Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.sys.apple2.programmer > #3451 > unrolled thread

Colour switching on an Apple IIe?

Back to article view | Back to comp.sys.apple2.programmer

Contents

  Colour switching on an Apple IIe? rickyh <rick.hohler@gmail.com> - 2017-04-30 14:00 -0700
    Re: Colour switching on an Apple IIe? roger.shimada@gmail.com - 2017-04-30 21:52 -0700
      Re: Colour switching on an Apple IIe? Michael J. Mahon <mjmahon@aol.com> - 2017-05-01 01:26 -0500
      Re: Colour switching on an Apple IIe? Michael Pohoreski <michael.pohoreski@gmail.com> - 2017-05-01 06:07 -0700
        Re: Colour switching on an Apple IIe? D Finnigan <dog_cow@macgui.com> - 2017-05-01 21:10 +0000
          Re: Colour switching on an Apple IIe? Michael Pohoreski <michael.pohoreski@gmail.com> - 2017-05-01 14:42 -0700
            Re: Colour switching on an Apple IIe? mmphosis <mmphosis@macgui.com> - 2017-05-02 07:54 +0000
              Re: Colour switching on an Apple IIe? Michael Pohoreski <michael.pohoreski@gmail.com> - 2017-05-02 10:18 -0700
            Re: Colour switching on an Apple IIe? mmphosis <mmphosis@macgui.com> - 2017-05-02 19:00 +0000
        Re: Colour switching on an Apple IIe? Anthony Lawther <alawther@spammenot.mac.com> - 2017-05-02 12:47 +0900
          Re: Colour switching on an Apple IIe? Michael J. Mahon <mjmahon@aol.com> - 2017-05-02 15:55 -0500
        Re: Colour switching on an Apple IIe? James Davis <JPD.Enterprises@live.com> - 2017-05-02 00:33 -0700

#3451 — Colour switching on an Apple IIe?

I was reading this article about colour switching on a C64. Is this possible on an Apple IIe?

http://www.aaronbell.com/secret-colours-of-the-commodore-64/

Thanks
Rick

[toc] | [next] | [standalone]

#3453

I didn’t care for that article at all..the author isn’t very technical and I found “A typical 8-bit computer could only display sixteen colours” a strange thing to have written.

The technique works because people see around 24 frames per second, the effective frame rate of film. (Film is often shown at 48 frames per second, each frame being displayed twice.)

Anyway, yes, it should be possible to display more than 16 colors on an Apple //e with page flipping. This is possible by checking $C019, the //e vertical blank register.

The //c vertical blank works differently so using the Mouse firmware to generate interrupts is recommended; see http://www.1000bit.it/support/manuali/apple/technotes/aiic/tn.aiic.9.html

[toc] | [prev] | [next] | [standalone]

#3454

<roger.shimada@gmail.com> wrote:
> I didn’t care for that article at all..the author isn’t very technical
> and I found “A typical 8-bit computer could only display sixteen colours”
> a strange thing to have written.
> 
> The technique works because people see around 24 frames per second, the
> effective frame rate of film. (Film is often shown at 48 frames per
> second, each frame being displayed twice.)
> 
> Anyway, yes, it should be possible to display more than 16 colors on an
> Apple //e with page flipping. This is possible by checking $C019, the //e
> vertical blank register.
> 
> The //c vertical blank works differently so using the Mouse firmware to
> generate interrupts is recommended; see
> http://www.1000bit.it/support/manuali/apple/technotes/aiic/tn.aiic.9.html
> 

And this "time domain dithering" works even better if the two dither colors
are fairly close in luminance. That minimizes the flicker. 

-- 
-michael - NadaNet 3.1 and AppleCrate II:  http://michaeljmahon.com

[toc] | [prev] | [next] | [standalone]

#3455

On Sunday, April 30, 2017 at 9:52:20 PM UTC-7, roger....@gmail.com wrote:

> The technique works because people see around **a minimum of** 24 frames per second

**FTFY.**

Gamers, like myself, see up to 100+ frames a second.  24 is the average _bare_ minimum for for "smooth" motion.  i.e. Fighter Pilots see up to 200 frames per second -- http://amo.net/nt/02-21-01fps.html

I use the word "smooth" in quotes because to me, and others, anything less then 60 frames/second looks stuttery as hell -- I greatly prefer 100 to 120 frames/second as I can tell **instantly** when the frame rate drops below 60 fps when gaming.

