CPCWiki forum

General Category => Demos => Topic started by: krusty_benediction on 16:58, 18 January 17

Title: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 16:58, 18 January 17
Hello


I think I have not a strong enough knowledge of works of the eighties (end even nineties in fact).
I'd like to watch old demos which made advance some points of demomaking methods (a new effect, a new method, a new record, ...) and I have to admit that I do not know which prod to view or where to search.

Is there any resources retracing the history of CPC demomaking ? or its breakthrough ?
If yes, I'd like to access them.
If no, I may be ready to gather your knowledge to track these state of the art demos.

Thanks
Title: Re: History of Amstrad CPC Demomaking
Post by: villain on 18:04, 18 January 17
Impulsively I'd like to nominate Gozeur's Plasma Demo. Early 90s probably.
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 21:08, 18 January 17
Impulsively I'd like to nominate Gozeur's Plasma Demo. Early 90s probably.
yes, need to add this ; I'll look inside the loader if we can find a release year if nobody remembers
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 21:28, 18 January 17
'the demo' - first with a musical loader I think.
http://www.cpc-power.com/index.php?page=detail&num=8746

'logon revolution demo' - first with a split raster?
http://www.cpc-power.com/index.php?page=detail&num=7799

dma plus demo (first with dma music I think)
http://www.cpc-power.com/index.php?page=detail&num=8874

is this the first overscan using splitting?
http://www.cpc-power.com/index.php?page=detail&num=8010
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 21:35, 18 January 17
possibly the first that uses mode 2 and dither to create more colours:

http://www.cpc-power.com/index.php?page=detail&num=7561

one part also uses "interlace sync and video mode" which seems to work on type 1 only.

not sure when rasters were first done, but this is early:

blink soft demo 3
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 21:49, 18 January 17
I always liked this one and it uses the '32kb' screen. Rasters from vorspann or maybe vorspann was after?

exocet jupiter bdr 2

I always like the sampler stuff by dragonbreed.
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 21:52, 18 January 17
There was one more I liked which had rasters, a scroller, and had sampled drums.
I believe it was converted by Weee and it was based on a c64 demo.
I can't find it now. I thought it was part of the Terrific Demo but I'm not so sure now.

Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 23:51, 18 January 17
'the demo' - first with a musical loader I think.
http://www.cpc-power.com/index.php?page=detail&num=8746 (http://www.cpc-power.com/index.php?page=detail&num=8746)

'logon revolution demo' - first with a split raster?
http://www.cpc-power.com/index.php?page=detail&num=7799 (http://www.cpc-power.com/index.php?page=detail&num=7799)

dma plus demo (first with dma music I think)
http://www.cpc-power.com/index.php?page=detail&num=8874 (http://www.cpc-power.com/index.php?page=detail&num=8874)

is this the first overscan using splitting?
http://www.cpc-power.com/index.php?page=detail&num=8010 (http://www.cpc-power.com/index.php?page=detail&num=8010)

Is revolog also the 1st with vertical scroll ?
I do not know Final Creation ; will transfer it this week end
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 23:57, 18 January 17
possibly the first that uses mode 2 and dither to create more colours:

http://www.cpc-power.com/index.php?page=detail&num=7561 (http://www.cpc-power.com/index.php?page=detail&num=7561)

one part also uses "interlace sync and video mode" which seems to work on type 1 only.

not sure when rasters were first done, but this is early:

blink soft demo 3

I do not know "blink soft demo 3" ; I'll watch this week end too
it seems to be available there http://cpcrulez.fr/demostestDO_blinksoft-demo_3.htm (http://cpcrulez.fr/demostestDO_blinksoft-demo_3.htm)

BSC could be able to find the date
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 00:00, 19 January 17
I always liked this one and it uses the '32kb' screen. Rasters from vorspann or maybe vorspann was after?

exocet jupiter bdr 2

I always like the sampler stuff by dragonbreed.

once again, I do not know that ; I'll transfer it this week end
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 00:14, 19 January 17
S&KOH of course for the first RVI http://www.cpc-power.com/index.php?page=detail&num=7591 (http://www.cpc-power.com/index.php?page=detail&num=7591)

but what about the :
 - first hardware scroller
 - first line to line splitting
 - first sample
 - ...
?
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 09:21, 19 January 17
Is revolog also the 1st with vertical scroll ?
I do not know Final Creation ; will transfer it this week end
revolog: yes it could be.
final creation: it is a classic to me, with the big eyes, big scroller and rasters.

