I installed OpenCV 4.5.2 using the Windows installer and when I looked in the apps folder, I couldn't find some apps (create_samples, train_cascade). So, I downloaded the code and I generated visual studio projects using CMake. After I built all those project, again, in the app folder there were no project files to build those apps.
I also run cmake . in an app directory, but this error came out:
CMake Warning (dev) in CMakeLists.txt:
No project() command is present. The top-level CMakeLists.txt file must
contain a literal, direct call to the project() command. Add a line of
code such as
project(ProjectName)
near the top of the file, but after cmake_minimum_required().
CMake is pretending there is a "project(Project)" command on the first
line.
This warning is for project developers. Use -Wno-dev to suppress it.
CMake Error at CMakeLists.txt:4 (ocv_add_application):
Unknown CMake command "ocv_add_application".
-- Configuring incomplete, errors occurred!
See also "C:/opencv/opencv-master/apps/createsamples/CMakeFiles/CMakeOutput.log".
this is the CMakeLists.txt file that I run:
file(GLOB SRCS *.cpp)
ocv_add_application(opencv_createsamples
MODULES opencv_core opencv_imgproc opencv_objdetect opencv_imgcodecs opencv_highgui opencv_calib3d opencv_features2d opencv_videoio
SRCS ${SRCS})
In all honesty, last time that I used CMake was 10 years ago and I really would like an hand to figure this out.
Thanks
STACK:
CMake 3.20.3
OpenCV 4.5.2
Python 3.9.5
Visual Studio 16.10.0
Wndows 10
I found out why this is happening. In opencv 4.5 (I didn't check other versions), the line in the cmake file that generate the solution for traincascade and createsamples, are explicitly commented out. This because building those apps will generate more than 600 errors! Let's hope this problem will be fixed soon.
from https://github.com/opencv/opencv/issues/13231
These apps has been disabled during legacy C API removal. Rewriting them
with C++ API was not an option because it is too easy to break them
and hard to test.
Also modern approaches via DNN provides much better results - just
compare OpenCV face detector with CascadeClassifier and DNN.
Related
I am getting error
Error C1007 unrecognized flag '-Ot' in 'p2'
but unable to find -Ot in the command line string of the project. Googling did not help. Anyone know what does that flag stand for ?
I had a similar issue on a project that I was compiling. It seems to be caused when MSVC 2017 linker tries to link a dependency library ".lib" to your project and it was compiled with Optimization flag /Ot enabled. That is why you can not see it on command line of your own project. You can try one of these actions.
Recompile your libs without /Ot enabled (Properties → C/C++ → Optimization → Favor Size or Speed → Neither), then recompile whole project.
Update MSVC 2017 toolchain to the latest one, which should be 14.14.26428. After updating, recompile your project. It is strange, but in my machine configuration, toolchain 14.13 couldn't link libraries compiled with newer toolchains and /Ot enabled.
Both solutions worked in my case, but I ended up using number 2.
Just for future reference to this error msg:
I got this error with no -Ot option set, the error message was misleading. Turned out that I tried to build a project with a 140 toolset (VS2015 - forgot to upgrade to 141) with .dll and .lib dependencies already built with 141 (VS2017). After updating the toolset to 141 the project could be built.
You should find this flag in the Optimization property page of your project.
-Ot (/Ot) option is the Favor Fast Code flag (Attempts to offer improvements in execution time over space)
According to the Microsoft Visual C++ Documentation (https://learn.microsoft.com/en-us/cpp/build/reference/os-ot-favor-small-code-favor-fast-code),
If you use /Os or /Ot, then you must also specify /Og to optimize the
code.
Happened to me while building nmap. Executables did not have /GL, while libnetutil did. Removing /GL from libnetutil fixed it. Or, if possible (and desired), align /GL to all dependent targets (lib, dll/exe).
