216 lines
13 KiB
Plaintext
216 lines
13 KiB
Plaintext
This is libSDL 1.2 and 1.3 ported to Google Android (also bunch of other libs included).
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Alien Blaster game is used as working example (original sources: http://www.schwardtnet.de/alienblaster/ ).
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Installation
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============
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This should be compiled with Android 2.2 SDK and NDK r4b - google for them and install them as described in their docs
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(the application will run on Android 1.6 and above).
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You'll need to install Ant too.
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The most supported environnment for that port is Linux, MacOs should be okay too,
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however if you'll use launchConfigure.sh script you'll have to replace "linux-x86" to "darwin-x86" inside it.
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If you're developing on Windows you'd better install andLinux or Ubuntu+Wubi, to get proper Linux environment
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running inside Windows, then install Linux toolchain on it. I was told andLinux compiles faster than Cygwin.
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Also you'll need full set of Linux utils and symlinks support to launch ChangeAppSettings.sh (sh, grep, sed, tr).
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How to compile Alien Blaster demo application
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=============================================
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Go to "project" directory and launch command
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android update project -p .
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Then go back, edit file build.sh if needed to add NDK dir to your PATH, then launch it.
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Hopefully it will compile a bunch of libs under project/libs/armeabi,
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create file project/bin/DemoActivity-debug.apk and install it on your device or emulator.
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Then you can test it by launching Alien Blaster icon from Android applications menu.
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It's designed for 640x480, so if you have smaller screen it will be resized.
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Note: The game enforces horizontal screen orientation, you may open your keyboard and use it for
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additional keys - the phone will just keep current screen orientation.
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Note that you may use Volume up/down and Camera keys as game inputs -
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you'll have to redefine them in game keyconfig menu.
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Keys Home, Search and End Call will force application quit, and because
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of a bug in my SDL implementation application will crash.
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Back key is mapped to Escape, and Menu is mapped to Enter.
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Newer Android phones like HTC Evo have no keyboard at all, so there are just 3 usable keys -
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Menu, Volume Up and Volume Down (and Escape of course).
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Because of that the accelerometer is configured to trigger cursor key events.
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This port also supports GL ES + SDL combo - there is GLXGears demo app in project/jni/application/glxgears,
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remove project/jni/application/src symlink and make new one pointing to glxgears,
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also you'll have to enable Z-Buffer in ChangeAppSettings.sh.
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Note that GL ES is NOT pure OpenGL - there are no glBegin() and glEnd() call and other widely used functions,
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and generally it will take a lot of effort to port pure OpenGL application to GL ES.
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How to compile your own application
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===================================
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When porting you own app, first of all ensure that your application supports
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native RGB_565 pixel format and AUDIO_S8 or AUDIO_S16 audio format
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(there is RGB_565 pixelformat even for OpenGL, not BGR_565 as all other OpenGL implementation have).
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Colorkey images are supported using RGBA_5551 pixelformat with 1-bit alpha (SDL does conversion internally,
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for you they are just RGB_565 surfaces), alpha surfaces have RGBA_4444 format.
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See file project/jni/application/alienblaster/SdlForwardCompat.h
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to learn how to make your application use SDL 1.3 instead of SDL 1.2 without much pain.
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HTC G1/Nexus One has native screen resolution 480x320, HTC Evo has 800x480, you may toggle automatic
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screen resizing in ChangeAppSettings.sh and draw to virtual 640x480 screen -
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it will be HW accelerated and will not impact performance much.
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SDL_ListModes()[0] will always return native screen resolution.
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Also make sure that your HW textures are not wider than 1024 pixels, or it will fail to allocate such
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texture on HTC G1. Software surfaces may be of any size of course (but you don't want to do expensive memcpy).
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Alternatively, SDL 1.2 is available too, you may use it with SW video as usual, however if you want HW acceleration
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there are few restrictions: you cannot currently blit SW surface to screen, it should be only HW surface,
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also alpha-surfaces seem to not work (did not check it thoroughly) - you still can use per-surface alpha.
