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<DIV><FONT size=2 face=Arial>Hi there,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Yes, I should be able to easily enough. All that'll
happen is you'll hear the footstep at once, and then you'd be silently pushed
back to your original location if the server refuses your move. Could be a bit
of a confusing situation though, since we have to wait at least one roundtrip to
get the result of our move. And should these things be sent
reliably?</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Kind regards,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Philip Bennefall</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=jsprenkle@gmail.com href="mailto:jsprenkle@gmail.com">Jay
Sprenkle</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=philip@blastbay.com
href="mailto:philip@blastbay.com">philip@blastbay.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, November 24, 2010 1:48
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [ENet-discuss] Best
practises for synchronizing states</DIV>
<DIV><BR></DIV><BR>To combat lag in some games they send a packet indicating a
player will move, then while waiting for the server to validate the movement
predict the new player position, and render it to show the user. If the server
doesn't get the update or refuses it then the local position is corrected. You
might have seen the 'rubber banding' effect.<BR><BR>Can you do something
similar with sound? <BR><BR><BR>
<DIV class=gmail_quote>On Tue, Nov 23, 2010 at 9:00 PM, Philip Bennefall <SPAN
dir=ltr><<A
href="mailto:philip@blastbay.com">philip@blastbay.com</A>></SPAN>
wrote:<BR>
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class=gmail_quote>
<DIV bgcolor="#ffffff">
<DIV><FONT size=2 face=Arial>Hi all,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>This is a fairly lengthy email, so I apologize
in advance.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I am relatively new to ENet. I have integrated
it in my game engine and have successfully written a game which is working
perfectly. It is one of those finger twitching action games where speed is
of the utmost importance and delay is the most evil thing in the world. The
way I do it is to keep sending the entire state for a player to the other
party unreliably. The other client then works out the events that "must"
have occured by looking at the differences between the last known state and
the new one. This is far from a perfect solution as it neither scales well
nor provides for very readable code. Here's a summary of how I'm handling
things:</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>The game is a shooter where you run a round on
a 1d grid firing rocks at your oponent's palace. When a rock hits a square
on the other side it'll quickly begin piercing its way through until
that section of the wall crumbles. During that time, the other player may
use their hammer to defend the section.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I wrote an internal layout description for
myself before I started coding, which I then followed to ensure proper
handling of all possible situations.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>---Start of Internal
Description---</FONT></DIV>
<DIV><FONT size=2 face=Arial>The way in which this game communicates over
the network is fairly simple. The two players have a direct connection
established between one another, and they send out their player state
roughly 30 times a second. This player state contains the current x
position, the current throwing position which is -1 if nothing is being
thrown, and then a list of all the squares on that player's side. For each
square, two values are stored. The first is the current resistance which is
20 on max, and 0 if the square is destroyed. The second one is crumbling
speed which is 0 if the square is not currently crumbling, and a value in
milliseconds otherwise. This value is used to measure if two or more rocks
have been thrown on the same square.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>When a new state is received from the remote
player, we have to analyse this information in order to determine what
changes that have occured and if we need to take any action.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>If a new x position is received, we simply move
the player's local variable to this square and play a footstep
sound.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>If the new throwing position is different from
our old one, we can take a few actions depending on its value:</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>1. If the new one is greater than -1 and the
old one is -1, the remote player threw a rock at us. we play the throwing
sound in the appropriate location, but take no other action.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>2. If the new one is -1 and the old one is
greater than -1, we can assume that the remote player hit us and start the
crumbling sequence for that square on our end. Naturally if our square is
already crumbled, the remote player will not get any hit notifications from
us. </FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>3. If they both are greater than -1, we can
assume that the remote player hit us and so we activate that sequence as
above. We can also assume that the remote player made a new throwing attempt
in another location and that we didn't see the -1 state that came prior to
it probably because of lag, and so we play another throwing sound in the new
location.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>After this, we go on to scan the game board and
do the following for each square:</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>If the new resistance is greater than the old
one, the remote player hammered and so we play that sound.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>If the new resistance is lower than the old
one, we can take four actions.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV><FONT size=2 face=Arial>
<DIV><BR>1. If the new resistance is 0 and the old resistance is greater
than 0, the square just broke so we play the appropriate sound and forget
about it.</DIV>
<DIV> </DIV>
<DIV>2. If the old crumbling speed is the same as the new one, this was a
normal crumbling step and so we play the appropriate sound.</DIV>
<DIV> </DIV>
<DIV>3. If the old crumbling speed is 0 and the new one is greater than 0,
this was a new hit so we react accordingly.</DIV>
<DIV> </DIV>
<DIV>4. If the old one is greater than the new one and the new one is
greater than 0, this was a new hit on the same square.<BR></DIV></FONT><FONT
size=2 face=Arial>---End of Internal Description---</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I realize that this is a lot of very game
specific information, and that's exactly my point. This all seems like a
very dirty hack to me, and I was wondering if any of you can suggest a
better and more scalable way of doing this while still keeping latency to an
absolute minimum?</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Thanks in advance for any help!</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Kind regards,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV><FONT color=#888888>
<DIV><FONT size=2 face=Arial>Philip Bennefall</FONT></DIV></FONT>
<DIV><FONT size=2 face=Arial>P.S. I should perhaps mention that this is a
game for the blind; entirely based on sound, which is why sounds are
mentioned all over the place rather than
graphics.</FONT></DIV><BR>_______________________________________________<BR>ENet-discuss
mailing list<BR><A
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target=_blank>http://lists.cubik.org/mailman/listinfo/enet-discuss</A><BR><BR></BLOCKQUOTE></DIV><BR><BR
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