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Info on Multiplayer and Gnet?

BlitzMax Forums/BlitzMax Programming/Info on Multiplayer and Gnet?

Chroma(Posted 2005) [#1]
I'm looking for some good info on the TCP/UDP and GNet commands. I've looked in archives and didn't see anything.


deps(Posted 2005) [#2]
Well, here is my quick tutorial on Gnet: http://www.blitzbasic.com/Community/posts.php?topic=51171

for tcp/udp socket programming, you have this one: http://beej.us/guide/bgnet/
Explains a lot and is just great, imo.


Tibit(Posted 2005) [#3]
Or if you want to it simple:

TNet-Basic

Starting Tutorial for TNet


Chroma(Posted 2005) [#4]
Sorry I wasn't more specific.

Anyone have some info on how to use the "existing" commands in BMax to get me started using UDP?


Chroma(Posted 2005) [#5]
Here's something I started messing with. FYI I don't know exactly what method works. I know how it worked in Blitz3D and it seems to have changed slightly.

Can someone give me some pointers?

Strict

Graphics 640,480,0

Const backlog:Int = 10

' Create UDP Socket
Global iSocket:TSocket = CreateUDPSocket()
BindSocket(iSocket,0)


While Not KeyHit(KEY_ESCAPE)
Cls

If KeyHit(KEY_UP)
Local out:Int = WriteStream(iSocket)
WriteLine out,"hi"
EndIf


knock = SocketListen(iSocket,backlog)
If knock Then Print "hello";End

DrawText DottedIP(SocketLocalIP(iSocket)),5,5
DrawText SocketLocalPort(iSocket),5,25

Flip
Wend
End



Tibit(Posted 2005) [#6]
I don't use streams for UDP so I can't help you with that, if that is really what you want, but I guess you simply want to send data, in which this might be your solution. With UDP I send packages, the opposite with TCP, where I split the stream up into packages.

Here is the command for sending UDP with the core blitzmax commands (nothing to do with TNet, except this is what TNet uses):
sendto_( Socket._socket, Bytes:Byte Ptr, Byte_length, flags, Dest_IP, Dest_Port )

Socket: The socket you want to use, with UDP you can use one socket for ALL your messages on one port. _socket is the field in the Socket type that the sendto_ function wants.

Bytes: a Byte Ptr to the first byte of the data you want to send.

Byte_Length: The length of the data to send.

flags: If you don't know this, don't use it.

Dest_IP: The ip in int form of the receiver of your message

Dest_Port: The port on the receiving computer you want to send to.

You will save a lot of work if you use TNet, and in the next version you will be able to use blitz sockets combined with TNet. SocketDataSendTo( Socket:TSocket, Data$, Dest_IP, Dest_Port).


Chroma(Posted 2005) [#7]
I want to learn to do this myself but there's no examples of how to successfully use the sockets in the documentation.

I don't necessarily want to use Streams, I just want to use whatever works fast for a multiplayer game. I know for UDP it's connectionless and you just make a packet and shoot it to the IP/Port. I'm just trying to get that working in it's most basic form.

Where is the sendto_() command in the docs?

I try to use sendto_() and it says "Identifier Not Found".


Chroma(Posted 2005) [#8]
So my line would look like?
sendto_(iSocket:TSocket,0,5,0,"127.0.0.1",SocketLocalPort(iSocket))


But if the message I want to send is contained in SEND$ how do I actually send it?


deps(Posted 2005) [#9]
sendto_( iSocket, varptr SEND, len(SEND), 0, HostIP("127.0.0.1"), SocketLocalPort(iSocket) )


I think. Never used it myself.


Chroma(Posted 2005) [#10]
Tried that and is says:

Unable to Convert 'TSocket' to 'Int'

So it looks like the first spot can't be a TSocket?


Tom(Posted 2005) [#11]
http://www.blitzbasic.com/Community/posts.php?topic=50093

Don't think it's been added yet but still works fine here.


Chroma(Posted 2005) [#12]
Thanks for the help so far guys but I'm still stuck banging my head against the wall. :(

I try to put my socket in the first spot of sendto_() and it says it needs to be and Integer. :( :( :(


Hotcakes(Posted 2005) [#13]
Try going from SuperStrict to Strict. You can only explicitely convert object types in SuperStrict mode. Alternatively (and I'm only guessing here), you can do the explicit conversion by using Int(iSocket:TSocket).


Tibit(Posted 2005) [#14]
Socket._socket

Let us say your socket is like this:
Global iSocket:TSocket
iSocket = CreateSocket()
local Bytes[2]
Bytes[0] = 65 'Letter A
Bytes[1] = 66 'Letter B
sendto_( iSocket._socket,Bytes,Bytes.length,0,HostIp("127.0.0.1"), SocketWhichYouWantToSendToOnYourLocalComputer )
Should send "AB" to your own computer because you use 127.0.0.1 and then to whatever port you specify.


Chroma(Posted 2005) [#15]
Thanks for the info Wave.

Are you using Banks to convert strings to bytes?


Tibit(Posted 2005) [#16]
no

Also right now TNet only support 8bit Strings.


Tibit(Posted 2005) [#17]
I guess you want to receive to:

recvfrom_( Socket._socket, Bytes, BytesToReceive , flags, Sender_IP , Sender_Port )


Chroma(Posted 2005) [#18]
How does this look for preparing a packet for transmittal?

chat:Packet = Packet.Create("Can you hear me Dr. Watson?")

Print chat.UnPack()

Type Packet 

	Field bytes[]
	Field size:Int

	Function Create:Packet(msg:String)
		Local p:Packet = New Packet
		p.size = Len(msg)
		p.bytes = New Int[p.size]
		For Local i = 0 To p.size-1
			p.bytes[i] = Asc( Mid$( msg,i+1,1 ) )
		Next
		Return p
	End Function

	Method UnPack:String()
		Local msg:String
		For Local i:Int = 0 To size-1
			msg = msg + Chr$( bytes[i] ) 
		Next
		Return msg
	End Method
	
	Method Send()
		'sendto_(iSocket._socket,p.bytes,p.size,0,p.IP,p.Port)
	End Method

End Type



Tibit(Posted 2005) [#19]
This is how I would have "packed" the package to bytes.


Also when you do the Asci/byte math:
For Local i = 0 To p.size-1
p.bytes[i] = Asc( Mid$( msg,i+1,1 ) )
Next
This is the new BlitzMax Way. Nicer and easier to read once you get used to it.
For Local i = 0 To p.size-1
p.bytes[i] = msg[i]
Next

Also I also think you can use Until instead:
For Local i = 0 until p.size
p.bytes[i] = msg[i]
Next