compiling opencv 2.4 on a 64 bit mac in Xcode - opencv

Question

I have an opencv project that I've been developing under ubuntu 12.04, on a parellels VM on a mac which has an x86_64 architecture. There have been many screen switching performance issues that I believe are due to the VM, where linux video modes flip around for a couple seconds while camera access is made by the opencv application. I decided to moved the project into Xcode on the mac side of the computer to continue the opencv development. However, I'm not that familiar with xcode and am having trouble getting the project to build correctly there.
I have xcode installed.
I downloaded and decompressed the latest version of opencv on the mac, and ran: ~/src/opencv/build/cmake-gui -G Xcode .. per the instructions from willowgarage and various other locations.
This appeared to work fine (however I'm wondering now if I'm missing an architecture setting in here, although it is 64-bit intel in Xcode).
I then setup an xcode project with the source files from the linux project and changed the include directories to use /opt/local/include/... rather than the /usr/local/include/...
I switched xcode to use the LLVM GCC compiler in the build settings for the project
then set the Apple LLVM Dialog for C++ to Language Dialect to GNU++11 (which seems possibly inconsistant with the line above)
I'm not using a makefile in xcode, (that I'm aware of - it has its own project file...)
I was also running into a linker issue that looked like they may be resolved with the addition of this linker flag:
-lopencv_video
based on a similar posting here: other thread
however in that case the person was using a Makefile in their project.
I've tried adding this linker flag under "Other Linker Flags" in xcode build settings but still get build errors.
I think I may have two issues here, one with the architecture settings when building the opencv libraries with Cmake, and one with the linker flag settings in my project.
Currently the build error list looks like this:
Undefined symbols for architecture x86_64:
"cv::_InputArray::_InputArray(cv::Mat const&)", referenced from:
_main in main.o
"cv::_OutputArray::_OutputArray(cv::Mat&)", referenced from:
_main in main.o
"cv::Mat::deallocate()", referenced from:
cv::Mat::release() in main.o
"cv::Mat::copySize(cv::Mat const&)", referenced from:
cv::Mat::Mat(cv::Mat const&)in main.o
cv::Mat::operator=(cv::Mat const&)in main.o
"cv::Mat::Mat(_IplImage const*, bool)", referenced from:
_main in main.o
"cv::imread(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int)", referenced from:
_main in main.o
---SNIP---
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
Can anyone provide some guidance on what to try next?
Thanks,
Walt

Answer 1

steps to compile and run c++ opencv 2.4.4 on mac os x lion 10.7.5 with cmake 2.8.10 and xcode 4.6.1
EDIT: successfully tested with opencv 2.4.5 on mac os x mountain lion 10.8.3 and Xcode 4.5
Having the right tools
download opencv-unix from http://sourceforge.net/projects/opencvlibrary/files/ and untar it wherever
download cmake .dmg from http://www.cmake.org/cmake/resources/software.html and install it
i am assuming you have xcode 4.6 on os x lion which includes the ios sdk 6.1
go to xcode preferences to download and install the Command Line Tools so you have g++ etc.
Use cmake to compile opencv
go to the extracted opencv folder
create a build directory
mkdir build
cd build
cmake -D WITH_TBB=OFF -D BUILD_NEW_PYTHON_SUPPORT=OFF -D BUILD_FAT_JAVA_LIB=OFF -D BUILD_TBB=OFF -D BUILD_EXAMPLES=ON -D CMAKE_CXX_COMPILER=g++ CMAKE_CC_COMPILER=gcc -D CMAKE_OSX_ARCHITECTURES=x86_64 -D BUILD_opencv_java=OFF -G "Unix Makefiles" ..
make -j8
sudo make install
from the build folder, go to bin/ and run one of the tests
./opencv-test-photo
Create your own c++ opencv xcode project
fire up xcode and create a new xcode project
select Command Line Tool for the type of project under os x
open your project's build settings
under Architectures, set Architecture to 64-bit intel. also set Valid Architectures to x86_64
under Build Options, set Compiler for C/C++ to Default Compiler
under Search Paths, set Header Search Paths to /usr/local/include
also under Search Paths, set Library Search Paths to /usr/local/lib
under Apple LLVM compiler 4.2 - Language set C++ Standard Library to libstd++ (With OpenCV 2.4.6, Xcode 5, LLVM 5.0, and 10.8.5, set both language dialect and std library to "Compiler Default" instead)
Add the compiled opencv libraries to your project
go the the Build Phases tab next to Build Settings tab you were in
inside Link Binary With Libraries, click on the + sign and choose Add Other
hit the front slash / on your keyboard and enter /usr/local/lib
hit enter and select the libraries you want to use in your project
make sure you always select libopencv_core.2.4.4.dylib
hit enter and you will see the selected dylibs under your project
write some code
first lets organize the files, right click on your project blueprint icon and select New Group
name the new group opencv or whatever
drag the dylibs and drop them in that group
open main.cpp
copy code from any of the sample tests that came with opencv and paste it here
make sure all the required dylibs are added, for example, if you copied the opencv_test_stitching.cpp code into main.cpp, you will need to add the following libraries in the previous steps
libopencv_core.2.4.4.dylib
libopencv_highgui.2.4.4.dylib
libopencv_stitching.2.4.4.dylib
Cheers.