Sunday, May 17, 2020

Digest for comp.lang.c++@googlegroups.com - 25 updates in 5 topics

Tim Rentsch <tr.17687@z991.linuxsc.com>: May 14 06:55AM -0700


> [...]
 
> You need new eyes. Yours (as provided by your father and mother) do
> not see anything beyond 60 FPS.
 
Not true. Tests done with pilots, using flight simulators, found
that pilots could easily tell that 60 FPS wasn't fast enough to
be realistic.
 
> This announcement is like the ads for some loudspeakers boasting 30
> khz frequency range when your ear doesn't go beyond 17khz. The rest
> is only audible by your dog...
 
Also wrong, although for different reasons. First frequency
response of human ears differs a lot for different individuals,
and tests have been done that found, for some people, even though
their response drops off in the low 20's of kHz it picks up again
in the high 30's of kHz. Second there is an unstated assumption
that if we can't hear sine waves above 20 kHz then there is no
perceptible information content above 20 kHz. This assumption is
known to be false. Time delays are perceptible down into the
range of a small number of microseconds, translating to
frequencies on the order of 200 kHz. These things have been
known for decades, but some engineering types keep repeating the
same bogus assertions about what frequency response is needed,
etc.
jacobnavia <jacob@jacob.remcomp.fr>: May 13 10:01AM +0200

Le 08/05/2020 à 23:18, Mr Flibble a écrit :
> neoGFX achieves 944 FPS:
 
> https://camo.githubusercontent.com/d32e8fabf762b33adbf4f18f447f3530b9b66fd6/687474703a2f2f6e656f6766782e6f72672f74656d702f6c6f6c2e706e673f69643d31
 
> /Flibble
 
OK, at 944 FPS you need a monitor with latency of 1ms. The best monitors
have a latency of 11-12 ms
 
The best monitors have a display rate of 120 FPS...
 
HDMI doesn't cut it beyond 60 FPS, the 120 HDMIs send two frames in one
packet, cheating. You need a display port that goes to 144 FPS (maybe)
 
You need new eyes. Yours (as provided by your father and mother) do not
see anything beyond 60 FPS.
 
This announcement is like the ads for some loudspeakers boasting 30 khz
frequency range when your ear doesn't go beyond 17khz. The rest is only
audible by your dog...
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 12 12:42PM -0700

On 5/11/2020 2:36 PM, Mr Flibble wrote:
 
>> Can you see this animation on your end? It should get 60 fps...
 
> I have very little free time these days even during the COVID-19
> lockdown (which doesn't really change things for a programmer). :D
 
Indeed! :^) Afaict, ShaderToy tries to throttle everything down to 60 fps.
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 12 11:19PM -0700

On 5/12/2020 11:18 PM, Chris M. Thomasson wrote:
>>> I should say that sem_wait returns -1 and errno can be EINTR.
 
>> That's experimental code. EINTR normally doesn't happen.
 
> lol. Okay... Whatever. Anyway, your code works in a Relacy test unit. :^)
 
The test unit makes me have to add the dtor to your code. Also, it makes
me have to make your code handle EINTR from sem_wait. It actually
simulates that.
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 12 11:18PM -0700

On 5/12/2020 11:09 PM, Bonita Montero wrote:
>> I should say that sem_wait returns -1 and errno can be EINTR.
 
> That's experimental code. EINTR normally doesn't happen.
 
lol. Okay... Whatever. Anyway, your code works in a Relacy test unit. :^)
Bonita Montero <Bonita.Montero@gmail.com>: May 12 11:10PM +0200

>> Sorry, that's like debugging hello world. Read the code and you'll
>> see in 10min that is correct (aside from non-handled resource-erors).
 
> Na. I read the code in detail during the porting process.
 
Which porting-process ?
The code is compilable for Windows and Linux.
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 13 04:29PM -0700

On 5/13/2020 7:02 AM, Bonita Montero wrote:
>>> puprose it is completely adequate.
 
>> If it doesn't need to be correct it can be arbitrarily simple and fast.
 
> It wouldn't be slower if it would be correct.
 
That is a strange comment to me. Humm...
Bonita Montero <Bonita.Montero@gmail.com>: May 12 11:14PM +0200

>> Sorry, that's like debugging hello world. Read the code and you'll
>> see in 10min that is correct (aside from non-handled resource-erors).
 
> Na. I read the code in detail during the porting process.
 
I just think that if you add additional code, the timing of
the spinning will change, that Öö Tiib could get into trouble
to prove what he assumes.
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 12 01:51PM -0700

On 5/12/2020 1:49 PM, Bonita Montero wrote:
> Here's again the mutex with adjustable spin-count an the benchmark:
[...]
 
Thank you! Okay, will bust out Relacy and port it. Sometime today, or
tomorrow.
"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: May 12 03:36PM -0700

On 5/12/2020 1:49 PM, Bonita Montero wrote:
> #elif defined(__unix__)
>     sem_wait( &sem );
>
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)