Another good one is kkb's first. Uses mode 2 for the text and split rasters to change the colours at the beginning. It's got many splits, uses r2 for the logo, has scrolling and lots of other bits. I don't think it's the first to do this.

I was going to say 'the demo' was the first to be a megademo, but I think there were others before this, perhaps 'amazing demo'.

I think 'Face Hugger's Megademo' is worth noting. It has interlace, it's bobs, it has lemmings, it has 3d.

Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 09:22, 19 January 17
once again, I do not know that ; I'll transfer it this week end
I can't find vorspann. It was a demo creator (I think nwc's demo maker may be the first). It had a raster movement which you will see in exocet's demo (exocet's demo is very simple but it may be the first to use this type of overscan).

Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 09:27, 19 January 17
S&KOH of course for the first RVI http://www.cpc-power.com/index.php?page=detail&num=7591 (http://www.cpc-power.com/index.php?page=detail&num=7591)

but what about the :
 - first hardware scroller
 - first line to line splitting
 - first sample
 - ...
?
esc did some samples - I think one says 'RAX' or something like that  ;D
I can't remember if it's in the twinblast demo or not. I don't think it's the first.

Here this sample is 4-bit, I think earlier stuff (around 1985) was 1-bit sampled from cassette.

First hardware scroll, technically, is probably one of them amiga boing demos from 1985.
It's not a hardware scroll with message, but all directions to make the ball bounce.

Gozeur's plasma is an example of line-to-line splitting. I am trying to think if there is something earlier. Certainly Thriller produced some nice effects. The Terrific Demo had a 'bitplanes' part. BSC in his megademo used r8 to do a scroller.

Looking on cpc-power I saw there are quite a few early ones using r2 to distort.

Some of the demos I quoted I saw back when they were released when I was swapping with Warlock and some I saw from UK PD library 'Penguin Software'.



Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 09:29, 19 January 17
S&KOH of course for the first RVI http://www.cpc-power.com/index.php?page=detail&num=7591 (http://www.cpc-power.com/index.php?page=detail&num=7591)

but what about the :
 - first hardware scroller
 - first line to line splitting
 - first sample
 - ...
?
Overflow produced some nice coding here.
The first part uses what I call 'horizontal splitting'. I think that is RVI? Then the main part uses another technique for the distortion and scrolling of the image.

Is there a list of names for these techniques and a description of what they do so I can know I am using the correct names?
Title: Re: History of Amstrad CPC Demomaking
Post by: roudoudou on 09:40, 19 January 17
Overflow produced some nice coding here.
The first part uses what I call 'horizontal splitting'. I think that is RVI? Then the main part uses another technique for the distortion and scrolling of the image.

Is there a list of names for these techniques and a description of what they do so I can know I am using the correct names?


RVI is a french acronyme for "invisible vertical split" (rupture verticale invisible)


The technic consist in one (or more) split after the visible part of the screen, to jump over lines and choose any memory adress in the video memory for the next displayed line



Title: Re: History of Amstrad CPC Demomaking
Post by: villain on 09:53, 19 January 17
If you want to write the history of demomaking you could possibly try to contact Odiesoft. I think he should remember a lot of things, also from the early years. Another good source could be BSC, you already mentioned him.
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 11:21, 19 January 17

RVI is a french acronyme for "invisible vertical split" (rupture verticale invisible)


The technic consist in one (or more) split after the visible part of the screen, to jump over lines and choose any memory adress in the video memory for the next displayed line
is RVB for the more traditional split?
(rupture verticale bloque)
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 11:24, 19 January 17
I also recommend NWC.