The android ndk supplied by google is unable to compile call to c++11 functions such as std::to_string() and std::stoul etc. {I had tried it in r10b one from the official site}. So the suggestion in SO was to try crystax NDK. I have downloaded and placed the root folder next to the google's NDK. All I changed in my root CMakeLists.txt file was:
from:
set(PLATFORM_PREFIX "/some-path/android-ndk-r10b/platforms/android-19/arch-arm")
set(PLATFORM_FLAGS "-fPIC -Wno-psabi --sysroot=${PLATFORM_PREFIX}")
set(CMAKE_CXX_FLAGS "${PLATFORM_FLAGS} -march=armv7-a -mfloat-abi=softfp -mfpu=neon" CACHE STRING "")
To:
set(PLATFORM_PREFIX "/some-path/android-ndk-r8-crystax-1/platforms/android-14/arch-arm")
set(PLATFORM_FLAGS "-fPIC -Wno-psabi --sysroot=${PLATFORM_PREFIX}")
set(CMAKE_CXX_FLAGS "${PLATFORM_FLAGS} -march=armv7-a -mfloat-abi=softfp -mfpu=neon" CACHE STRING "")
and cmake command-line from:
cmake .. -DCMAKE_CXX_COMPILER=/some-path/android-ndk-r10b/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++ -DCMAKE_C_COMPILER=/some-path/android-ndk-r10b/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc -DANDROID_BUILD=ON -DANDROID_NDK_ROOT=/some-path/android-ndk-r10b
To:
cmake .. -DCMAKE_CXX_COMPILER=/some-path/android-ndk-r8-crystax-1/toolchains/arm-linux-androideabi-4.7/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++ -DCMAKE_C_COMPILER=/some-path/android-ndk-r8-crystax-1/toolchains/arm-linux-androideabi-4.7/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc -DANDROID_BUILD=ON -DANDROID_NDK_ROOT=/some-path/android-ndk-r8-crystax-1
ie., changed from normal ndk to crystax-ndk. The program was compiling fine previously till it tried to compile a file with call to std::to_string() etc. But after the change Cmake gives an error that it is unable to compile a simple test program because:
/some-path/android-ndk-r8-crystax-1/toolchains/arm-linux-androideabi-4.7/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.7/../../../../arm-linux-androideabi/bin/ld:
error: cannot find -lcrystax
I can see libcrystax.a and .so in directorie:
/some-path/android-ndk-r8-crystax-1/sources/crystax/libs/armeabi-v7a
I tried adding link_directories("path-to-above") right at the beginning of the CMakeLists.txt file too, but that didn't solve it either.
It should find it there (after i supply the --sysroot etc above) just like the normal ndk. So how should this be solved ? Any other cmake variable to be set or something ?
I don't know how your cmake-based build system works, but actually if you properly add path /some-path/android-ndk-r8-crystax-1/sources/crystax/libs/armeabi-v7a to linker search paths, it should find libcrystax and link with it successfully.
Please note that NDK have several parts separated each from other - i.e. sysroot, libcrystax, C++ library - all are separated. It is done to work with NDK build system which offer some flexibility choosing C++ standard library implementation, and NDK build system know where to find all of them. In your case this approach is not so good so I suggest you first make standalone toolchain, which contains all things assembled together. In other words, it would be classic cross-compile toolchain which contains sysroot, libcrystax and GNU C++ standard library in places known to compiler/linker without passing of any additional options.
To create such toolchain, cd to NDK root directory and run the following command:
./build/tools/make-standalone-toolchain.sh --system=linux-x86_64 --toolchain=arm-linux-androideabi-4.7 --platform=android-14 --install-dir=$HOME/arm-linux-androideabi
Then use $HOME/arm-linux-androideabi as full standalone toolchain for your cmake-based build system.
Please note, however, that application built with CrystaX NDK r8 will not run on newest Android 5.0 due to changes in Bionic (libc). Previous Android versions (<=4.4) are all fine. We fixed that issue (and many others) in upcoming r10 release which is on final testing stage. In the meantime you could adopt your project to our r8 release and quickly switch to r10 when it done - the same approach will work with r10 as well as with r8.
