physic engines speed tests

[Chris Hager]

Joshua Minor wrote:
>
> On Mar 18, 2008, at 9:48 AM, Chris Hager wrote:
>>>
>>> How do the physics models themselves compare?
>>
>> The only difference I noticed so far is that Box2D calculates in MKS 
>> (meter-kilo-seconds), and we have to do the translation to pixels by 
>> hand.
>
> I have noticed that Chipmunk never seems to settle all the way, it 
> stays jittery even when nothing should be moving.  Box2D only gets 
> jittery when objects are under a lot of pressure.  Also, Box2D now 
> supports a flag to enable continuous collision detection.  This can 
> prevent high velocity objects from tunneling through thin objects.

The not settling thing is a problem with chipmunks elasticity settings - 
elements only stop moving if it is set to 0.0.

Also I noticed, that Box2D with SWIG crashed on more than ~ 520 elements.

- Chris


Btw, I've added some graphs to [[Physic_Engines/Speed_Tests]], 
displaying the FPS in relation to the count of elements on a XO-B4 (test 
with circles and with polygons).