His pc1512 demo has rasters and a scroll but I think the scrolling is software.

http://cpcrulez.fr/demostestDO_NWC-pc_1512.htm

Also take a look at some of the malibu demos (p007). Some of them have software distorted scrollers.

I think the best example of a smooth sinus scroll, and a smooth hardware scroll done by multiple copies offset by a few pixels, see the european meeting demo:

http://cpcrulez.fr/demostestDO_european_demo_party-logon_system__MMPF.htm


Title: Re: History of Amstrad CPC Demomaking
Post by: robcfg on 11:39, 19 January 17
Don't forget @Prodatron (http://www.cpcwiki.eu/forum/index.php?action=profile;u=13) 's productions!
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 12:07, 19 January 17
NoRecess remind me of this:

http://cpcwiki.eu/index.php/History_of_CPC_Demos
Title: Re: History of Amstrad CPC Demomaking
Post by: roudoudou on 12:21, 19 January 17
is RVB for the more traditional split?
(rupture verticale bloque)


There is another acronyme RVMB for multi-block. As there is no (I)nvisible, the split are "visibles", like Offset part for 30YMD

Traditionnal split is Line per line, as you said before, or split if there is only one


EDIT: oh, RVMB is supposed to use same block width

Title: Re: History of Amstrad CPC Demomaking
Post by: villain on 13:54, 19 January 17
NoRecess remind me of this:

http://cpcwiki.eu/index.php/History_of_CPC_Demos

[slightlyofftopic]But Finland never joined the community. NWC actually is from Denmark. Not sure if I should change this inside the article, since it's a translation and the mistake also was in the original.[/slightlyofftopic]
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 15:48, 19 January 17
Ok,
Thanks for all these answers, I'll treat them as soon as possible.
I do not know all these prods.

@arnoldemu (http://www.cpcwiki.eu/forum/index.php?action=profile;u=122) For S&Koh, I was talking of the big rolling picture ; but yes there is a also another technical achievement with the intro
Title: Re: History of Amstrad CPC Demomaking
Post by: TomEtJerry on 20:11, 23 January 17
Hello,

Many "classic" technics as rasters, multimode and hardware scrollers have not been discovered by demo-makers but by game coders. Many programs were using these pieces of code, even early ones.  I suppose some other technics have not been used very often just because they were not really compatible with games' restrictions and loading time on tape:-) (fullscreen).

About new effects, I think "New Age 1" intro  from New age is the first one that uses "border split rasters" trick.
First part with digidrums : In "Amazing demo", a part of Longshot uses "Au revoir Monty" music converted from Atari ST.

Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 21:40, 23 January 17
Hello,

Many "classic" technics as rasters, multimode and hardware scrollers have not been discovered by demo-makers but by game coders. Many programs were using these pieces of code, even early ones.  I suppose some other technics have not been used very often just because they were not really compatible with games' restrictions and loading time on tape:-) (fullscreen).

About new effects, I think "New Age 1" intro  from New age is the first one that uses "border split rasters" trick.
First part with digidrums : In "Amazing demo", a part of Longshot uses "Au revoir Monty" music converted from Atari ST.
I agree. I see that Multi-mode was done very early (1984/85), here changing colour at interrupt position. The same is true with multiple colours, this was early. I haven't seen rasters done well in early games. Zynaps is a bit later than with demos?

I have also seen hardware scrolling used early - doesn't it depend on if you are talking hardware scrolling for graphics or hardware scrolling for text?

I will take a look at new age 1 and amazing demo. I haven't seen these.

The part I was talking about before (with digi drums and music) is Weee!'s Wow part in the Terrific demo.

