mirror of
https://git.do.srb2.org/KartKrew/Kart-Public.git
synced 2024-11-18 02:31:57 +00:00
464 lines
20 KiB
Markdown
464 lines
20 KiB
Markdown
Android
|
|
================================================================================
|
|
|
|
Requirements:
|
|
|
|
Android SDK (version 12 or later)
|
|
http://developer.android.com/sdk/index.html
|
|
|
|
Android NDK r7 or later
|
|
http://developer.android.com/tools/sdk/ndk/index.html
|
|
|
|
Minimum API level supported by SDL: 10 (Android 2.3.3)
|
|
Joystick support is available for API level >=12 devices.
|
|
|
|
================================================================================
|
|
How the port works
|
|
================================================================================
|
|
|
|
- Android applications are Java-based, optionally with parts written in C
|
|
- As SDL apps are C-based, we use a small Java shim that uses JNI to talk to
|
|
the SDL library
|
|
- This means that your application C code must be placed inside an Android
|
|
Java project, along with some C support code that communicates with Java
|
|
- This eventually produces a standard Android .apk package
|
|
|
|
The Android Java code implements an "Activity" and can be found in:
|
|
android-project/src/org/libsdl/app/SDLActivity.java
|
|
|
|
The Java code loads your game code, the SDL shared library, and
|
|
dispatches to native functions implemented in the SDL library:
|
|
src/core/android/SDL_android.c
|
|
|
|
Your project must include some glue code that starts your main() routine:
|
|
src/main/android/SDL_android_main.c
|
|
|
|
|
|
================================================================================
|
|
Building an app
|
|
================================================================================
|
|
|
|
For simple projects you can use the script located at build-scripts/androidbuild.sh
|
|
|
|
There's two ways of using it:
|
|
|
|
androidbuild.sh com.yourcompany.yourapp < sources.list
|
|
androidbuild.sh com.yourcompany.yourapp source1.c source2.c ...sourceN.c
|
|
|
|
sources.list should be a text file with a source file name in each line
|
|
Filenames should be specified relative to the current directory, for example if
|
|
you are in the build-scripts directory and want to create the testgles.c test, you'll
|
|
run:
|
|
|
|
./androidbuild.sh org.libsdl.testgles ../test/testgles.c
|
|
|
|
One limitation of this script is that all sources provided will be aggregated into
|
|
a single directory, thus all your source files should have a unique name.
|
|
|
|
Once the project is complete the script will tell you where the debug APK is located.
|
|
If you want to create a signed release APK, you can use the project created by this
|
|
utility to generate it.
|
|
|
|
Finally, a word of caution: re running androidbuild.sh wipes any changes you may have
|
|
done in the build directory for the app!
|
|
|
|
|
|
For more complex projects, follow these instructions:
|
|
|
|
1. Copy the android-project directory wherever you want to keep your projects
|
|
and rename it to the name of your project.
|
|
2. Move or symlink this SDL directory into the <project>/jni directory
|
|
3. Edit <project>/jni/src/Android.mk to include your source files
|
|
4. Run 'ndk-build' (a script provided by the NDK). This compiles the C source
|
|
|
|
If you want to use the Eclipse IDE, skip to the Eclipse section below.
|
|
|
|
5. Create <project>/local.properties and use that to point to the Android SDK directory, by writing a line with the following form:
|
|
|
|
sdk.dir=PATH_TO_ANDROID_SDK
|
|
|
|
6. Run 'ant debug' in android/project. This compiles the .java and eventually
|
|
creates a .apk with the native code embedded
|
|
7. 'ant debug install' will push the apk to the device or emulator (if connected)
|
|
|
|
Here's an explanation of the files in the Android project, so you can customize them:
|
|
|
|
android-project/
|
|
AndroidManifest.xml - package manifest. Among others, it contains the class name
|
|
of the main Activity and the package name of the application.
|
|
build.properties - empty
|
|
build.xml - build description file, used by ant. The actual application name
|
|
is specified here.
