[sldev] Client FPS & LLQuaternions

[Tofu Linden]

This is simply a guess, but if we're enforcing unit quaternions then a
4th coefficient can be inferred from the other three - so
sending just three over the wire is an optimization.

Thomas Grimshaw wrote:
> I've undone the zerocoding, and the official client only sends three F32 
> values per llQuaternion in
> the AgentUpdate packet. I've also written my own dummy client, and 
> confirmed that 16 byte
> values are not accepted by the sim in this particular message.
> 
> Cheers
> 
> Tom
> 
> ----- Original Message ----- From: "Kent Quirk (Q Linden)" 
> <q at lindenlab.com>
> To: "Thomas Grimshaw" <tom at streamsense.net>
> Cc: "Second Life Developer Mailing List" <sldev at lists.secondlife.com>
> Sent: Monday, February 18, 2008 5:18 AM
> Subject: Re: [sldev] Client FPS & LLQuaternions
> 
> 
>> A quaternion can be used as a way of expressing a 3D rotation. Second  
>> Life uses unit quaternions, which would normally be expressed as four  
>> real numbers.
>>
>> As far as I can tell, the Message_Layout page is correct -- it should  
>> be 16 bytes, or four F32 values.
>>
>> What makes you say it's only 12? The AgentUpdate message is zerocoded  
>> --  are you perhaps getting misled because zero values are compressed?
>>
>> Q
>>
>>
>>
>> On Feb 17, 2008, at 8:19 PM, Thomas Grimshaw wrote:
>>
>>> Secondly, LLQuaternions
>>>
>>> Could somebody please update this wiki page:
>>>
>>> http://wiki.secondlife.com/wiki/Message_Layout
>>>
>>> to describe the correct LLQuaternion specification. That page  
>>> describes it as 16 bytes, however it seems both the official client  
>>> and LibSL sends 12 bytes in the AgentUpdate packet. What gives?
>>
>>
> 
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