windows/linux/osx,intel/amd,desktop/laptop/pad

I am interested in different platforms. Thus, I spent a day on googleing related information. In order not to waste such time, I decide to write these down.

windows/linux/osx

windows is best optimized on the same hardwares.

I can finish all the same tasks on those OS. They are transparent in terms of software to me. So I am more interesting hardware optimizations, especially on graphics. I thought osx has some magic on optimizations so that they can be overpriced. But, I can not find any evidence to support my hypothesis. In stead, main stream games are optimized for windows at the first place. Although osx versions may catch up years later, they will not do better. Based on my own experience, my windows works smoother than my linux on the same laptop. Even on science computation, windows versions are a little faster, at least no worse. So far, I would say, windows are optimized best, based on the hardwares(based on hackintosh or the same level mac).

intel/amd

amd is never a good solution on desktops, for price, power consuming, or performance. Maybe it is good for laptop in terms of price.

I have no amd chips to test, so all the following comparisons are from google. Cpu of amd seems really sucks nowadays.A saying is that, A10 can only reach i3 for daily use. GPU is better, maybe A10 can match 630. As a result, A10 ($130 bundle) seems a better solution than i3 ($180 bundle) + 630. However, i3+630 level is not for gamers. I would like go i5/i7($250 bundle) + 650ti ($130) at least. A10 can crossfire with 6xxx cards. Higher level cards work better standalone. Also A10 is said to consume more power.

For laptops, the story is a little difference.If you focus on battery life, go macbooks. Nothing can bit them so far. If you pursuit performance, you will get a big box, as heavy as a desktop, with twice of its prices. Neither of them is my target. I am think about a cheap laptop which can handle basic games like WoW. CPU is never my bottle neck. core 2 duo can handle such games without any problems.We assume A10 = i3 + 630m in laptops. A laptop with 630m or above will cost $700 usually and will not consume any less power. A10 ones might cost $400. Also, the coming Kaveri A10 will have unified memory for GPU and CPU, which will benefit GPU computing. If you have a tight budget, A10 laptop may be good choice.

desktop/laptop/pad

powerful desktop + light laptop/pad

Desktops are much powerful than laptops. It is proved by data and my feeling. You will pay a lot to make the performance of a laptop to match that of a desktop. Even if you match the performance, you probably get a large, heavy, and hot laptop, and you need pay more to improve the mobility. My ideal solution is, getting a powerful desktop (if I really need one), and carrying a very light laptop, like yoga2 or air, or even a pad with bluetooth keyboard.

eclipse ndk resolve problem

eclipse seem not to resolve includes automatically. I just add those path manually. If adding them does not work, you can remove all the .* configures and import the clean project and add native code again. At least it works for me.

jni
/usr/lib/jvm/java-7-openjdk/include/

clang(I use clang, you can replace it with gcc 4.8)
/opt/android-ndk/toolchains/llvm-3.3/prebuilt/linux-x86_64/lib/clang/3.3/include/

libc++(I use libc++, you can replace it with gnustl)
/opt/android-ndk/sources/cxx-stl/llvm-libc++/libcxx/include/

platform specific includes (such as GLES2)
/opt/android-ndk/platforms/android-19/arch-arm/usr/include/

extra includes(such as eigen3 or boost)
/path/to/your/include


Here is my include path config export

includes.xml

<?xml version="1.0" encoding="UTF-8"?>
<cdtprojectproperties>
<section name="org.eclipse.cdt.internal.ui.wizards.settingswizards.IncludePaths">
<language name="c,cpp">
<includepath>/usr/lib/jvm/java-7-openjdk/include/</includepath>
<includepath>/opt/android-ndk/toolchains/llvm-3.3/prebuilt/linux-x86_64/lib/clang/3.3/include/</includepath>
<includepath>/opt/android-ndk/sources/cxx-stl/llvm-libc++/libcxx/include/</includepath>
<includepath>/opt/android-ndk/platforms/android-19/arch-arm/usr/include/</includepath>
<includepath>/home/jesse/local/android_toolchain/include</includepath>

</language>
</section>
<section name="org.eclipse.cdt.internal.ui.wizards.settingswizards.Macros">
<language name="c,cpp">

</language>
</section>
</cdtprojectproperties>

qt 5.2 opengl

It is quite frustrating. I can never get hellogl_el2 running with qt 5.2. openglunderqml works though.