|
|
default.properties - holds the target ABI for the application, android-10 and up
|
|
project.properties - holds the target ABI for the application, android-10 and up
|
|
local.properties - holds the SDK path, you should change this to the path to your SDK
|
|
jni/ - directory holding native code
|
|
jni/Android.mk - Android makefile that can call recursively the Android.mk files
|
|
in all subdirectories
|
|
jni/SDL/ - (symlink to) directory holding the SDL library files
|
|
jni/SDL/Android.mk - Android makefile for creating the SDL shared library
|
|
jni/src/ - directory holding your C/C++ source
|
|
jni/src/Android.mk - Android makefile that you should customize to include your
|
|
source code and any library references
|
|
res/ - directory holding resources for your application
|
|
res/drawable-* - directories holding icons for different phone hardware. Could be
|
|
one dir called "drawable".
|
|
res/layout/main.xml - Usually contains a file main.xml, which declares the screen layout.
|
|
We don't need it because we use the SDL video output.
|
|
res/values/strings.xml - strings used in your application, including the application name
|
|
shown on the phone.
|
|
src/org/libsdl/app/SDLActivity.java - the Java class handling the initialization and binding
|
|
to SDL. Be very careful changing this, as the SDL library relies
|
|
on this implementation.
|
|
|
|
|
|
================================================================================
|
|
Build an app with static linking of libSDL
|
|
================================================================================
|
|
|
|
This build uses the Android NDK module system.
|
|
|
|
Instructions:
|
|
1. Copy the android-project directory wherever you want to keep your projects
|
|
and rename it to the name of your project.
|
|
2. Rename <project>/jni/src/Android_static.mk to <project>/jni/src/Android.mk
|
|
(overwrite the existing one)
|
|
3. Edit <project>/jni/src/Android.mk to include your source files
|
|
4. create and export an environment variable named NDK_MODULE_PATH that points
|
|
to the parent directory of this SDL directory. e.g.:
|
|
|
|
export NDK_MODULE_PATH="$PWD"/..
|
|
|
|
5. Edit <project>/src/org/libsdl/app/SDLActivity.java and remove the call to
|
|
System.loadLibrary("SDL2").
|
|
6. Run 'ndk-build' (a script provided by the NDK). This compiles the C source
|
|
|
|
|
|
================================================================================
|
|
Customizing your application name
|
|
================================================================================
|
|
|
|
To customize your application name, edit AndroidManifest.xml and replace
|
|
"org.libsdl.app" with an identifier for your product package.
|
|
|
|
Then create a Java class extending SDLActivity and place it in a directory
|
|
under src matching your package, e.g.
|
|
|
|
src/com/gamemaker/game/MyGame.java
|
|
|
|
Here's an example of a minimal class file:
|
|
|
|
--- MyGame.java --------------------------
|
|
package com.gamemaker.game;
|
|
|
|
import org.libsdl.app.SDLActivity;
|
|
|
|
/**
|
|
* A sample wrapper class that just calls SDLActivity
|
|
*/
|
|
|
|
public class MyGame extends SDLActivity { }
|
|
|
|
------------------------------------------
|
|
|
|
Then replace "SDLActivity" in AndroidManifest.xml with the name of your
|
|
class, .e.g. "MyGame"
|
|
|
|
================================================================================
|
|
Customizing your application icon
|
|
================================================================================
|
|
|
|
Conceptually changing your icon is just replacing the "ic_launcher.png" files in
|
|
the drawable directories under the res directory. There are four directories for
|
|
different screen sizes. These can be replaced with one dir called "drawable",
|
|
containing an icon file "ic_launcher.png" with dimensions 48x48 or 72x72.
|
|
|
|
You may need to change the name of your icon in AndroidManifest.xml to match
|
|
this icon filename.
|
|
|
|
================================================================================
|
|
Loading assets
|
|
================================================================================
|
|
|
|
Any files you put in the "assets" directory of your android-project directory
|
|
will get bundled into the application package and you can load them using the
|
|
standard functions in SDL_rwops.h.
