stk-code_catmod/android/README.ANDROID

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 SUPERTUXKART

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--------------------------------------------------------------------------------
 SYSTEM REQUIREMENTS
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To run SuperTuxKart on Android, you need a device that meets following
requirements:

- Android 4.4 or later
- Processor compatible with armv7 or x86
- GPU that supports OpenGL ES 3.0
- 1 GB RAM (STK uses ~150 MB in minimal configuration)
- 300 MB of free space on internal storage
- Touch screen or external keyboard



--------------------------------------------------------------------------------
 COMPILATION
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The build scripts are designed to run under linux. They may work under cygwin
after some tweaks, but atm. only linux is supported.

Dependencies list (may be incomplete):

    autoconf, automake, make, python, ant, imagemagick, cmake, vorbis-tools

Additionally some dependencies for optimize_data script:

    advancecomp, libjpeg-progs, optipng

Before compilation you must download the package with dependencies from:
https://github.com/supertuxkart/dependencies
and extract it to stk-code/lib. It contains sources of libraries that are used
in STK, but are not availiable in stk-code repository (curl, freetype, openal).

You need also Android SDK for android-19 platform (the API for Android 4.4) and
Android NDK (versions r12b and r13b have been tested).

You need to create proper "android-sdk" and "android-ndk" symlinks in the
directory with Android project, so that the compilation script will have access
to the SDK and NDK.

These paths can be also set in SDK_PATH and NDK_PATH environmental variables.

Before running the compilation, run the generate_assets script, so that
selected assets will be copied to "assets" directory, and then included in the
apk file.

You can select different karts and tracks by setting KARTS and TRACKS variables
in the generate_assets.sh script at the beginning of file.

When you are creating the assets directory manually, note that the
directories.txt file is urgently needed and it is used by the application for
extracting assets.

If the assets directory is already prepared, you can run "./make.sh" command to
build the project and create an apk file. Note that all arguments are passed to
the make command, so that you can run "./make.sh -j5" for multi-threaded build.

If you want to prepare a package for particular architecture, you can choose it
by setting the COMPILE_ARCH environmental variable. At this stage, supported
architectures are "armv7", "x86" and "aarch64". The default is "armv7".

Basically if all dependencies are installed in the system, it should be enough
to just run:

    export SDK_PATH=/path/to/your/android/sdk
    export NDK_PATH=/path/to/your/android/ndk
    ./generate_assets.sh
    ./make.sh -j5



--------------------------------------------------------------------------------
 KNOWN ISSUES
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1.  At this stage only shader-based (OpenGL ES 3.0) pipeline works. The fixed
    pipeline (GLES 2.0) could work (it works under linux), but it doesn't look
    good and is generally broken. It means that it's not possible to run STK on
    Android 4.2 or older. It is technically possible to do - check GLES context
    version, load OpenGL functions dynamically using EGL, and if they are not
    loaded properly, then fallback to GLES 2.0. But these devices may be too
    slow to run STK anyway.

2.  It never ocurred for me, but it's possible that EGL context is lost in some
    cases. SuperTuxKart is not designed to re-create all textures at any moment,
    so this is a "Wontfix", at least for now.

3.  Some bright tracks (Farm, Gran Paradiso) seem to be a bit darker in GLES
    renderer than in original OpenGL 3.x renderer. It can be easily hacked by
    adding few lines to object pass shader, but we should rather try to find the
    real reason.

4.  We use "exit(0)" at the end of main function. We shouldn't do it and we
    should just return from the main function. But STK uses some global
    variables and their values are remembered when the game is restarted. We
    should properly clear them or re-initialize on startup. Using the "exit(0)"
    is not-that-bad workaround, but it may cause a crash on exit sometimes.
    It seems to affect only Android 5.0. More information about the crash:
    https://code.google.com/p/android/issues/detail?id=160824

5.  STK crashes on Qualcomm with Adreno 305 when trying to draw menu interface.
    Backtrace shows glDrawElements function, and internally crashed in vbo
    allocation.

6.  STK crashes on startup on some devices when aarch64 build is made using
    Android r13 NDK. The r13 version has rather big modifications (it uses clang
    instead of gcc by default). This is probably a bug in NDK/compiler/OS, but
    for this reason using NDK r12 for 64-bit arm compilation is preferred.

7.  Angelscript doesn't have full support for aarch64 builds, so that scripting
    won't work on this platform.
    
8.  Turning left/right using accelerometer is available, but at this stage the
    default screen orientation is not automatically detected and user must 
    manually choose if he needs "phone" or "tablet" accelerometer.