netplay.txt

how to netplay in unofficial nester
-----------------------------------


*****              OUT OF SUPPORT,               *****
***** DONT ASK ME QUESTION ABOUT NETWORK FEATURE *****


how to use netplay feature:

server:
  * load ROM
  * select "File"-"netplay"-"server (1P)"
  * input Network Latency ( 0(auto), 1(fast) - 9(slow))
    and Port number (1024-65535 except 8080, default:10000)

  then server starts waiting client connection.

  * if you wanna exit waiting client's connection,
    select "File"-"netplay"-"cancel connection"

client: (after server setup)

  * load same ROM
  * select "File"-"netplay"-"client (2P)"
  * input Server's IP Address (XXX.XXX.XXX.XXX) and Port number.


when connected, both server and client reset and start games.
server controls 1P, and client controls 2P.
but you must use 1P's pad of client machine to control 2P.
(because almost user seem to have only 1 pad. I too.)

while netplay, close button on the window title bar is grayed.
its enabled again when disconnected.
select "File"-"netplay"-"disconnect" to exit netplay.

when emulation is paused (beause of kill forcus, touch menu bar, ...),
connection between server and client must be broken.
if control seems to be freezed, please disconnect.

both server and client, usualy send only pad infomation,
so not supported games that use external devices.

  exception: MIC, VS-Unisystem's InsertCoin, HyperShot
             (nester sends these info as pad bits)

support FDS, but only server can change disk side.
and use shortcut key 'A' - 'E' to change it.(dont use menu)

save data must be same if exist.
if FDS, disk image (include written data) must be same.

GameGenie code is supported in netplay, but both must have same code.
Movie feature is not supported in netplay.


note:
support both LAN and Internet.

note2:
dont use CTRL+ALD+DEL to shutdown nester while netplay.
windows destroys only window, ghost task remains.
use "File"-"Netplay"-"disconnect" to exit netplay.

note3:
of course, need TCP/IP. :-)


-------------------------------------------------------------------------------

protocol (rev.2)
----------------

(connection)

     SERVER                   CLIENT
    --------                 --------
    accepting client                                   
                             connect to server         

    send sv_version          send cl_version           = 0x02
    recv cl_version          recv sv_version           
    compare versions         compare versions          if not same, exit

    dwFirst = timeGetTime                              check network latency
    send 0x00                                          
                             recv                      
                             send 0x00                 
    recv                                               
    send 0x00                                          
                             recv                      
                             send 0x00                 
    recv                                               
    send 0x00                                          
                             recv                      
                             send 0x00                 
    recv                                               
    send 0x00                                          
                             recv                      
                             send 0x00                 
    recv                                               
    dwLast = timeGetTime                               

    latency = (uint8)((dwLast-dwFirst)*60/8000)+1      if latency auto setting
                                                       if latency > 30, exit
    send latency                                       
                             recv latency              

    send 0x00                send 0x00                 initial pad bits (dummy)


(sending pad info)

  top of ( m - latency)th frame
  -----------------------------
              :                        :               
              :                        :               
    past_pad1 = curr.pad1    past_pad1 = curr.pad1     
    past_pad2 = curr.pad2    past_pad2 = curr.pad2     
                             past_pad2 = past_pad1     
    (send ex_info)           (send ex_info)            
    send past_pad1           send past_pad2            

  top of ( m )th frame
  --------------------
    (ex_info = recv())       (ex_info = recv())        
    pad1 = past_pad1         pad1 = recv()             while (m)th -
    pad2 = recv()            pad2 = past_pad2            (m+latency-1)th,
                                                       return pad bits got at
    past_pad1 = curr.pad1    past_pad1 = curr.pad1       top of (m-latency)th
    past_pad2 = curr.pad2    past_pad2 = curr.pad2       frame.
                             past_pad2 = past_pad1     
    send past_pad1           send past_pad2            

  top of ( m + latency)th frame
  -----------------------------
    (ex_info = recv())       (ex_info = recv())        
    pad1 = past_pad1         pad1 = recv()             while (m+latency)th -
    pad2 = recv()            pad2 = past_pad2            (m+2*latency-1)th,
         :                        :                    return pad bits got at
         :                        :                      top of (m)th frame.

  * if MIC or InsertCoin is active, pad bits = 0x30.

  * if (recv() & 0xC0) == 0xC0, its data is ex_info and recv() again.

  * ex_info format
      11nndddd :  nn=type, dddd=data
      ---------------------------------------------
      1100---- : reserved
      1101---- : reserved
      1110---- : reserved
      1111-ddd : change disk side (ddd = disk side)

    (note: pad bits is RLDUbbbb, but never push R&L/D&U at the same time)

  * drop frame doesnt occur if data server(client) sent is recieved
    by client(server) in (time of 1 frame)*(latency).
    (note: the time of 1 frame is 1/60 sec.)


------------------------
TAKEDA, toshiya
t-takeda@m1.interq.or.jp