|
|
|
|
There are also a few Android specific functions that allow you to get other
|
|
useful paths for saving and loading data:
|
|
* SDL_AndroidGetInternalStoragePath()
|
|
* SDL_AndroidGetExternalStorageState()
|
|
* SDL_AndroidGetExternalStoragePath()
|
|
|
|
See SDL_system.h for more details on these functions.
|
|
|
|
The asset packaging system will, by default, compress certain file extensions.
|
|
SDL includes two asset file access mechanisms, the preferred one is the so
|
|
called "File Descriptor" method, which is faster and doesn't involve the Dalvik
|
|
GC, but given this method does not work on compressed assets, there is also the
|
|
"Input Stream" method, which is automatically used as a fall back by SDL. You
|
|
may want to keep this fact in mind when building your APK, specially when large
|
|
files are involved.
|
|
For more information on which extensions get compressed by default and how to
|
|
disable this behaviour, see for example:
|
|
|
|
http://ponystyle.com/blog/2010/03/26/dealing-with-asset-compression-in-android-apps/
|
|
|
|
================================================================================
|
|
Pause / Resume behaviour
|
|
================================================================================
|
|
|
|
If SDL is compiled with SDL_ANDROID_BLOCK_ON_PAUSE defined (the default),
|
|
the event loop will block itself when the app is paused (ie, when the user
|
|
returns to the main Android dashboard). Blocking is better in terms of battery
|
|
use, and it allows your app to spring back to life instantaneously after resume
|
|
(versus polling for a resume message).
|
|
|
|
Upon resume, SDL will attempt to restore the GL context automatically.
|
|
In modern devices (Android 3.0 and up) this will most likely succeed and your
|
|
app can continue to operate as it was.
|
|
|
|
However, there's a chance (on older hardware, or on systems under heavy load),
|
|
where the GL context can not be restored. In that case you have to listen for
|
|
a specific message, (which is not yet implemented!) and restore your textures
|
|
manually or quit the app (which is actually the kind of behaviour you'll see
|
|
under iOS, if the OS can not restore your GL context it will just kill your app)
|
|
|
|
================================================================================
|
|
Threads and the Java VM
|
|
================================================================================
|
|
|
|
For a quick tour on how Linux native threads interoperate with the Java VM, take
|
|
a look here: http://developer.android.com/guide/practices/jni.html
|
|
|
|
If you want to use threads in your SDL app, it's strongly recommended that you
|
|
do so by creating them using SDL functions. This way, the required attach/detach
|
|
handling is managed by SDL automagically. If you have threads created by other
|
|
means and they make calls to SDL functions, make sure that you call
|
|
Android_JNI_SetupThread() before doing anything else otherwise SDL will attach
|
|
your thread automatically anyway (when you make an SDL call), but it'll never
|
|
detach it.
|
|
|
|
================================================================================
|
|
Using STL
|
|
================================================================================
|
|
|
|
You can use STL in your project by creating an Application.mk file in the jni
|
|
folder and adding the following line:
|
|
|
|
APP_STL := stlport_static
|
|
|
|
For more information check out CPLUSPLUS-SUPPORT.html in the NDK documentation.
|
|
|
|
================================================================================
|
|
Additional documentation
|
|
================================================================================
|
|
|
|
The documentation in the NDK docs directory is very helpful in understanding the
|
|
build process and how to work with native code on the Android platform.
|
|
|
|
The best place to start is with docs/OVERVIEW.TXT
|
|
|
|
|
|
================================================================================
|
|
Using Eclipse
|
|
================================================================================
|
|
|
|
First make sure that you've installed Eclipse and the Android extensions as described here:
|
|
http://developer.android.com/tools/sdk/eclipse-adt.html
|
|
|
|
Once you've copied the SDL android project and customized it, you can create an Eclipse project from it:
|
|
* File -> New -> Other
|
|
* Select the Android -> Android Project wizard and click Next
|
|
* Enter the name you'd like your project to have
|
|
* Select "Create project from existing source" and browse for your project directory
|
|
* Make sure the Build Target is set to Android 3.1 (API 12)
|
|
* Click Finish
|
|
|
|
|
|
================================================================================
|
|
Using the emulator
|
|
================================================================================
|
|
|
|
There are some good tips and tricks for getting the most out of the
|
|
emulator here: http://developer.android.com/tools/devices/emulator.html
|
|
|
|
Especially useful is the info on setting up OpenGL ES 2.0 emulation.