EDIT: Doesn't trailblazer use raster colour changes to make the scroll? That is 1986.
2d stunt rider is hardware scrolling in 1985/86?
Title: Re: History of Amstrad CPC Demomaking
Post by: AMSDOS on 10:36, 24 January 17
ACU published the game Splatch Nov/Dec '85 (http://www.cpcwiki.eu/index.php/Splatch), which is using Rasters on it's title screen & Hiscore screen isn't it?
Title: Re: History of Amstrad CPC Demomaking
Post by: kawickboy on 10:41, 24 January 17
crafton&xunk (get dexter) out in 1985 used hard scroll wasn't it ?
Title: Re: History of Amstrad CPC Demomaking
Post by: Gryzor on 10:51, 24 January 17
Ah... a timeline with demos and explanations (technical advancements etc) would be something really, really sweet! I've often wondered myself...
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 11:04, 24 January 17
Hello,

Many "classic" technics as rasters, multimode and hardware scrollers have not been discovered by demo-makers but by game coders. Many programs were using these pieces of code, even early ones.  I suppose some other technics have not been used very often just because they were not really compatible with games' restrictions and loading time on tape:-) (fullscreen).

About new effects, I think "New Age 1" intro  from New age is the first one that uses "border split rasters" trick.
First part with digidrums : In "Amazing demo", a part of Longshot uses "Au revoir Monty" music converted from Atari ST.
Nice remark, I never though of games, I'll look at these demos too (but I already know them at least;) )
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 15:53, 24 January 17
ACU published the game Splatch Nov/Dec '85 (http://www.cpcwiki.eu/index.php/Splatch), which is using Rasters on it's title screen & Hiscore screen isn't it?
yes it is.

Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 21:19, 12 February 17
I had not the time time to (re)watch the demos before...

I'm fighting with the maze of the terrific ; is there a way to manually launch a part ?
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 22:04, 12 February 17
I had not the time time to (re)watch the demos before...

I'm fighting with the maze of the terrific ; is there a way to manually launch a part ?
Yes.
look in the downloads section of www.cpctech.org.uk
Here I "hacked" the demo and put all the parts so they can be launched separately.
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 01:08, 18 June 17
Hello All
About splitting technics, the first game using this technique was genocide with the first vertical scroll (using crtc reg 5)
(revolog was not using reg 5, but page flipping combined with offset split. main menu of the demo was using reg 5)
This game also used the dual playfield technique to rapidly display the sprites (only 3 colors in mode 0)
The fisrt multi directional scrolling was in the game "titan" ans was wery fast (because of offset width)
(the first page flipping with crtc to slow down a scroll was in longshot demo).
The first slow down of an hardware scroll with reg 3 was done in the game "skatewars".
The first use of the "replication char line" was in logon demo 3 (vertical raster)
The first primitive crtc detection was done by Remi Herbulot in his crafton & xunk game to scroll horizontally the screen (but crtc 1 was also considered as a crtc 2)
The first overscan screen on cpc was in the logon demo 1 (1988)
About raster splitting i don't remember if trailblazzer was using this technic to display the rolling road.
(I guess it was changing some inks between each scanline, but not changing the same ink many times during the visible scanline)
I think the first multi split (and first line to line split) was in the amazing demo
The first horizontal split technic was done by overflow (s&koh)
The first horizontal gfx mode split was done by gozeur or duncan (5kb).
I don't know who has coded the first rvmb (used in the grim "s&koh" like) (8 crtc split by scan line (8x8=64 nop))
(only on crtc 1. on crtc 0 : a 1/2 nop of border between each split)
I don't remember what was the fisrt demo using the split border technic
I don't know if someone has ever used the gfx mode 3 for a demo effect (it seems useless)
Some program manage tricky variable/evolutive split :
dtc (for the moving scroll), pinball dreams (for the vertical scroll with a fix part in the top of the screen)
Title: Re: History of Amstrad CPC Demomaking
Post by: fgbrain on 09:17, 18 June 17
the first multi direction multi speed smooth hardware scroll  is in game TLL (tornado low level) in 1985....
even Roland in the Caves /Ropes uses 4 direction hw scroll [but not smooth] in 1984.


furthermore, BSC crazyscroll is the first one to display a rasterscroll with gfx screen as background  (1991).
I think Elmsoft in Chain demo has same effect using a different trick...


also btw  the best 3D raster scroll is made by Executioner at Riverscroll demo in 2010


but it would be nice to talk about software techniques as well!!?
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 13:07, 18 June 17
 :-[ Yes, of course, "roland in the caves" and "ttl" used a multi directionnal hardware scroll.
But the first hardware scroll on your cpc is called "locomative basic"...just type "list" in basic.  ;D

About 3d scroll, the first time i've see that in a cpc demo was in 1989 in the pict part for "the demo".

