Building PCL for Android - android

Does anyone have instructions for building the Point Cloud Library (PCL) for Android? I found a few superbuilds of PCL that claim to be able to build PCL and its dependencies. I tried the superbuild from http://www.hirotakaster.com/weblog/how-to-build-pcl-for-android-memo/. I'm using Ubuntu 14.10, Android 19, NDK r10d, and PCL 1.6.0, but I'm willing to use any versions. I'm also using the terminal for compiling. For Android hardware, I'm using a Project Tango.
I tried using android-cmake (http://code.google.com/p/android-cmake/), but I'm not sure how to build the proper toolchain. I continually receive the error "Could not find any working toolchain in the NDK. Probably your Android NDK is broken." I get this error with plain cmake and ccmake, too.
Does anyone have any detailed instructions for building PCL for Android (e.g., a bash script or terminal instructions)? Or, does anyone have a link to pre-built libraries?

(Caveat Emptor: This is not a long term solution)
I was able to get past the CMAKE error by editing the cmake file
pcl-superbuild/toolchains/toolchain-android.cmake
These two changes should get past the errors mentioned above:
set( ANDROID_NDK_HOST_SYSTEM_NAME "linux-x86" ) # Line 468
Should be
set( ANDROID_NDK_HOST_SYSTEM_NAME "linux-x86_64" )
This will generate another error, unless you change the following line (Line 1023)
if( ANDROID_NDK_RELEASE STRGREATER "r8" ) # r8b
Should be
if( ANDROID_NDK_RELEASE STRGREATER "r10" ) # r8b
The first change adds _64 to x86_64. The second adds compatibility for r10d.
This doesn't fix all of the errors though, because BOOST threads don't place nicely with GCC 4.6+. Implement the patch shown at this link (https://svn.boost.org/trac/boost/ticket/6165).
Again, that still doesn't fix all of the errors. (I haven't figured out why this is needed yet, math.h shouldn't need std::). In the file,
pcl-superbuild/CMakeExternals/Source/pcl/common/include/pcl/pcl_macros.h
Edit lines 99-102:
# define pcl_isnan(x) isnan(x)
# define pcl_isfinite(x) isfinite(x)
# define pcl_isinf(x) isinf(x)
They should be:
# define pcl_isnan(x) std::isnan(x)
# define pcl_isfinite(x) std::isfinite(x)
# define pcl_isinf(x) std::isinf(x)
PCL still generates many warnings, but at least it compiles (so far)
**EDIT: **
This doesn't get you all the way (unfortunately) because the boost libraries don't play well with C++11.
To fix this, download boost 1.55 from http://sourceforge.net/projects/boost/files/boost/1.55.0/, and overwrite the boost directory
pcl-superbuild/CMakeExternals/Source/boost/boost_1_45_0
(This directory gets created when you run make for the first time).
Next, modify
pcl-superbuild/CMakeExternals/Source/boost/CMakeLists.txt
and find the line:
file(GLOB lib_srcs ${boost_root}/libs/filesystem/v2/src/*.cpp)
replace it with
file(GLOB lib_srcs ${boost_root}/libs/filesystem/src/*.cpp)
That's as far as I've gotten

this link helps a lot, you can take a look. I also left some comments there..
http://www.hirotakaster.com/weblog/how-to-build-pcl-for-android-memo/
for compile pcl 1.6 with ndk r10d, you need to replace toolchain-android.cmake with the toolchain from opencv library

I built PCL and its dependencies using Ubuntu 14.10, 32-bit. I also had to use NDK r8c, 32-bit. The key to building Hirotakaster's superbuild was using a 32-bit os.