I'm trying to build LLVM/Clang on Windows 7 with Microsoft C++ 2013. Building LLVM spat out a few error messages along the way but mostly seemed to be succeeding and did end up creating a folder full of exe's so that part seems to have worked. When I try to build Clang:
C:\clang>\CMake\bin\cmake.exe ..\clang-3.4 -DCLANG_PATH_TO_LLVM_BUILD=/llvm
CMake Error at CMakeLists.txt:29 (message):
Please set CLANG_PATH_TO_LLVM_BUILD to a directory containing a LLVM build.
And I get the same error message whether I omit CLANG_PATH_TO_LLVM_BUILD, define it in CMakeLists.txt or an environment variable instead of the command line, set it to possibly relevant subdirectories of /llvm etc.
What am I missing?
You're not following the instructions on this page correctly, under "Using Visual Studio". You will end up with
/
/llvm
/llvm/CMakeLists.txt
/llvm/tools/clang
/llvm/tools/clang/CMakeLists.txt
Step 4, repeated here for clarity:
Run CMake to generate the Visual Studio solution and project files:
cd ..\.. (back to where you started)
mkdir build (for building without polluting the source dir)
cd build
If you are using Visual Studio 2012: cmake -G "Visual Studio 11" ..\llvm
That last bit needs to be run from inside the VS Command Prompt, but you seem to have that sorted out. You can also generate "NMake makefiles" if you don't use the IDE to build. Anyways, the point is that you should call cmake on the toplevel CMakeLists.txt file, not on the clang one directly. Clang will be built as part of the build process. You can even add libc++ and compiler-rt to the llvm/projects directory to have these built automatically on platforms that support them.
What you are doing is building clang "out of tree". Which is possible and even supported, but only really useful in certain circumstances. You'll need a previously built build of LLVM in some directory. You then set CLANG_PATH_TO_LLVM_BUILD to the directory containing the built LLVM files (this is not the source directory). But as I said, that's making things needlessly difficult.
I am currently attempting to transition a CMake project from Linux to Windows that is dependent on OpenCV, but I'm having trouble linking the libraries to the executable.
I've posted the approximate CMakeLists.txt file below with some private stuff left out:
project(my_project_name)
cmake_minimum_required(VERSION 2.8)
SET(CMAKE_CXX_FLAGS "-g -Wall")
SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/../bin)
FIND_PACKAGE(OpenCV REQUIRED)
IF(NOT OpenCV_FOUND)
MESSAGE(FATAL_ERROR "OpenCV not found")
ENDIF()
SET(PROJECT_HDRS
#headers here
)
SET(PROJECT_SRCS
#sources here
)
add_executable(${PROJECT_NAME} ${PROJECT_SRCS})
TARGET_LINK_LIBRARIES(${PROJECT_NAME} ${OpenCV_LIBS})
This CMakeLists.txt file works just fine on Linux, but has trouble linking on Windows. My first instinct was that it was a bad install of OpenCV? Here are the approximate steps I used while installing OpenCV
Download OpenCV 2.4.3 executable (a self-extracting archive)
Extract to some directory
Use CMake-Gui to configure and generate OpenCV.sln
Open in Visual Studio C++ 2010 Express and build the ALL_BUILD project in Debug and Release configurations
Build the INSTALL project
When I try to build my own project, I get back the errors "undefined reference to 'cv::waitKey(int)' errors, which makes me think that it's a linker issue. I've attempted pointing to the .lib files directly, such as:
target_link_libraries(${PROJECT_NAME} C:/someDirectory/opencv_core243.lib)
but I still get back the same errors.
I've also attempted the methods in described in these StackOverflow threads:
here and here.
I apologize beforehand if I'm missing something obvious, but this is more or less the first time I've developed on windows and I'm running out of ideas.
to my knowledge the problem is that visual studio2010 or vc++2010 comes with .net framework 4.5
Downgrade it to .net framework4 (i.e. uninstall .net 4.5 and install 4.0).
That would solve the problem...
I hit my head to my table solving the above problem..
or else
patch the visual c++ with new Service pack
it´s a little bit late but... let´s go
for me this tutorial was perfect
http://kevinhughes.ca/tutorials/opencv-install-on-windows-with-codeblocks-and-mingw/
I am currently digitizing old VHS cassettes. For post-processing, I would like to implement a custom algorithm with C++ & OpenCV. I have already implemented a promising prototype in Matlab, but it can only process single images (reading / writing video files is not possible in my version (R2010a); also, Matlab is far too slow).
