update windows side logics

Windows/README.md

@@ -4,7 +4,23 @@ This folder contains code for the windows program, which will catch the signals
 
 ------
 
-### vJoy  
-The code relies on the vJoy driver, so [install it](http://vjoystick.sourceforge.net/site/index.php/download-a-install/download) before running this program.  
+### Program Logics  
 
-------
+3 main threads:  
+1. system tray icon thread  
+2. Bluetooth server thread  
+3. Wheel driver thread  
+
+#### System Tray Thread  
+This thread will create new thread for 2 UIs if needed, and will also manage when to exit the whole program  
+
+#### Bluetooth Thread  
+This thread will start the Bluetooth listener with unique UUID, try to accept a potential client.  
+If connected, check the received data to determine whether the connected client is going to send useful data.  
+Specifically, the input stream will contain `0x7FFFFFFF` as first 4 bytes to indicate a incoming data flow, `0x7FFFFFFF` show again to indicate the closing of the input stream.  
+For the input stream itself, every 16 bytes (4 int) is regarded as a pack. The started int is always `10086` and the rest 3 ints are real input data. Therefore, the code will check every 16 bytes to make sure the data is received in valid order.  
+
+#### Wheel Thread  
+This thread will aquire a vJoy device and check if the device is valid.  
+Then it will starts reading data from a global buffer, where data are previously stored by the bluetooth thread. The read and write on global buffer uses object lock to ensure data safety.  
+Then for each instruction, trigger the device driver to send emulated signals.