|
|
|
|
Notice that this software emulator is incredibly slow and needs a lot of disk space.
|
|
Using a real device works better.
|
|
|
|
================================================================================
|
|
Troubleshooting
|
|
================================================================================
|
|
|
|
You can create and run an emulator from the Eclipse IDE:
|
|
* Window -> Android SDK and AVD Manager
|
|
|
|
You can see if adb can see any devices with the following command:
|
|
|
|
adb devices
|
|
|
|
You can see the output of log messages on the default device with:
|
|
|
|
adb logcat
|
|
|
|
You can push files to the device with:
|
|
|
|
adb push local_file remote_path_and_file
|
|
|
|
You can push files to the SD Card at /sdcard, for example:
|
|
|
|
adb push moose.dat /sdcard/moose.dat
|
|
|
|
You can see the files on the SD card with a shell command:
|
|
|
|
adb shell ls /sdcard/
|
|
|
|
You can start a command shell on the default device with:
|
|
|
|
adb shell
|
|
|
|
You can remove the library files of your project (and not the SDL lib files) with:
|
|
|
|
ndk-build clean
|
|
|
|
You can do a build with the following command:
|
|
|
|
ndk-build
|
|
|
|
You can see the complete command line that ndk-build is using by passing V=1 on the command line:
|
|
|
|
ndk-build V=1
|
|
|
|
If your application crashes in native code, you can use addr2line to convert the
|
|
addresses in the stack trace to lines in your code.
|
|
|
|
For example, if your crash looks like this:
|
|
|
|
I/DEBUG ( 31): signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 400085d0
|
|
I/DEBUG ( 31): r0 00000000 r1 00001000 r2 00000003 r3 400085d4
|
|
I/DEBUG ( 31): r4 400085d0 r5 40008000 r6 afd41504 r7 436c6a7c
|
|
I/DEBUG ( 31): r8 436c6b30 r9 435c6fb0 10 435c6f9c fp 4168d82c
|
|
I/DEBUG ( 31): ip 8346aff0 sp 436c6a60 lr afd1c8ff pc afd1c902 cpsr 60000030
|
|
I/DEBUG ( 31): #00 pc 0001c902 /system/lib/libc.so
|
|
I/DEBUG ( 31): #01 pc 0001ccf6 /system/lib/libc.so
|
|
I/DEBUG ( 31): #02 pc 000014bc /data/data/org.libsdl.app/lib/libmain.so
|
|
I/DEBUG ( 31): #03 pc 00001506 /data/data/org.libsdl.app/lib/libmain.so
|
|
|
|
You can see that there's a crash in the C library being called from the main code.
|
|
I run addr2line with the debug version of my code:
|
|
|
|
arm-eabi-addr2line -C -f -e obj/local/armeabi/libmain.so
|
|
|
|
and then paste in the number after "pc" in the call stack, from the line that I care about:
|
|
000014bc
|
|
|
|
I get output from addr2line showing that it's in the quit function, in testspriteminimal.c, on line 23.
|
|
|
|
You can add logging to your code to help show what's happening:
|
|
|
|
#include <android/log.h>
|
|
|
|
__android_log_print(ANDROID_LOG_INFO, "foo", "Something happened! x = %d", x);
|
|
|
|
If you need to build without optimization turned on, you can create a file called
|
|
"Application.mk" in the jni directory, with the following line in it:
|
|
|
|
APP_OPTIM := debug
|
|
|
|
|
|
================================================================================
|
|
Memory debugging
|
|
================================================================================
|
|
|
|
The best (and slowest) way to debug memory issues on Android is valgrind.
|
|
Valgrind has support for Android out of the box, just grab code using:
|
|
|
|
svn co svn://svn.valgrind.org/valgrind/trunk valgrind
|
|
|
|
... and follow the instructions in the file README.android to build it.
