[Lazarus] Threads and Libraries (dll and so)

[Michael Van Canneyt]

On Tue, 4 Feb 2014, Reimar Grabowski wrote:

> On Tue, 4 Feb 2014 15:59:07 +0100 (CET)
> Michael Van Canneyt <michael at freepascal.org> wrote:
>
>> Traditional Film uses 24 FPS, this was considered twice the speed of what was/is
>> needed to experience motion 'fluently'.
> It is not unusual to show the same frame three times to bring the
> framerate up to 72fps to reduce the "black screen time" which will be
> percieved as flickering.  Motion blur helps a lot to make the experience
> 'smooth'.  Why do you think it is recreated in 3D graphics?

Not arguing with that.

>
>> The human eye can *discern* changes at faster rates, meaning it will
>> recognize the difference between a film played at 30 and 60, the latter
>> being perceived as more 'smooth'.
> And the general human can see changes up to 150 fps so the eyes must be able to "see at that rate".

Not arguing with that either.

>
>>
>> But this does not enable you to process the *information* displayed at such a speed.
> As stated in my last mail the USAF and their pilots do not share your opinion.

Please... These people are primed for this kind of thing.

>
>> using a practical example:
>> Let me display random numbers at speed > 10 FPS on screen.
>> Will you be able to repeat the numbers ? I doubt it.
> That's no argument, that's speculation.

Not really. Tests show that:

Average reaction time on an emergency situation in e.g. a car is 1 second, more often 2 seconds.

Here is another one, grabbing a ruler:
http://virtuallabs.stanford.edu/tech/images/ReactionTime.SU-Tech.pdf
It shows reaction times of 0.1 seconds as "fast"

Another one, stating 215 milliseconds (0.2 sec) as median click reaction time:
http://www.humanbenchmark.com/tests/reactiontime/

I'm assuming that the purpose of displaying 20 videos simultaneously is so people can 
react on it, not simply to induce epilepsy attacks. Hence my conclusion that 10FPS is 
ample for a GUI - take even 24 FPS if you prefer.

The point was simply that this relatively low speed does not warrant thread-aware GUIs.

Michael.