I thought it might have sth to do with my old tegra tablet. I added -mtune=cortex-a9 -march=armv7-a -mhard-float -mfloat-abi=softfp -mfpu=vfpv3-d16 to qt building. I tested within eclipse. These parameters worked. And qt building seemed to take those. However, I still had no luck with hello_es2 demo. Maybe I have to stay on 5.1.1.

qt 5.2 SIGILL old devices

Qt 5.1 works for me out of box, but 5.2 does not. I always got SIGILL error on my doom. I googled and got only one piece of information. It is kind of neon related. Neon is some optimization features on latest devices. I disabled it with --no-neon and recompiled. Everything works fine again. Cheers!

qt 5.1.1, android, and tricks

Update, qt 5.2 works fine with build-tools r19. Tested with prebuilt qt, both on win8.1 and archlinux. Some old demos do not run. Bad news is the qt 5.2 I compiled from source did not work.

I finally got hellogl_es2 demo to run, after 3 days trying. So far it works on my archlinux. I guess I can make it work on win8.1.

Qt is not that ready for android in my option, at least 5.1. I am not sure about the coming 5.2. There are too many tricks. You need to get right versions of jdk, jre, apache-ant, android-sdk, android-ndk, and so on.

I try to list my settings as detailed as possible.

archlinux 64bit rolling updated.
offical package:
extra/jdk7-openjdk 7.u45_2.4.3-1
extra/jre7-openjdk 7.u45_2.4.3-1
extra/apache-ant 1.9.2-3

aur package:
android-armv7a-eabi-system-image-15 4.0.4_r02-2
android-armv7a-eabi-system-image-19 4.4_r01-1
android-ndk r9b-3
android-platform-10 2.3.3_r02-2
android-platform-11 3.0_r02-2
android-platform-15 4.0.4_r03-1
android-platform-16 4.1.2_r04-1
android-sdk r22.3-1
android-sdk-platform-tools r19-1
android-udev 67-1
(archlinux split sdk into small package, you can also install and manage them through the android-sdk interface)

custom package:
android-qt5 5.1.1-1(I compile qt 5.1.1 for android from source)
android-sdk-build-tools-18.0.1 r18.1.1-1(critical part, latest r19 is not supported by QT5.1. You will have build.xml error with r19)

win 8.1
Make jdk, jre, apache-ant, android-sdk, and ndk up to date.
In the android package managing interface, remove build-tools r19, install r18.1.1.
Double check your system environment variables, ANT_HOME and JAVA_HOME.
If ant works, qt for android should work out of box via qt-creator.

NDK and c++11 and GPL issue

According to "https://vilimpoc.org/blog/2013/10/05/c11-support-on-android-with-g-4-8/", ndk supports c++11 very well with gcc 4.8 and gnustl_static. I also compile my code with clang3.3, it works so far. So I assume clang works as well.

Note that, modern c++11 works only with gnustl. stlport is free, but does not support c++11. At least, my c++11 can not compile without gnustl.

You could set up the environment manually with ndk-build or put them in your Application.mk like this

APP_STL := gnustl_static
APP_ABI := armeabi
NDK_TOOLCHAIN_VERSION := clang
#NDK_TOOLCHAIN_VERSION := 4.8
APP_CPPFLAGS += -std=c++11

There is a little GPL license trick here. gnustl is with GPL. I am to lazy to read the license line by line. So, correct me if I am wrong. To my understanding, you should be fine with static link to gnustl. This means your stuff has not to be GPL via only static linking to gnustl, due to GPLv3 run time exception. However, you would better not use dynamic link to it.

NDK extrenal libs

After googled a lot, I figured out how to include existing prebuilt libs.

You have to add local modules (static or shared), and let your main module to call them in the android.mk.


#Here is the format for static libs. The shared ones work in the similar way.
#I use libpng as an example

include $(CLEAR_VARS)
LOCAL_MODULE := libpng
LOCAL_SRC_FILES := PATH/TO/YOUR/LIB/libpng.a
LOCAL_EXPORT_C_INCLUDES := PATH/TO/YOUR/INCLUDE
include $(PREBUILT_STATIC_LIBRARY)

#call it in your main module

include $(CLEAR_VARS)

LOCAL_C_INCLUDES := $(ANDROID_TOOLCHAIN)/include/
LOCAL_C_INCLUDES += $(ANDROID_SYSROOT)/include/

LOCAL_MODULE := YourModuleName
LOCAL_CFLAGS := -Wall -Wextra
LOCAL_CPPFLAGS += -std=c++11
LOCAL_SRC_FILES := YourModule.cpp

#add your external static modules
LOCAL_STATIC_LIBRARIES := libpng
LOCAL_LDLIBS := -llog -lGLESv2 -lEGL -landroid

include $(BUILD_SHARED_LIBRARY)