The "rasterscroll with gfx screen as background" is made using crtc to display border (reg 8 on some crtc, or reg 6).
I don't know if bsc was the first one to do that (1991 seems late in retrospect)

If you want to speak also about "software techniques", i think that many cpc games were much more advanced than demoes, even speaking about 3d. (see driller, sentinel,...)
Title: Re: History of Amstrad CPC Demomaking
Post by: krusty_benediction on 18:17, 18 June 17
Hello, thank you so much for these information.

I have to confess I have no more investigated the subject because someone have told me he is writing a book on the subject ; and I do not want to make the same research work in parallel.

I used mode 3 several 1 or 2 times in my demos :
- 30 Years Amstrad Megademo   http://www.pouet.net/prod.php?which=67656 (http://www.pouet.net/prod.php?which=67656) during the intro, in the screen with the parallax scrollers with the names of the participants: I display half of a scroll line by using mode 0 and half by using mode 3 with exactly the same address. T think it was mandatory because I had not enough memory screen available to do that (because there are too many scroller or because I have the code and data of the remaining effects,  I do not remember)
- Wake up ! http://www.pouet.net/prod.php?which=59073 (http://www.pouet.net/prod.php?which=59073) for he screen with the 3 rotozoomed-boxed (but maybe I'm wrong and it is simple rasters)
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 13:32, 22 June 17
Additional to what Longshot wrote:


- BSC was the first to display a doubled vertical resolution screen aka interlaced video, see http://www.cpc-power.com/index.php?page=detail&num=9029 - Displaying a 320 x 400 pixel screen. Must have been around 1989.


AFAIK there has not been anything like the Crazy Scroll effect before BSC Megademo, that is using CRTC register 8 to overlay the screen with the border. That part was written in 1990, I think.
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 00:51, 28 June 17
Quote
Displaying a 320 x 400 pixel screen
It's not a first time because it's not possible on cpc.... ;)
Interlace mode does not run properly on cpc and btw 272 vertical pixels are the maximum displayable
Title: Re: History of Amstrad CPC Demomaking
Post by: GOB on 19:55, 29 June 17
I think also BSC is the first on the BSC megademo (part with crazy cars 2 gfx) to make split border.
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 15:04, 03 July 17
It's not a first time because it's not possible on cpc.... ;)
Interlace mode does not run properly on cpc and btw 272 vertical pixels are the maximum displayable

 :D  But I have done it! On my good old 464. A screen with 400 pixels on the Y-axis. Have you ever had a look at it?

Try it out:

http://cpcrulez.fr/demostestDO_betasoft_demo_7-interlace_demo.htm (http://cpcrulez.fr/demostestDO_betasoft_demo_7-interlace_demo.htm)

It might not work on all machines. And I had to adjust the V-hold control to a very delicate, unstable setting,
BUT: There was a screen made up of 2 (read: TWO) 320x200 screens on top of each other.


PS: to Gryzor: the edit widget sucks.. each time I make a post, line feeds are doubled :/
Title: Re: History of Amstrad CPC Demomaking
Post by: arnoldemu on 16:06, 03 July 17
It's not a first time because it's not possible on cpc.... ;)
Interlace mode does not run properly on cpc and btw 272 vertical pixels are the maximum displayable
Some monitors show more than 272 visible lines. I had one that happily showed 280. ;) It depends on the internal v-size adjustment inside the monitor.

My understanding is that the CPC outputs a progressive signal closer to 288p.
PAL television is 576i interlaced.

The CRTC attempts to make interlace by outputting a VSYNC that is delayed by half a line on odd frames. This passes through the gate-array to the monitor.

What I don't know is if the gate-array passes that through or manipulates it based on hsync. I suspect it changes it and this is why the interlace is not true and the screen moves up and down more.