Sadly, I am - over and over again - stuck with CMake. Though I wonder ... this can't be so difficult. I have often had problems with CMake, so I will go into a lot of detail here. I hope that you can not only point out to me what I am doing wrong here, but give general advices towards my usage of CMake as well. Maybe I am doing it all wrong, I don't know.
Here is what I've done so far:
I have downloaded the OpenCV 2.3.1 superpack from sourceforge. The superpack contains OpenCV source code, includes and - most importantly - the .lib and .dll files for all major platforms. For this reason, I need not build OpenCV myself. It is already done. I need only use/link it.
I installed (i.e. extracted to) the superpack in C:\dev\vs2010sp1_win32\opencv\2.3.1.
I have renamed C:\dev\vs2010sp1_win32\opencv\2.3.1\OpenCVConfig.cmake.in to OpenCVConfig.cmake.
I have created a folder for my project C:\dev\VhsDejitterizer with the following structure:
VhsDejitterizer/
CMakeLists.txt (A)
src/
CMakeLists.txt (B)
libvhsdejitter/
CMakeLists.txt (C)
vhsdejitter/
util.h
util.cpp
main/
CMakeLists.txt (D)
main.cpp
Here are the contents of the individual CMakeLists.txt files.
/CMakeLists.txt (A)
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
PROJECT("VhsDejitterizer")
CMAKE_POLICY(SET CMP0015 OLD)
FIND_PACKAGE(OpenCV REQUIRED
NO_MODULE
PATHS "C:/dev/vs2010sp1_win32/opencv/2.3.1"
NO_DEFAULT_PATH)
ADD_SUBDIRECTORY("src")
/src/CMakeLists.txt (B)
ADD_SUBDIRECTORY("libvhsdejitter")
ADD_SUBDIRECTORY("main")
/src/libvhsdejitter/CMakeLists.txt (C)
UNSET(source_files)
FILE(GLOB_RECURSE source_files "*.h" "*.cpp")
ADD_LIBRARY(libvhsdejitter STATIC ${source_files})
TARGET_LINK_LIBRARIES(libvhsdejitter ${OpenCV_LIBS})
UNSET(source_files)
/src/main/CMakeLists.txt (D)
UNSET(source_files)
FILE(GLOB_RECURSE source_files "*.h" "*.cpp")
ADD_EXECUTABLE(main ${source_files})
TARGET_LINK_LIBRARIES(main libvhsdejitter ${OpenCV_LIBS})
UNSET(source_files)
Configuring and generating the Visual Studio .sln (...) files works well. In fact, I am not getting a single warning or error:
Configuring done
Generating done
However, my attempt to build the 'main' project in Visual Studio fails:
1>------ Build started: Project: main, Configuration: Debug Win32 ------
1>Build started 04.04.2012 14:38:47.
1>InitializeBuildStatus:
1> Touching "main.dir\Debug\main.unsuccessfulbuild".
1>CustomBuild:
1> All outputs are up-to-date.
1>ClCompile:
1> main.cpp
1>LINK : fatal error LNK1104: cannot open file '#CMAKE_LIB_DIRS_CONFIGCMAKE#/libopencv_gpu.so.#OPENCV_VERSION##OPENCV_DLLVERSION##OPENCV_DEBUG_POSTFIX#.lib'
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:00.59
========== Build: 0 succeeded, 1 failed, 2 up-to-date, 0 skipped ==========
Further details:
Operating system: Windows 7 Pro 64-bit
IDE: Visual Studio 2010 SP1
CMake version: 2.8.4
Target platform (i.e. what am I compiling/building for): Windows 32-bit
My questions:
How do I successfully build the 'main' project? I.e. how to fix that error?
What are these #VARIABLE_OR_SOMETHING#? I have tried to find out where they come from, and they seem to be set up in OpenCVConfig.cmake. But how are they supposed to work? Are they supposed to be evaluated by Visual Studio at "build-time"? If so, how are they evaluated?