|
|
|
|
One thing I needed to do on Mac OS X was change the path to the toolchain,
|
|
and add ranlib to the environment variables:
|
|
export RANLIB=$NDKROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/darwin-x86/bin/arm-linux-androideabi-ranlib
|
|
|
|
Once valgrind is built, you can create a wrapper script to launch your
|
|
application with it, changing org.libsdl.app to your package identifier:
|
|
|
|
--- start_valgrind_app -------------------
|
|
#!/system/bin/sh
|
|
export TMPDIR=/data/data/org.libsdl.app
|
|
exec /data/local/Inst/bin/valgrind --log-file=/sdcard/valgrind.log --error-limit=no $*
|
|
------------------------------------------
|
|
|
|
Then push it to the device:
|
|
|
|
adb push start_valgrind_app /data/local
|
|
|
|
and make it executable:
|
|
|
|
adb shell chmod 755 /data/local/start_valgrind_app
|
|
|
|
and tell Android to use the script to launch your application:
|
|
|
|
adb shell setprop wrap.org.libsdl.app "logwrapper /data/local/start_valgrind_app"
|
|
|
|
If the setprop command says "could not set property", it's likely that
|
|
your package name is too long and you should make it shorter by changing
|
|
AndroidManifest.xml and the path to your class file in android-project/src
|
|
|
|
You can then launch your application normally and waaaaaaaiiittt for it.
|
|
You can monitor the startup process with the logcat command above, and
|
|
when it's done (or even while it's running) you can grab the valgrind
|
|
output file:
|
|
|
|
adb pull /sdcard/valgrind.log
|
|
|
|
When you're done instrumenting with valgrind, you can disable the wrapper:
|
|
|
|
adb shell setprop wrap.org.libsdl.app ""
|
|
|
|
================================================================================
|
|
Why is API level 10 the minimum required?
|
|
================================================================================
|
|
|
|
API level 10 is the minimum required level at runtime (that is, on the device)
|
|
because SDL requires some functionality for running not
|
|
available on older devices. Since the incorporation of joystick support into SDL,
|
|
the minimum SDK required to *build* SDL is version 12. Devices running API levels
|
|
10-11 are still supported, only with the joystick functionality disabled.
|
|
|
|
Support for native OpenGL ES and ES2 applications was introduced in the NDK for
|
|
API level 4 and 8. EGL was made a stable API in the NDK for API level 9, which
|
|
has since then been obsoleted, with the recommendation to developers to bump the
|
|
required API level to 10.
|
|
As of this writing, according to http://developer.android.com/about/dashboards/index.html
|
|
about 90% of the Android devices accessing Google Play support API level 10 or
|
|
higher (March 2013).
|
|
|
|
================================================================================
|
|
A note regarding the use of the "dirty rectangles" rendering technique
|
|
================================================================================
|
|
|
|
If your app uses a variation of the "dirty rectangles" rendering technique,
|
|
where you only update a portion of the screen on each frame, you may notice a
|
|
variety of visual glitches on Android, that are not present on other platforms.
|
|
This is caused by SDL's use of EGL as the support system to handle OpenGL ES/ES2
|
|
contexts, in particular the use of the eglSwapBuffers function. As stated in the
|
|
documentation for the function "The contents of ancillary buffers are always
|
|
undefined after calling eglSwapBuffers".
|
|
Setting the EGL_SWAP_BEHAVIOR attribute of the surface to EGL_BUFFER_PRESERVED
|
|
is not possible for SDL as it requires EGL 1.4, available only on the API level
|
|
17+, so the only workaround available on this platform is to redraw the entire
|
|
screen each frame.
|
|
|
|
Reference: http://www.khronos.org/registry/egl/specs/EGLTechNote0001.html
|
|
|
|
================================================================================
|
|
Known issues
|
|
================================================================================
|
|
|
|
- The number of buttons reported for each joystick is hardcoded to be 36, which
|
|
is the current maximum number of buttons Android can report.
|
|
|