I managed to compile your super build with Ubuntu 15.10 64-bit and NDK r10e. I changed the toolchain-android.cmake with the one from OpenCV. Then in common.hpp(found in /Source/pcl/common/include/pcl/common/impl) I had to add the following lines:
# include < math.h >
# define pcl_isnan(x) std::isnan(x)
# define pcl_isfinite(x) std::isfinite(x)
# define pcl_isinf(x) std::isinf(x)

Related

OpenCV for Android via Visual Studio to Unity

I tried to compile a .so library using Visual Studio 2019 along with OpenCV Android in order to use this library in Unity.
There are some answers on how to configure Visual Studio to use OpenCV Android (here or here) but none of these work for me. Below you can see my configurations.
Visual Studio 2019 (running on Windows 10)
android-ndk-r21e // also tried with android-ndk-r15c android-ndk-r16b and android-ndk-r17c
OpenCV Android 4.5.2 // also tried with OpenCV Android 4.0.0, 4.0.1 and 4.1.0
My settings in Visual Studio 2019 look as follows:
Configuration Properties
- General
Platform Toolset Clang 5.0 (also tried Clang 3.8 or GCC 4.9)
Configuration Type Dynamic Library (.so)
Target API Level Nougat 7.0 (android-24) (also tried different versions)
Use STL LLVM libc++ static library (c++_static) (also tried "GNU STL static library (gnustl_static)")
C/C++
- General
Additional Include Directories "Path to OpenCV_4_5_2_Android\sdk\native\jni\include"
Code Generation Enable C++ Exceptions "Yes(-fexceptions)"
Language C++17(-std=c++1z)
Precompiled Headers Not using Precompiled Headers
Linker
- General
Additional Library Directories Path to OpenCV_4_5_2_Android\sdk\native\libs\armeabi-v7a
- Input
Additional Dependencies Path to OpenCV_4_5_2_Android\sdk\native\libs\armeabi-v7a\libopencv_java4.so
My Source.cpp I try to compile is just a single function for testing purposes
#include <opencv2/core.hpp>
extern "C" float test(float a, float b)
{float c = a * b; return c;}
Which gives me the following errors:
E0035 #error directive: This constructor has not been ported to this platform
E0020 identifier "__fp16" is undefined
use of undeclared identifier 'ANDROID_LOG_INFO'
The ANDROID_LOG_INFO error can be fixed when I add #include "android/log.h" at the top of the file that throws this error. But the other two errors still remain.
I had the exact same issue as you (though I used c++ 11) with the exact same setup, and struggled for days. I believe the errors you're seeing (like me) are from arm_neon.h. Very oddly, I was able to just build (not run) the .so successfully, even with those errors (I say "errors" because if you look at arm_neon.h, others pop up), so try it. Maybe it's some kind of IntelliJ/Intellisense mistake more than anything else where it's catching false negatives from some other toolchain setup.
At the same time, I'm not 100% sure I was always able to build with that issue, so try these steps as well if you can't:
use OpenCV 4.0.1 with Android NDK 16rb. The NDK matters when it comes to OpenCV builds, and this is the only supposed match that I know of.
follow this tutorial from scratch: https://amin-ahmadi.com/2019/06/03/how-to-use-opencv-in-unity-for-android/
if the downloaded OpenCV android SDK is still giving trouble, build OpenCV from the source using his other tutorial here: https://amin-ahmadi.com/2019/02/03/how-to-build-opencv-4-x-for-native-android-development/
and then repeat step 2.
MAJOR EDIT:
OpenCV 4.5.2 needs to be treated differently because it no longer uses toolchains with gnu c++.
-When you build OpenCV from CMake, build with Android NDK 21e, and do not use the toolchain in OpenCV 4.5.2. Use the one inside the Android NDK's build folder (android-ndk-r21e\build\cmake).
-When you build your .so from Visual Studio 2019, do not use the GNU STL, use the LLVM. GNU c++ is no longer part of Android NDKs, and you need to cut it out of the process entirely.
-In the Linker Input, put the names of your library files (or file, if it's just the world one) in the Library Dependencies field, not the Additional Dependencies field.
-Everything else is the same as in those common tutorials.