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Basically your code should be like:
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// Init HW-accelerated video
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SDL_SetVideoMode( 640, 480, 16, SDL_DOUBLEBUF | SDL_HWSURFACE );
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// Load graphics
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SDL_Surface *sprite = IMG_Load( "sprite.png" );
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// Set pink color as transparent
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SDL_SetColorKey( sprite, SDL_SRCCOLORKEY, SDL_MapRGB(sprite->format, 255, 0, 255) );
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// Create HW-accelerated surface
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SDL_Surface * hwSprite = SDL_DisplayFormat(sprite);
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// Set per-surface alpha, if necessary
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SDL_SetAlpha( hwSprite, SDL_SRCALPHA, 128 );
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// Blit it in HW-accelerated way
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SDL_BlitSurface(hwSprite, sourceRect, SDL_GetVideoSurface(), &targetRect);
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// Wrong, blitting SW surfaces to screen not supported
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SDL_BlitSurface(sprite, sourceRect, SDL_GetVideoSurface(), &targetRect);
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// Wrong, copying from video surface not supported
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SDL_BlitSurface(SDL_GetVideoSurface(), sourceRect, sprite, &targetRect);
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To compile your own app, put your app sources into project/jni/application dir, and change symlink "src"
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to point to your app, then launch script ChangeAppSettings.sh - it will ask few questions and modify some Java code.
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The C++ files shall have .cpp extension to be compiled, rename them if necessary.
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Also you can replace icon image at project/res/drawable/icon.png.
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Then you can launch build.sh.
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The NDK has RTTI and exceptions disabled for C++ code, if you need them you may download modified NDK from
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http://www.crystax.net/android/ndk-r4.php
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Unzip it, and put in your PATH instead of original NDK - do not rename the target dir, my makefiles will
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check if there's "crystax" string in path to gcc toolchain, and will disable STLPort because CrystaX's
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NDK already contains STL library.
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Application data is not bundled with app itself - it should be downloaded from net on first run.
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Create .ZIP file with your application data, and put it somewhere on HTTP server - ChangeAppSettings.sh
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will ask you for the URL.
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If you'll release new version of data files you should change download URL and update your app as well -
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the app will re-download the data if URL does not match the saved URL from previous download.
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If you'll add new libs - add them to project/jni/, copy Android.mk from existing lib, and
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add libname to project/jni/<yourapp>/Android.mk
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How to compile your own application using automake/configure scripts
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====================================================================
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There is limited support for "configure" scripts, I've managed to compile lbreakout2 that way,
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though ./configure scripts tend to have stupid bugs in various places, avoid using that method if you can.
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1. Download lbreakout2-2.6.1.tar.gz from http://lgames.sourceforge.net/, unpack it to project/jni/application dir.
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2. Determine libraries needed for your app, launch ChangeAppSettings.sh, select correct libSDL version
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(1.2 for lbreakout2), and correct libs (sdl_mixer sdl_image sdl_net for lbreakout2), also change name etc.
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3. Launch ./build.sh, wait till it builds all .so files
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4. Go to project/jni/application/lbreakout2-2.6.1 dir, and launch command
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../launchConfigure.sh --disable-install --enable-sdl-net LIBS=-lintl
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5. Watch how ./configure configures, if it fails fix launchConfigure.sh, rinse and repeat.
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6. Launch make, and pray. If you're lucky it will create application binary (lbreakout2-2.6.1/client/lbreakout2)
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7. Move the application binary to dir project/libs/armeabi, rename it to libapplication.so (overwrite old file)
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8. Run command "arm-eabi-strip --strip-debug libapplication.so", you can find arm-eabi-strip under your NDK dir.
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9. Run "ant debug" or "ant release" from project dir, install to device & enjoy.
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Quick guide to debug native code
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================================
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To debug your application add tag 'android:debuggable="true"' to 'application' element in AndroidManifest.xml,
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recmpile and reinstall your app to Android 2.2 emulator or Android 2.2 device, go to "project" dir and launch command
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ndk-gdb --verbose --start --force
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then when it fails enter command
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target remote:5039 (then it will fail again)
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Note that it's extremely buggy, and I had no any success in debugging my app with ndk-gdb.
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So it's best to debug with code like:
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__android_log_print(ANDROID_LOG_INFO, "My App", "We somehow reached execution point #224");
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and then watching "adb logcat" output.
