docker搭建ros-indigo-arm交叉编译环境

ROS运行环境：ARM ubuntu14.04 + ROS indigo
在arm环境下编译ros应用程序，速度极慢，无法忍受，尝试在x86机器上搭建docker+ros交叉编译环境。

交叉编译环境的搭建主要参考：

http://answers.ros.org/question/191070/compile-roscore-for-arm-board/

1 ARM ubuntu环境上安装arm-indigo版本,后面需要将这个arm版本copy到交叉编译环境上
2 x86环境上安装docker
3 下载docker-ros镜像， 加载启动docker-ros镜像
4 安装 sudo apt-get install g++-arm-linux-gnueabihf
5 将docker环境中中x86版本的indigo替换成arm版本的indigo,
替换之前需要备份x86版本indigo的lib,因为这些库文件在运行ros时是需要的。
将x86版本indigo的lib保存到localpath目录下，设置export LD_LIBRARY_PATH=localpath，
实现运行ros命令时使用x86的lib库。
6 将arm环境下的库文件/头文件 copy到docker环境中，目录可以自己设定比如：/$ENV{HOME}/cross-compiling/ubuntu-rootfs
7 配置rostoolchain.cmake文件

#File rostoolchain.cmake

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_C_COMPILER /usr/bin/arm-linux-gnueabihf-gcc)
set(CMAKE_CXX_COMPILER /usr/bin/arm-linux-gnueabihf-g++)
set(CMAKE_FIND_ROOT_PATH /opt/ros/indigo $ENV{HOME}/cross-compiling/ubuntu-rootfs)

set(CMAKE_LIBRARY_PATH $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/lib/arm-linux-gnueabihf $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/lib $ENV{HOME}/cross-compiling/ubuntu-rootfs/lib $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/local/lib)

set(CMAKE_INCLUDE_PATH $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/include $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/local/include)
set(LD_LIBRARY_PATH $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/lib/arm-linux-gnueabihf $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/lib $ENV{HOME}/cross-compiling/ubuntu-rootfs/lib $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/local/lib)

set(PYTHON_EXECUTABLE /usr/bin/python)
set(PCL_ROOT $ENV{HOME}/cross-compiling/ubuntu-rootfs/usr)

set(CMAKE_CROSSCOMPILING true)
message("${CMAKE_CROSSCOMPILING}")

# Have to set this one to BOTH, to allow CMake to find rospack

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

8 修改/opt/ros/indigo/share/catkin/cmake/tools/rt.cmake

该文件的第34行

if(NOT (APPLE OR WIN32 OR MINGW OR ANDROID))修改为if(NOT (APPLE OR WIN32 OR MINGW OR ANDROID OR UNIX))

9 个人理解cmake交叉编译过程就是修改cmake搜索链接库文件位置的过程，正常编译会搜索x86库文件做在位置，
交叉编译需要将搜索位置切换到目标架构需要的库文件存放位置，比如/$ENV{HOME}/cross-compiling/ubuntu-rootfs
实现方法：
修改catkin_INCLUDE_DIRS catkin_LIBRARY_DIRS，将这两个变量中指向x86系统的位置，修改为指向交叉编译依赖文件存放位置
/opt/ros/indigo/share/catkin/cmake/catkinConfig.cmake
这个文件末增加如下处理:

list(APPEND catkin_INCLUDE_DIRS ${CMAKE_INCLUDE_PATH})
list(APPEND catkin_LIBRARY_DIRS ${CMAKE_LIBRARY_PATH})

set(catkin_LIBRARIES_tmp ${catkin_LIBRARIES})
set(catkin_LIBRARIES "")
foreach(catkinlib ${catkin_LIBRARIES_tmp})
    string(LENGTH ${catkinlib} lengths)
    if (${lengths} GREATER 12)
        string(SUBSTRING ${catkinlib} "/" 12 result)
        string(COMPARE EQUAL ${result} "/usr/lib/lib" compareResult)
        if (${compareResult})
            string(REPLACE "/usr/lib/lib" "$ENV{HOME}/cross-compiling/ubuntu-rootfs/usr/lib/lib" result_tem ${catkinlib})
            list(APPEND catkin_LIBRARIES ${result_tem})
        else()
            list(APPEND catkin_LIBRARIES ${catkinlib})
        endif()
    else()
        list(APPEND catkin_LIBRARIES ${catkinlib})
    endif()
endforeach()

10 编译命令

catkin_make -DCMAKE_TOOLCHAIN_FILE=/$filepath/rostoolchain.cmake