-"Cronus or Kronos in Greek mythology,
identified with the Roman deity Saturn, was the leader and the youngest of the first generation of Titans, divine descendants of Gaia and Ouranos (Earth & Sky).He overthrew his father and ruled during the mythological Golden Age, until he was overthrown by his own sons, Zeus, Hades, and Poseidon, and imprisoned in Tartarus or sent to rule the paradise of the Elysian Fields.
The etymology of the name is obscure.
It may be related to 'horned', suggesting a possible connection with the ancient Indian demon Kroni or the Levantine deity El."
chrono - 'alchemical element', 'control of time and space'-"Chronos or Khronos (Time), not to be confused with Cronus - a Titan,
was imagined as an incorporeal god, serpentine in form, with three heads. Some of the English words with this etymological root include chronology, chronic, chronicle."
Frame Rate Independence
(Open Source - BULLET PHYSICS LIBRARY, Physics Symulation
Forum)
Aug 28, 2008
>>"I
used the term "newbies" to refer to simple
apps.."
- you are right, sorry...
i did exaggerate there a bit because i was struggling to
prove my point otherwise ..i felt it was worth it
>>"BTW,
in the end, it looks like Bullet works exactly as i
expected, and the only problem seems to have been
communication"
- yes, terminology.. but, thats where my
question only begins really..
>>"The
(dt,0) way works correctly."
- you on to it,
(dt,0) does work (as i expect at least) and we needed to
establish that, so we all exactly know what *visually* we
are talking about and can move on.. compare that with
*interpolation*, that is (dt, n>1)
you can try (dt, 10or50or100..), overload your scene and tell us what happens and what did you expect to happen, if you will? [when i do that i notice everything slows down and i expect similar output as with (dt, 0)]
//---------------
terminology explained:
if you're reading this to get an answer to the original
question "Frame Rate Independence",
and by now you only got even more confused..
note that there are
- simulation frames, simulation frame rate = simulation
speed or rate of physics update
- animation frames, animation frame rate = animation
speed or FPS
they go so closely together,
no wonder it confuses so many people... btw answer to my
1st Q. is NO... surprised, eh?
look,
"Frame Rate" in this conversation meant few
things, depending on who was talking it could be:
1.) simulation speed
2.) animation speed
3.) deltaTime
when i say "Frame Rate" i mean "animation
frame-rate", animation speed or FPS like most of us
apparently, hence confusion
by "Frame Rate Independence" i meant:
animation speed may VARY, but Simulation_Flow can still
appear CONSTANT in real time
to me, this is only
independence that makes sense talking about,
im really failing to see of what importance or relevance
is any other independence and how was it not obvious what
is common expectation, common terminology and what would
be likely error
thanks for sharing
Aug 28, 2008
its good to have
someone to talk to about this... cheers!
i still have no idea if iam reporting a bug or my stupidity here.. anyway, ok, that looks all good to me.. not really testing the case in question?
i wonder what kind of
effect could have *video driver* setting that would lock
FPS to Vsync , you know that option:
1.) let application decide
2.) always
3.) never
thanks,
friendly zebra
Aug 28, 2008
thanks.. ok,
i see all that.. something... numbers... submarines...
rainbows
it all looks fine,
except that little bit there which is horribly wrong, so
maybe some problem in the test?
your comment is most
valuable to me... i dont absorb numbers well and im not
really sure whats happening there with all these threads
and sleep() stuff.. how many processors/cores, what
hardware is that?
appreciated
[edit:]
man, that was super-quick, how wonderful ..anything i can
do for you? crunching..........
>>"Passing
maxSubsteps=0 should result in an exception being thrown,
or something similar."
- ok, you lost me there...
//--------------------
To Whom it may concern...
CcdPhysicsDemo has this bit of code:
int
maxSimSubSteps = m_idle ? 1 : 1;
if (m_idle) dt = 1.0/420.f;
int numSimSteps = 0;
numSimSteps =
m_dynamicsWorld->stepSimulation(dt,maxSimSubSteps);
a) all that change to
this:
m_dynamicsWorld->stepSimulation(dt,
0);
b) then to this:
m_dynamicsWorld->stepSimulation(dt,
10or50or100..);
then try to overload the scene eg. resize to full-screen,
add more objects, add empty loop to eat your time
randomly or whatever ..and then compare a) and b)
...visual observation would suffice
Aug 28, 2008
i dont understand
anything anymore...
are you not the same person whom Erwin wrote:
>>"Again, if you want to manage time
and substepping yourself, with similar behaviour to ODE,
disable substepping, don't use/create motion states and
use stepSimulation(deltaTime,0);"
and you said:
>>"Yes, thanks a lot, it helped. I've
been reading so many different ways to do the same thing,
that i didn't know which one to choose. The (dt,0) way
works correctly. I've implemented the helloWorld.."
..which basically means that you already used
maxSubsteps=0 successfully - its a special case ..so,
no.. it what they call variable time_flg_adfk .. i give
up
Divina Commedia, abysm spirale
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