32-bit OpenCV on OS X Lion? Possible? - c++

Question

I've been googling and trying for days now, trying to figure out how to get 32-bit OpenCV working on OS X Lion, but can just find 64-bit version.
So i have the following questions:
OpenCV libraries come in 32-bit or 64-bit arch, is that correct?
How do I get 32-bit OpenCV working on Lion? I've trying the following ways:
- Install OpenCV via MacPorts: nope, MacPorts installs a 64-bit version.BI removed OpenCV and MacPorts.
Install OpenCV 2.4.1 via Homebrew, using the following command:
brew install opencv --build32
but looks like they are 64-bit too. Removed OpenCV and Homebrew.
Install OpenCV 2.4.1 by myself using standard unix makefiles. Nope, they still look like 64-bit.
I've written "they look like 64-bit" because i have to replace OpenC in a Xcode project made under OS X Snow Leopard, targeted for 32-bit Mac, and I always get tons of errors like:
ld: warning: ignoring file /usr/local/Cellar/opencv/2.4.1/lib/libopencv_calib3d.2.4.1.dylib, file was built for unsupported file format which is not the architecture being linked (i386)
so i suppose that the OpenCV stuff is 64-bit. If i force the project to run in 64-bit, it rubs but doesn't work properly and gets stuck.
Is there a standard way to check if my OpenCV libraries are 64-bit or 32-bit?
Where can i get 32-bit OpenCV?

Answer 1

Solved the problem.
Recap: it is possible to have 32-bit OpenCV libraries on 64-bit Mac OSX Lion.
How?
Step 1: Download OpenCV 2.4.0
Step 2: Download and install CMake.
Step 3: Untar the OpenCV package.
Step 4: Make a separate directory inside the OpenCV package for building
mkdir build
cd build
cmake -G "Unix Makefiles" -D CMAKE_OSX_ARCHITECTURES=i386 -D CMAKE_C_FLAGS=-m32 -D CMAKE_CXX_FLAGS=-m32 ..
(this will force the 32-bit compile)
make -j8
sudo make install
Step 5: Enjoy!
For forther reference please visit Mac OS X OpenCV Port Page
Thanks all for putting me on the right track:
#karlphilip: I tried to do as you suggested, but without the make options the compile phase fails, because the architectures are incoherent.
#hamstergene: MacPorts got stuck after the new installation, maybe I have some remains of the older install :( (strange, i followed the official instrusctions to remove it).
#Adrien: That's what I've done, but i had to merge 2 approaches :)

Answer 2

I ve had a hard time configuring OpenCv libraries on a number od different OSs. Turns out that the thing is auto-generating a sample project and then bulding business logic inside it.
See the installation instructions here

Answer 3

The web site of the OpenCV project has been significantly upgraded in the last year.
A new tutorial section is avaiable, i was able to install OpenCV on my 32-bit core Mac OS Lion.
A very cool tutorial is also available at Sadeep's Tech Blog, covering an interesting range of details.
Hope this helps!

Answer 4

Here's something you can try: download OpenCV 2.4 sources and edit the CMakeLists.txt in the root directory. Around line 242 you will see:
# ----------------------------------------------------------------------------
# Path for build/platform -specific headers
# ----------------------------------------------------------------------------
set(OPENCV_CONFIG_FILE_INCLUDE_DIR "${CMAKE_BINARY_DIR}/" CACHE PATH "Where to create the platform-dependant cvconfig.h")
add_definitions(-DHAVE_CVCONFIG_H)
ocv_include_directories(${OPENCV_CONFIG_FILE_INCLUDE_DIR})
below the add_definitions() call, add this one:
add_definitions(-m32)