Building capicxx-core-runtime for Android

We are trying to build capicxx-core-runtime for an ARM based platform running Android Pie. It's an open source IPC framework which is part of the GENIVI initiative by major automotive OEM's. Our AIM is to bring the IPC framework into our Android system.
The git repo is placed here https://github.com/GENIVI/capicxx-core-runtime.git
I am using the Android NDK version r17b and building using the following command to configure the cmake based build.
cmake -DCMAKE_TOOLCHAIN_FILE=/home/hp/downloads/android-ndk-r17b/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a -DANDROID_NATIVE_API_LEVEL=27 ../
When I compile using 'make', I see the individual cpp files are compiled, but I am getting following errors during linking as shown in the link below.What is the configuration that I may be missing.
Linker error log
the capicxx-core-runtime is building a shared library, so you need to resolve all of it's internal symbols, including the c++ runtime.
To quickly test this: edit the capicxx-core-runtime CMakeLists.txt to link the c++_shared runtime, line 130:
target_link_libraries(CommonAPI PRIVATE ${DL_LIBRARY} ${DLT_LIBRARIES})
becomes
target_link_libraries(CommonAPI PRIVATE ${DL_LIBRARY} ${DLT_LIBRARIES} c++_shared)
and rerun your cmake command and make command.
It seems that capicxx-core-runtime can be buildable now for Android (both NDK and AOSP) out the box, please see corresponding pull requests: https://github.com/GENIVI/capicxx-core-runtime/pulls?q=author%3Ankh-lab+
Also here is simple example for AndroidStudio how it could be used with vSOME/IP transport: https://github.com/nkh-lab/ndk-capi-hello-world

Compile c++ for android/iOS

I have to compile a library (library BPG from Bellard.org) to create a .so or a dll that I can use with android/iOS.
I'm working with Visual Studio. With some researches, I found the project "Visual C++ -> Cross Platform -> Shared Library (Android, iOS)". But I am totally lost and can't do anything.
The downloaded library is organised with some folders but Visual don't allow to make tree, all files are sorted by filters (one for header and one for sources). So I can't build, I have more than 300 errors, "can't open source file", "undefined variable"...
Secondly, the README file from project says :
The following packages need to be installed: mingw64-gcc mingw64-libpng mingw64-libjpeg-turbo mingw64-SDL mingw64-SDL_image yasm
I found installed for mingw 32 bits but no 64 bits so I don't know if build can perform. I don't know how to find the libraries.
So my question is, what is the best way to compile a C/C++ library for android/iOS ? And where can I find a tutorial for beginners ?
Thank you
I have worked as cross compiling engineer for several years. The most suitable IDE for you I think, is the CLion with CMake inside.
CMake is a tool which can cross-compile the C/C++ library into ios\android\linux\etc.. using only one config file: "CMakeList.txt".
The main task of CMake is to translate CMakeList.txt to Makefile on every platform and provide you the .a and .so files.
CLion is very powerful IDE in code editing and debugging.
Furthermore, Android needs JNI (or JNA if performance is not concerned) to wrap your c++ interfaces to java classes. Here I would recommend SWIG. SWIG is a tool to wrap C++ interfaces to other languages, that means, not only java on android you can support , other days your lib can also support python\tcl\Go\etc.
Which os are u using to build the lib? macOS or win ?
For iOS : .a file
For Android: .so file
First you should check the README file
Edit the Makefile to change the compile options (the default
compile options should be OK). Type 'make' to compile and 'make
install' to install the compiled binaries.
Use 'make -j N' where N is the number of CPU cores to compile faster.
The following packages must be installed: SDL-devel
SDL_image-devel yasm. It is recommended to use yasm version >= 1.3.0
to have a faster compilation.
Only a 64 bit target is supported because x265 needs it for bit
depths > 8.
check this to install SDL packages
https://wiki.libsdl.org/Installation

Using CrystaX with Qt to build android application: java.lang.UnsatisfiedLinkError

