Re: [simspark-devel] Timer Test Report

[Joschka B. <jbo...@un...>]

Hi Markus,
> Hi,
>
> Markus Rollmann wrote:
>   
>> Joschka Boedecker wrote:
>>     
>>> * It seems evident that we have to optimize the physics somehow. We 
>>> should at least get to the point where 3 vs. 3 robots can be reliably 
>>> simulated, I think. Without having done any profiling at all, my 
>>> suggestion would be to take a look at possibilities to optimize the 
>>> collision detection in the ODE part. One possibility is to use separate 
>>> collision spaces for each robot. From the ODE Wiki [1]:
>>>       
>> [...]
>>     
>
> [...]
>   
>> I think there are only very few changes necessary:
>>
>> - It is already possible to create the additional 'Space' nodes in the 
>> .rsg files. So putting each robot into it's own collision space would be 
>> a matter of enclosing the current soccerbot.rsg into an additional (node 
>> space ) expression or using an external wrapper .rsg that imports the 
>> soccerbot.
>>
>> - The problem is registering the ODE geoms to the proper space. This is 
>> done in the OnLink() method of the collider class. It calls GetSpaceId() 
>> wich in turn calls OdeObject::GetSpace(). Currently the global Space 
>> object below the SceneServer is returned.
>>
>> This behavior could be changed to walk the parent chain of the ODEObject 
>> in order to find the closest Space parent. If this fails we revert to 
>> the current behavior and return the default space. Therefore existing 
>> .rsg files will still work as expected.
>>
>> - The actual collision logic needs very little change. The wiki entry 
>> [1], that Joschka linked to provides a code snipped that we could nearly 
>> copy 1:1 into our code base.
>>
>> I'll try to implement these changes in the simspark CVS.
>>     
>
> The changes are now part of the simspark CVS trunk. 

Wow, you are fast! Thanks a lot :-D

> I did test the 
> changes with rsgedit and the jointtest.rsg demo, where I placed each 
> hinge2thing.rsg, sliderthing.rsg and universalthing.rsg in a separate 
> space each- and it worked fine ;)
>
>   

Nice :-)

> The problem was not in the setup of the different collision spaces but 
> in the deconstruction of them.
>
> The problem is that all ODE objects should be deconstructed in the 
> proper order. [...]
>
> I'm not sure if it's necessary to copy this whole machinery to the 
> rcsssrver3d CVS, maybe some special handling for agent disconnect will 
> suffice?
>   

Yes, maybe you're right and we can handle this in an easy way somehow 
for the agent disconnects. I'll take a look after I'm back from 
JapanOpen, but if anybody else wants to have a look in the meantime -- 
feel free ;-)

Cheers,
Joschka