Add high level description of how JNI is used

README.md

@@ -9,7 +9,6 @@ The touch screen acts as a big trackpad for the mouse.  To click and drag,
 for example to pull down GS/OS menus, you need to Long Press first.
 
 What's not ready yet:
-- No audio.
 - No joystick.
 - Screen scaling to fit your device.
 - Native UI configuration options.
@@ -23,3 +22,26 @@ To build from source:
   (cd jni && ndk-build)
   ant debug install
 </pre>
+
+
+Changes made to KEGS:
+- Various ifdefs for __ANDROID__ in the kegs 'core'
+- Addition of android_driver.c and android_sound_driver.c
+
+Application structure:
+- The UI is coordinated via KegsMain
+- There is a KegsView$KegsThread class that gets its own thread.  This thread ends up calling mainLoop() in jni/android_driver.c and running KEGS in that thread.
+- The native thread gets two things from Java:
+-- a Bitmap
+-- a ConcurrentLinkedQueue
+
+All UI events are sent to the native thread by pushing events into the ConcurrentLinkedQueue (KegsEvent, MouseKegsEvent, KeyKegsEvent).
+
+The native thread pulls events off the queue, writes updates into the bitmap object, then calls the Java "updateScreen" in the KegsView$KegsThread object.
+
+The native thread also calls support functions in Java, such as checkForPause(), which deadlocks the thread while it should be paused.
+
+Android NDK samples were used as a base for this:
+- bitmap-plasma
+- JetBoy
+- native-audio