I am trying to build Qt application for android using Qt Creator. I use CrystaX NDK for android instead of goolge's one because I need to use boost libraries in my project, and, as CrystaX's official site says, it is comes with it.
I am using following versions of tools:
Qt Creator 3.4.2
Qt 5.5.0
CrystaX NDK 10.2.1
At first, I had to manually add libraries and headers paths in my .pro file, because it hasn't been found automatically. There was compiler error: can't locate libcrystax, there was some errors in source files about including boost headers. I've added following lines in my project file:
android {
INCLUDEPATH += $$NDK_ROOT/sources/crystax/include \
$$NDK_ROOT/sources/boost/1.58.0/include \
$$PWD/ssl
LIBS += -L"$$PWD/ssl" -lssl -lcrypto
LIBS += -L"$$NDK_ROOT/sources/crystax/libs/$$ANDROID_TARGET_ARCH"
ANDROID_EXTRA_LIBS = $$NDK_ROOT/sources/crystax/libs/$$ANDROID_TARGET_ARCH/libcrystax.so
ANDROID_PACKAGE_SOURCE_DIR = $$PWD/android
}
After rebuilding again, I've got an error (runtime error) that says libgnustl_shared requires libcrystax, but libcrystax is not loaded or something similar.
After searching the internet, I've found that it's happening because one library that requires another, is loading before it, and that second library, is not being searched for, at application directory, only in system paths.
I've found a workaround - to load required library manually. I copied default QtActivity.java into my project directory (android/src/.../QtActivity.java) to replace default one and added following code:
static {
System.loadLibrary( "crystax" );
}
After that I am not getting that error, but now I'm stuck with another one:
java.lang.UnsatisfiedLinkError: Cannot load library: reloc_library[1285]: 37 cannot locate '__aeabi_ldiv0'...
Is it possible to use Qt + CrystaX NDK for build android app? Am I doing it wrong way? Please, explain how to do it properly, if I've mistaken or if I misunderstood whole concept. Any help is appreciated.
This happens because you haven't linked with libgcc.a. I don't know how exactly your build system works (well, Qt's one), but generally, adding libgcc.a to the list of additional libraries should help:
ANDROID_EXTRA_LIBS = $$NDK_ROOT/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/lib/gcc/arm-linux-androideabi/4.9/libgcc.a
This line specify arm variant of libgcc.a; obviously, you should use proper one depending on ANDROID_TARGET_ARCH value.

How to Build CMake based project for Android/iOS using QtCreator

I have created a Non-Qt C++ (CMake) project using Qt, and I am able to build it using MinGW, MSVC compiler.
So in short, when I am opening my test project I can select the generators under Run CMake Window. I have issue with other platforms.
When I am trying to Add a kit for Android, there are no generators available in the list. I tried the same thing on Macbook, there also the same problem.
I need help on this issue, I couldn't get the proper steps to build the CMake based project for Android/iOS using QtCreator.
P.S. Installed CMake version is 3.2.1 and Qt Version is 5.5, I have installed Android SDK, NDK , and and Java
I would love to tell you "just check this box in the options dialog and it will work", but, unfortunately, there is no generator that you can use to build an Android/iOS project from a CMakeLists.txt file.
I found alternatives, in all cases, I don't think your have a chance to port a whole huge CMake-based project that used to work on Windows (with lots of libraries and 3rd party libraries) work on Android in less than a few days of work....;-)
Personnaly, I wrote a small CMake function generating the .pro file manually from my CMake scripts. It started small but is now huge and it's difficult to share it with you. But, basically, I started from this post on a Qt forum. It creates a simple .pro file that does not work that bad and then you can extend it for your own needs. I like this solution because I have full control on generated .pro file (mine can now build on PC, Android and iOS...but I had a hard time to have this fully work).
Apparently, there's also a way to add a Qt-android CMake support using this open source stuff: https://github.com/LaurentGomila/qt-android-cmake. But I never tried it. You may want to have a look to it. If it works, it may be more convenient that writting your own script generating .pro files. Apparently, it builds an Android apk using androidqtdeploy but without using QtCreator. There's also an iOS support.
Finally, the best may be to have CMake propose a QtCreator "generator" (it would generate .pro files, like CMake generates sln/vcproj files when using Visual Studio generator or makefiles for g++ generator....), but there is no such generator supported. I reported this to CMake team some time ago hoping they could fix that. I understood that there was and would be no plan to do that because CMake targets only "compilers" as "generators" and "QtCreator" is not really a "compiler", it's a "IDE" using external "compilers" to build (MinGW, MSVC, CLang, Android's NDK g++...). It's a shame because CMake known all your project information and could easily generate a .pro file....so, as, CMake is opensource, one may extend CMake with a custom QtCreator file generator...and share it with the whole world,it would be wonderful!
Hope this will help you!

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