the ROS system. * The first NodeHandle constructed will fully initialize this node, and the last * NodeHandle destructed will close down the node. */ ros::NodeHandle n; /** * The subscribe() call is how you tell ROS that you want to receive messages * on a given topic. This invokes a call to the ROS * master node, which keeps a registry of who is publishing and who * is subscribing. Messages are passed to a callback function, here * called chatterCallback. subscribe() returns a Subscriber object that you * must hold on to until you want to unsubscribe. When all copies of the Subscriber * object go out of scope, this callback will automatically be unsubscribed from * this topic. * * The second parameter to the subscribe() function is the size of the message * queue. If messages are arriving faster than they are being processed, this * is the number of messages that will be buffered up before beginning to throw * away the oldest ones. */ ros::Subscriber sub = n.subscribe("/example_topic", 1000, chatterCallback); /** * ros::spin() will enter a loop, pumping callbacks. With this version, all * callbacks will be called from within this thread (the main one). ros::spin() * will exit when Ctrl-C is pressed, or the node is shutdown by the master. */ ros::spin(); return 0; }在CMakeLists.txt添加：
add_executable(listener src/listener.cpp) target_link_libraries(listener ${catkin_LIBRARIES}) add_dependencies(listener listener)4、测试ROSIntegration
启动rosbridge
roslaunch rosbridge_server rosbridge_tcp.launch bson_only_mode:=True运行新建功能包的监听者
# rosruntalker # 比如 rosrun ue_test talker 将在UE中新建的SamplePublisher托入三维世界中，并点击运行
此时可以看到：
[INFO] [1588662504.536355639]: I heard: [This is an example]恭喜你成功配置并运行了ROSIntegration！！！
三、ROSIntegrationVision下载与配置运行
1、虚幻引擎配置修改
在PATH_TO_UNREAL/Engine/Source/Programs/UnrealBuildTool/Platform/Linux/LinuxToolChain.cs中找到
GetCLArguments_Global函数，并在其中添加语句Result += " -mf16c";，形如：protected virtual string GetCLArguments_Global(CppCompileEnvironment CompileEnvironment) { string Result = ""; // build up the commandline common to C and C++ Result += " -c"; Result += " -pipe"; Result += " -mf16c"; if (ShouldUseLibcxx(CompileEnvironment.Architecture)) { Result += " -nostdinc++"; Result += " -I" + "ThirdParty/Linux/LibCxx/include/"; Result += " -I" + "ThirdParty/Linux/LibCxx/include/c++/v1"; }而后重新编译虚幻引擎（注意如下语句必须都执行才算是重新编译）：
cd UnrealEngine ./Setup.sh ./GenerateProjectFiles.sh make2、配置ROSIntegrationVision
使用git命令下载ROSIntegrationVision，放置在虚幻引擎项目文件Plugins文件夹下
cd unreal_engine_project # 替换 unreal_engine_project 为项目目录文件夹路径 mkdir Plugins # 如果没有 Plugins 文件夹则手动创建 cd Plugins git clone https://github.com/code-iai/ROSIntegrationVision/.git如果你是在Linux上编译虚幻引擎4而非Windows，则在打开项目时可能会遇到
Building forest2Editor... Performing 3 actions (6 in parallel) [1/3] Compile Module.ROSIntegrationVision.cpp In file included from .../Plugins/ROSIntegrationVision/Intermediate/Build/Linux/B4D820EA/UE4Editor/Development/ROSIntegrationVision/Module.ROSIntegrationVision.cpp:6: .../Plugins/ROSIntegrationVision/Source/ROSIntegrationVision/Private/VisionComponent.cpp:754:4: error: use of undeclared identifier '_mm_div_epi16'; did you mean '_mm_min_epi16'? _mm_div_epi16( ^~~~~~~~~~~~~ _mm_min_epi16 /home/pisces/Gitware/UnrealEngine/Engine/Extras/ThirdPartyNotUE/SDKs/HostLinux/Linux_x64/v17_clang-10.0.1-centos7/x86_64-unknown-linux-gnu/lib/clang/10.0.1/include/emmintrin.h:2412:1: note: '_mm_min_epi16' declared here _mm_min_epi16(__m128i __a, __m128i __b) ^ 1 error generated. LogInit: Warning: Still incompatible or missing module: ROSIntegrationVision这是由于官方参考了Windows for UVisionComponent上的编译问题：：convertDepth #28这一问题的回答，将源码改为了适配Windows的环境，但在Ubuntu18.04中并不存在
_mm_div_epi16这一函数因而，改变代码