You have probably noticed that I have set up quite a sophisticated folder structure. Do you have any advice on this? How do you organize your libraries and projects? Are there best-practices? Where are they documented?
Thank you and best regards, Robert
These variables are probably related to CMake's configure_file command, which allows you to specify a parameterised template document (typically with the extension ending in .in) and you can substitute CMake variables into the file to create it. They are evaluated at the time of the configure_file call, which happens when running CMake. I think what's happening is that there will be a parent CMake script to the one that you've taken which will configure that file with the contents of those variables and then use it in an add_subdirectory call. I would suggest checking for any readme that describes the top level run process (or any file which defines those variables then substitute them manually).
I have fixed it now. I think I can safely say that the whole mess was not my fault. Sorry for answering my own question.
Here is what I tried first (of course, this did not work for me, but it might work for others):
As Martin Foot pointed out in his answer, the *.in files are templates which are supposed to be filled out with proper values during a CMake configuration. However, I am using the OpenCV superpack, which includes all the binaries. For this reason I have, at no point, performed such a configuration step, because I assumed this would only be necessary if you wanted to compile something.
However, it seems that - even if you're using the superpack with prebuilt binaries - you have to configure the project in order to get your OpenCVConfig.cmake generated. Vadim Pisarevsky has stated that in the OpenCV bug tracker.
For some reason, this didn't work for me. I started up the Cmake GUI as usual, pointed it to the OpenCV directory and hit "Configure". I even hit "Generate" out of desperation. Yet, no OpenCVConfig.cmake appeared.
So I had to go on further ...
This is what actually helped:
In a recently filed bugreport related to OpenCVConfig.cmake, Sergiu Dotenco pointed out "that the currently provided OpenCVConfig.cmake is pretty fragile" etc. etc. Fortunately, Sergio has also provided a custom FindOpenCV.cmake script. By using his script I have finally been able to generate a working Visual Studio solution.
By the way, this is my current top-level CMakeLists.txt:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
PROJECT("VhsDejitterizer")
SET(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake-modules" ${CMAKE_MODULE_PATH})
SET(OPENCV_ROOT_DIR "C:/dev/vs2010sp1_win32/opencv/2.3.1")
#SET(OPENCV_USE_GPU_LIBS ON)
FIND_PACKAGE(OpenCV REQUIRED)
ADD_SUBDIRECTORY("src")
I have installed Sergio's FindOpenCV.cmake script in a new cmake-modules/ subfolder of the project. It is also important to note that I am using (as opposed to my original setup, where I used the "config mode") the minimal FIND_PACKAGE variant ("module mode"). Only if the minimal variant is used, CMake is looking for Find<package-name>.cmake scripts in the CMake module path. See the CMake documentation for FIND_PACKAGE.
I have also found this guide, which is about how to properly use CMake if you're a library developer: http://www.vtk.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file
I have fixed it now. I think I can safely say that the whole mess was not my fault. Sorry for answering my own question.
You fixed it?
I am having the same problem, and I followed your solution but it did not work.
When CMake executed the command
FIND_PACKAGE( OpenCV REQUIRED )
It would output:
One or more OpenCV components were not found:
calib3d
contrib
core
features2d
flann
highgui
imgproc
legacy
ml
objdetect
video
CMake Error at C:/Program Files/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:91 (MESSAGE):
Could NOT find OpenCV (missing: OPENCV_CALIB3D_LIBRARY
OPENCV_CONTRIB_LIBRARY OPENCV_CORE_LIBRARY OPENCV_FEATURES2D_LIBRARY
OPENCV_FLANN_LIBRARY OPENCV_HIGHGUI_LIBRARY OPENCV_IMGPROC_LIBRARY
OPENCV_LEGACY_LIBRARY OPENCV_ML_LIBRARY OPENCV_OBJDETECT_LIBRARY
OPENCV_VIDEO_LIBRARY) (found version "2.3.1")
Finally, I used the commands
include_directories
TARGET_LINK_LIBRARIES
to include all necessary directories or files, and it works, in a awkward way!