Here is an example of a camera pan that shows just how utterly crappy 24 fps is:

* OWE my eyes @ 24 fps !
http://red.cachefly.net/learn/panning-24fps-180.mp4



* Silky smooth @ 60 fps !

http://red.cachefly.net/learn/panning-60fps-180.mp4

Note that RED makes high-end digital cameras costing $200,000+.  It is a pity they didn't include one at 120 fps for comparison.

The fact that 24 fps looks like crap to some of us is the reason professional first-person-shooter gamers use 120 Hz, or FreeSync (AMD), or GSync (Nvidia) solutions.

You can also test your own eyes/brain/monitor at Blur Busters:
https://www.testufo.com/#test=framerates


> the effective frame rate of film.

Not just effective -- 24 fps IS the frame rate of film.

Sadly we have 24 fps for film, 29.97 for NTSC, and 25 Hz for PAL because people were too stupid to settle on ONE standard.  They literally had no vision or foresight on how to do it properly -- they just hacked solutions that were "good enough" and shipped it and set back progress by half a century.  Instead of listening to the wisdom of the Babylonians, or even talking to a Astronomer, and picking 60 Hz like anyone with a half-a-brain would have done they picked this oddball timings.

/Oblg. xkcd
https://xkcd.com/927/

> Film is often shown at 48 frames per second

Which is STILL shit due to it being < 60 fps.  If they had picked 96 Hz (24 * 4) then that would be reasonable but doubling or quadrupling the frame rate showing the SAME frame is STILL not fixing the fundamental problem of under-sampling in the first place!

As the VR guys are learning the hard way dropping below 90 Hz is painful.

At least Sony is finally getting the clue stick and forcing 60 fps as a bare minimum for VR -- Thank God that they are also telling people to try to target 120 Hz.
https://www.polygon.com/2016/3/17/11256142/sony-framerate-60fps-vr-certification

Getting this back on-topic.

Switching colors fast enough is an "old-skool" demo effect and get used everywhere. e.g. This was done on the HP48S/GX calculators to get 4 levels of grayscale instead of the monochrome with certain games.

Sadly, one can count on one hand the total Apple 2 demos that even attempt this.  The "Rainbow" demo is probably the best example -- but they aren't showing any "new" colors just mixing GR and HGR colors!

It would be interesting to work out the timing

- without VSync
- with VSync

and see (pardon the pun) if we get any "new" colors.  Especially with DHGR.

[toc] | [prev] | [next] | [standalone]

#3456

Michael Pohoreski wrote:
> On Sunday, April 30, 2017 at 9:52:20 PM UTC-7, roger....@gmail.com wrote:
> 
>> The technique works because people see around **a minimum of** 24 frames
>> per second
> 
> **FTFY.**
> 
> Gamers, like myself, see up to 100+ frames a second.  24 is the average
> _bare_ minimum for for "smooth" motion. 

Do you get 100+ frames per second on your Apple II gaming rig?

-- 
]DF$
Apple II 40th Anniversary User's Guide:
http://macgui.com/newa2guide/

[toc] | [prev] | [next] | [standalone]

#3457

Of course not -- no one was claiming otherwise.
Just clarifying why film's 24 frames/sec sucks.

At least we can get page-flipping and 29.97 Hz animation for free on the Apple //e. :) Which means we might be able to predict and even produce a simulator on other platforms to approximate the real effect.  And even account for the 25 Hz PAL Apples.

I'm curious to know what colors we end up when we sit in s tight spin lock loop.

I.e. It would be nice to see some "extra" colors like the C64 demo scene guys get. :)

[toc] | [prev] | [next] | [standalone]

#3462

Michael Pohoreski wrote:
> I'm curious to know what colors we end up when we sit in s tight spin lock
> loop.

http://www.applefritter.com/files/120colors.png

[toc] | [prev] | [next] | [standalone]

#3464

On Tuesday, May 2, 2017 at 12:57:48 AM UTC-7, mmphosis wrote:
> Michael Pohoreski wrote:
> > I'm curious to know what colors we end up when we sit in s tight spin lock
> > loop.
> http://www.applefritter.com/files/120colors.png

Page not found. :-(

Any mirrors?

[toc] | [prev] | [next] | [standalone]

#3465

http://www.applefritter.com/files/images/120colors_0.png

http://www.applefritter.com/?q=content/120-colors

[toc] | [prev] | [next] | [standalone]

#3459

Michael Pohoreski <michael.pohoreski@gmail.com> wrote:

<snip>

> Not just effective -- 24 fps IS the frame rate of film.
> 
> Sadly we have 24 fps for film, 29.97 for NTSC, and 25 Hz for PAL because
> people were too stupid to settle on ONE standard.  They literally had no
> vision or foresight on how to do it properly -- they just hacked
> solutions that were "good enough" and shipped it and set back progress by
> half a century.  Instead of listening to the wisdom of the Babylonians,
> or even talking to a Astronomer, and picking 60 Hz like anyone with a
> half-a-brain would have done they picked this oddball timings.