void UVisionComponent::convertDepth(const uint16_t *in, __m128 *out) const { const size_t size = (Width * Height) / 4; for (size_t i = 0; i < size; ++i, in += 4, ++out) { // Divide by 100 here in order to convert UU (cm) into ROS units (m) *out = _mm_cvtph_ps( _mm_div_epi16( _mm_set_epi16(0, 0, 0, 0, *(in + 3), *(in + 2), *(in + 1), *(in + 0)), _mm_set_epi16(100, 100, 100, 100, 100, 100, 100, 100) ) );// / 100; } }void UVisionComponent::convertDepth(const uint16_t *in, __m128 *out) const { const size_t size = (Width * Height) / 4; for (size_t i = 0; i < size; ++i, in += 4, ++out) { // Divide by 100 here in order to convert UU (cm) into ROS units (m) *out = _mm_cvtph_ps(_mm_set_epi16( 0, 0, 0, 0, *(in + 3), *(in + 2), *(in + 1), *(in + 0))) / 100; } }即可成功自动编译打开项目
3、使用ROSIntegrationVision
在内容浏览器ROSIntegrationVision/ROSIntegrationVision/Private中包含VisionActor C++文件，将其托入三维世界中即可现实摄像头图像信息
4、问题
注意：使用时需要先在VisionActor.cpp中作如下修改
AVisionActor::AVisionActor() : AActor() { UE_LOG(LogTemp, Warning, TEXT("VisionActor CTOR")); // Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it. PrimaryActorTick.bCanEverTick = true; RootComponent = CreateDefaultSubobject(TEXT("Root")); SetRootComponent(RootComponent); vision = CreateDefaultSubobject (TEXT("Vision")); vision->DisableTFPublishing = true; // 添加 //vision->ParentLink = "/world"; 注释掉 vision->ParentLink = "desired_link"; // 添加 vision->SetupAttachment(RootComponent); } 将ROSIntegrationVision插件中的Binaries和Intermediate文件夹删除，重新打开项目，使引擎重新编译插件
如果在运行rosbridge时遇到如下问题
可以修改ROSIntegration/Source/ROSIntegration/Private/Conversion/Messages/sensor_msgs/SensorMsgsCameraInfoConverter.h文件
替换
static void _bson_append_camera_info(bson_t *b, const ROSMessages::sensor_msgs::CameraInfo *msg) { // assert(CastMsg->D.Num() == 5); // TODO: use Unreal assertions assert(CastMsg->K.Num() == 9); // TODO: use Unreal assertions assert(CastMsg->R.Num() == 9); assert(CastMsg->P.Num() == 12); UStdMsgsHeaderConverter::_bson_append_child_header(b, "header", &msg->header); BSON_APPEND_INT32(b, "height", msg->height); BSON_APPEND_INT32(b, "width", msg->width); BSON_APPEND_UTF8(b, "distortion_model", TCHAR_TO_UTF8(*msg->distortion_model)); _bson_append_double_tarray(b, "d", msg->D); _bson_append_double_tarray(b, "k", msg->K); _bson_append_double_tarray(b, "r", msg->R); _bson_append_double_tarray(b, "p", msg->P); BSON_APPEND_INT32(b, "binning_x", msg->binning_x); BSON_APPEND_INT32(b, "binning_y", msg->binning_y); USensorMsgsRegionOfInterestConverter::_bson_append_child_roi(b, "roi", &msg->roi); }static void _bson_append_camera_info(bson_t *b, const ROSMessages::sensor_msgs::CameraInfo *msg) { // assert(CastMsg->D.Num() == 5); // TODO: use Unreal assertions assert(CastMsg->K.Num() == 9); // TODO: use Unreal assertions assert(CastMsg->R.Num() == 9); assert(CastMsg->P.Num() == 12); UStdMsgsHeaderConverter::_bson_append_child_header(b, "header", &msg->header); BSON_APPEND_INT32(b, "height", msg->height); BSON_APPEND_INT32(b, "width", msg->width); BSON_APPEND_UTF8(b, "distortion_model", TCHAR_TO_UTF8(*msg->distortion_model)); _bson_append_double_tarray(b, "D", msg->D); // 替换 _bson_append_double_tarray(b, "K", msg->K); // 替换 _bson_append_double_tarray(b, "R", msg->R); // 替换 _bson_append_double_tarray(b, "P", msg->P); // 替换 BSON_APPEND_INT32(b, "binning_x", msg->binning_x); BSON_APPEND_INT32(b, "binning_y", msg->binning_y); USensorMsgsRegionOfInterestConverter::_bson_append_child_roi(b, "roi", &msg->roi); }如果相机图象FPS较低，可以考虑修改VisionComponent.cpp中
Framerate(1)为Framerate(100)UVisionComponent::UVisionComponent() : Width(640), Height(480), Framerate(100), // change 1 to 100 UseEngineFramerate(false), ServerPort(10000), FrameTime(1.0f / Framerate), TimePassed(0), ColorsUsed(0)四、参考资料
[1] code-iai/ROSIntegration markdown说明文档及issues
[2] code-iai/ROSIntegrationVision markdown说明文档及issues
[3] ROS Communication Sample on Unreal Engine Using ROSIntegration
[4] upgrade c++ project from ue 4.24 to 4.25 under Linux
部分图片来源于网络
转载请注明出处！
本篇发布在以下博客或网站：
双鱼座羊驼 - 知乎 (zhihu.com)
双鱼座羊驼的博客_CSDN博客
双鱼座羊驼 - SegmentFault 思否
双鱼座羊驼 的个人主页 - 动态 - 掘金 (juejin.cn)
双鱼座羊驼 - 博客园 (cnblogs.com)