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If your application crashed, you should use following steps:
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1. Gather the crash report from "adb logcat" - it should contain stack trace, if it does not then you're unlucky,
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I/DEBUG ( 51): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
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I/DEBUG ( 51): Build fingerprint: 'sprint/htc_supersonic/supersonic/supersonic:2.1-update1/ERE27/194487:userdebug/test-keys'
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I/DEBUG ( 51): pid: 915, tid: 924 >>> de.schwardtnet.alienblaster <<<
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I/DEBUG ( 51): signal 11 (SIGSEGV), fault addr deadbaad
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I/DEBUG ( 51): r0 00000000 r1 afe133f1 r2 00000027 r3 00000058
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I/DEBUG ( 51): r4 afe3ae08 r5 00000000 r6 00000000 r7 70477020
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I/DEBUG ( 51): r8 000000b0 r9 ffffff20 10 48552868 fp 00000234
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I/DEBUG ( 51): ip 00002ee4 sp 485527f8 lr deadbaad pc afe10aac cpsr 60000030
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I/DEBUG ( 51): #00 pc 00010aac /system/lib/libc.so
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I/DEBUG ( 51): #01 pc 0000c00e /system/lib/libc.so
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I/DEBUG ( 51): #02 pc 0000c0a4 /system/lib/libc.so
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I/DEBUG ( 51): #03 pc 0002ca00 /data/data/de.schwardtnet.alienblaster/lib/libsdl.so
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I/DEBUG ( 51): #04 pc 00028b6e /data/data/de.schwardtnet.alienblaster/lib/libsdl.so
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I/DEBUG ( 51): #05 pc 0002d080 /data/data/de.schwardtnet.alienblaster/lib/libsdl.so
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2. Go to project/bin/ndk/local/armeabi dir, find there the library mentioned in stacktrace
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(libsdl.so in our example), copy the address of the first line of stacktrace (0002ca00), and execute command
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gdb libsdl.so -ex "list *0x0002ca00"
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It will output the exact line in your source where the application crashed.
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Known bugs
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==========
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0. Application will crash when you're pressing "Home" button or open/close keyboard
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- the correct behavior for Android apps is to stay in memory and go to foreground
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when you're launching app again, that's not working yet because
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app will lose OpenGL context (there are rumors that it won't lose GL context in 2.1 SDK).
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Anyway, SDL should sleep inside SDL_Flip() and re-create all HW textures when it gains back video.
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1. Merge all config screens into single big config screen, make option to rerun config.
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2. Fix on-screen keyboard, add more keys and more options, make possible for application to control it.
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3. Add full QWERTY on-screen keyboard.
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4. Add trackball sensitivity and accelerometer sensitivity config.
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5. Export phone vibrator to SDL - interface is available in SDL 1.3
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6. HDMI output (HTC Evo and Samsung Epic support that):
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HDMI output will be tricky - I've read the doc here:
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https://docs.google.com/View?id=dhtsnvs6_57d2hpqtgr#4_1_HDMI_output_support_338048
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It says that in order to output something to HDMI you need to have a VideoView class visible on screen:
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http://developer.android.com/reference/android/widget/VideoView.html .
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This class does not have any method like "showMyOwnCustomImage()",
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it just plays the video from the given path, so obvious solution is to create
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special FIFO file or open a socket, point the VideoView to play this FIFO or socket,
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and then write raw uncompressed video frames to that FIFO with some small header so that
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VideoView will recognize it as a proper video format.
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UQM gives 5 FPS without such hacks, if I'll implement that FPS will drop to 1-2
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(maybe not that bad, I have to actually try that), because you'll have to do huge memcpy(),
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plus VideoView will contain some buffer to ensure the playback is smooth,
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so the data on your TV will lag halfsecond behind the data on the device screen.
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7. Make app data to come inside .apk file in assets instead of downloading it from net.
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Games to port
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=============
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TeeWorlds
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SuperTux
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LBreakout2
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Commander Genius (only data files for shareware version available for free)
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OpenJazz (only data files for shareware version available for free)
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OpenLieroX (will be damn hard to do, I wrote the code partially)
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ScummVM (they already have their own port, yet it's unfinished)
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Widelands (http://wl.widelands.org/)
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License information
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===================
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The libSDL port itself is licensed under LGPL.
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It contains separate libraries under project/jni, each of which has it's own license,
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I've tried to compile all LGPL-ed libs as shared libs but you should anyway inspect the licenses
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of the libraries you're linking to if you're creating closed-source app.
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The "Ultimate Droid" button theme by Sean Stieber is licensed under Creative Commons - Attribution license.
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