[sldev] Gesture client code Re: Anyone here with OpenCV experience?

[Melinda Green]

I don't agree that the amount of time required to implement this is 
terribly important since the amount of time required to maintain any 
feature over it's lifetime is roughly an order of magnitude greater. We 
might have spent quite a bit of calendar time so far but I don't think 
that anybody has made a big personal time investment yet. If that's not 
true, I hope that they'll tell us because you did ask for volunteers to 
write viewer-side patches for this. Otherwise I feel pretty good that 
this discussion has taken place.

-Melinda

Philip Rosedale wrote:
> Hmmm.  We're spending more time on this in conversation than the time 
> required to write the code, I fear. Bummer. 
>
> Well, practically speaking, we've got an intern starting who is going 
> to write some code to try to do this thing.  If our team does this, we 
> will do it as best we can and get some code submitted.  We've read 
> this thread, so thanks.  I think our direction will be to use UDP.  We 
> will do what we can and show everyone when we have working code.
>
> P
>
>
>
> John Hurliman wrote:
>> UDP is a poor choice for creating pipes between applications. I don't 
>> know how OSX behaves, but the networking stack in the flavors of 
>> Linux I'm familiar with and all versions of Windows are designed to 
>> drop UDP packets; even on the loopback connection. When you hit a 
>> certain frequency of message delivery (which is easy to do on 
>> loopback) you will start consistently dropping some percentage of the 
>> data. Even if you design your protocol around accepting random data 
>> loss, the deterministic way that packets are dropped will almost 
>> always lead to unacceptable results.
>>
>> As a side note, there is a growing body of evidence that suggests TCP 
>> will outperform UDP even in cases where UDP would be the logical 
>> choice. Decades of testing and tuning, careful synchronization of 
>> implementations (see RFC 1122 and 2988 for example), hardware 
>> acceleration of the TCP/IP stack, and a prioritization of TCP over 
>> UDP in today's routing hardware gives it a seriously unfair 
>> advantage. This isn't really related to the choice of protocol for 
>> creating a local pipe though.
>>
>> John
>>
>> On Fri, May 22, 2009 at 4:23 PM, Philip Rosedale 
>> <philip at lindenlab.com <mailto:philip at lindenlab.com>> wrote:
>>
>>     Looks like DBus is TCP based - that still seems unneeded, I think we
>>     should use UDP,  what think?
>>
>>     Jan Ciger wrote:
>>     > XML is definitely an overkill and certainly shouldn't be used for
>>     > anything that has aspirations to be lightweight.
>>     >
>>     > Just use DBus - that is pretty standard and portable
>>     lightweight RPC
>>     > mechanism and it is in the viewer already - it is used for passing
>>     > slurls to the viewer from Linux browser.
>>     >
>>     > That would also allow easy scripting of the viewer in the future.
>>     >
>>     > Regards,
>>     >
>>     > Jan
>>     >
>>     _______________________________________________
>>     Policies and (un)subscribe information available here:
>>     http://wiki.secondlife.com/wiki/SLDev
>>     Please read the policies before posting to keep unmoderated
>>     posting privileges
>>
>>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Policies and (un)subscribe information available here:
> http://wiki.secondlife.com/wiki/SLDev
> Please read the policies before posting to keep unmoderated posting privileges