Hindsight is 20/20. The development of these standards happened in parallel
with no expectation of convergence. NTSC originally refreshed at 60Hz and
was shifted down to 59.94Hz with the introduction of colour. PAL included
colour from the start. Each of these standards were synchronized with the
power frequency in use in the area used as this solved the problem of
distributing a frequency reference to the receivers. 

Similarly film frame rates were governed by the hand crank speed of cameras
until sound was included. 24 fps, with double or triple shuttering, appears
to have been selected as it fell in the range used for silent films and
Edison said that 46 fps was the minimum required by the visual cortex. 

To suggest that the people who pioneered motion pictures should have used
60 fps for compatibility with a technology that didn't exist yet is like
being upset at Apple for not including USB ports on the IIc. 60 fps would
have given less than 5 minutes per 1000 foot reel of film. 

PAL vs NTSC frequencies is down to power systems which also predates the
concept of television. 

So, feel free to point out these peoples' inability to accurately predict
the future (a universally human condition) but please don't call them or
their choices stupid. 
> 
> /Oblg. xkcd
> https://xkcd.com/927/

Not really appropriate to this particular matter. 

<snip>

Regards,
Anthony. 

[toc] | [prev] | [next] | [standalone]

#3466

Anthony Lawther <alawther@spammenot.mac.com> wrote:
> Michael Pohoreski <michael.pohoreski@gmail.com> wrote:
> 
> <snip>
> 
>> Not just effective -- 24 fps IS the frame rate of film.
>> 
>> Sadly we have 24 fps for film, 29.97 for NTSC, and 25 Hz for PAL because
>> people were too stupid to settle on ONE standard.  They literally had no
>> vision or foresight on how to do it properly -- they just hacked
>> solutions that were "good enough" and shipped it and set back progress by
>> half a century.  Instead of listening to the wisdom of the Babylonians,
>> or even talking to a Astronomer, and picking 60 Hz like anyone with a
>> half-a-brain would have done they picked this oddball timings.
> 
> Hindsight is 20/20. The development of these standards happened in parallel
> with no expectation of convergence. NTSC originally refreshed at 60Hz and
> was shifted down to 59.94Hz with the introduction of colour. PAL included
> colour from the start. Each of these standards were synchronized with the
> power frequency in use in the area used as this solved the problem of
> distributing a frequency reference to the receivers. 
> 
> Similarly film frame rates were governed by the hand crank speed of cameras
> until sound was included. 24 fps, with double or triple shuttering, appears
> to have been selected as it fell in the range used for silent films and
> Edison said that 46 fps was the minimum required by the visual cortex. 
> 
> To suggest that the people who pioneered motion pictures should have used
> 60 fps for compatibility with a technology that didn't exist yet is like
> being upset at Apple for not including USB ports on the IIc. 60 fps would
> have given less than 5 minutes per 1000 foot reel of film. 
> 
> PAL vs NTSC frequencies is down to power systems which also predates the
> concept of television. 
> 
> So, feel free to point out these peoples' inability to accurately predict
> the future (a universally human condition) but please don't call them or
> their choices stupid. 
>> 
>> /Oblg. xkcd
>> https://xkcd.com/927/
> 
> Not really appropriate to this particular matter. 
> 
> <snip>
> 
> Regards,
> Anthony. 
> 

Well said, Anthony--I was tempted to respond similarly. ;-)

One small correction: matching the frame rate to the power line frequency
wasn't a matter of getting a frequency reference, but a matter of avoiding
annoying movement of power line frequency interference in the picture. 

This requirement was somewhat relaxed when moving to NTSC color, but the
deviation was kept small enough that power-synced noise did not move
quickly. With improvements in power supply design and the demise of vacuum
tubes (except the CRT) and their AC heaters, power line interference became
much less of a consideration. 

-- 
-michael - NadaNet 3.1 and AppleCrate II:  http://michaeljmahon.com

[toc] | [prev] | [next] | [standalone]

#3461

Hi Michael,

> * OWE my eyes @ 24 fps ! 
> http://red.cachefly.net/learn/panning-24fps-180.mp4
> * Silky smooth @ 60 fps !
> http://red.cachefly.net/learn/panning-60fps-180.mp4 

Both of these look the same (jittery) in windows media player.  But the first looks more blurry than the second.

James Davis

[toc] | [prev] | [standalone]

Back to top | Article view | comp.sys.apple2.programmer

csiph-web