Then what I don't know is when the monitor receives it, is the IC in the monitor capable of interpreting this and generating a true interlaced screen or not.

So without more investigation and somebody with a scope confirming it or not, I am not going to say yes or no.


Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 23:30, 03 July 17
Quote
A screen with 400 pixels on the Y-axis
Long, long, long time ago in the cpc galaxy, i had displayed some pictures like that (2 pictures from the dart-scanner) and i thought it was 400 lines (demo 4 with "408" lines). But i was wrong, as several demomaker proved in 2006.
The gate array correct the video signal and makes each line odd. So even=odd in interlace mode.
You see two pictures and believe to see 2 lines instead of one when crtc r8=1 and the two video buffers are switched BUT one time the display start one odd line higher (like if R5 was switched between 0 and 1 each vbl) (or like if the screen started in the first line of border).
It's easy to see. You've just to set your crtc reg (interlace mode with 2 screen in mode 2) and just poke some "255" in the video page in the common line of the two screen (i think the line 1 of first screen and line 2 of the other one). Sorry to burst your bubble  :laugh: ..It's just page flipping...
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 00:33, 07 July 17
That sounds reasonable. If I ever find the time, I'll assemble good old Arnold and have a closer look. It's almost impossible that I got so deceived by myself  ;D
Title: Re: History of Amstrad CPC Demomaking
Post by: SyX on 17:59, 07 July 17
I thought interlace was old news, a few ReSeTs ago (i don't remember if it was before or after, i rediscovered how to get new colours in the CPC while i was playing with the front porch in my NTSC compatible tv), Grimm first and then me showed an interlace Fx that it doesn't depend in the CRTC.

The idea is making the first scanline half size during the odd frame. The pseudo-code would be:
1.- Wait vblank
2.- Wait a full scanline, except the time for making a short line (CRTC REG_02 = $12)
3.- Wait half scanline (32 NOPs), although in this moment is a full scanline :P
4.- Reset the scanline to its normal size (CRTC REG_02 = $32)

And that is all, of course you need to repeat that every 2 frames (and don't forget to set the screen pointers).

You can test the attached example in a real machine using a CRT monitor or TV and you will see that is a real interlace where the scanlines from odd frames are not showed over the same scanlines than the even frames, they are shifted.

The test that i made in a few LCDs/Plasma/LEDs/... showed that you don't need to do nothing special for getting an interlace picture, only change the screen pointers every frame, but that is cheating :P
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 20:52, 09 July 17
You mean that with every frame, it's only the hbl of the first scanline that is used to define the vertical position on the monitor?
(BTW, the other lines are linked to the first one.)
That also means that without a sync on the first hbl, the first line is always odd, and with a sync, the first line is always even (or vice-versa).
In other words, the operation occurring during the first hbl bypasses the crtc r8 setting.
It's very interesting.  :P
Need to see that on a real cpc with a ctm monitor.
So if it runs on a ctm monitor, the first interlaced picture would be credited to the person who used this technique.  ;D
 
Title: Re: History of Amstrad CPC Demomaking
Post by: ralferoo on 20:31, 06 August 17
You mean that with every frame, it's only the hbl of the first scanline that is used to define the vertical position on the monitor?
I'm not sure what that question is exactly, but there's an easy way to explain this...


Lines aren't actually horizontal on a CRT, the end of the line is slightly lower than the start of the line. The reason for this is that both the horizontal and vertical deflector plates are continuously charged, just at different rates. Every time there's a horizontal sync, the X plate is discharged from +ve to fully -ve, and every time there's a horizontal sync, the Y plate is discharged from +ve to fully -ve. The rest of the time, the charge on the plates is increasing (the Y plate at a slower rate than the X plate) and the nominal rates are 15625Hz/50Hz (PAL) 16734Hz/60Hz (NTSC) although the actual values aren't especially important - if the charging rate is too slow then the image will be smaller than nominal, if too fast then the image larger than nominal, but in normal use there is a border that provides plenty of slack and the user can centre their image using the horizontal/vertical position knobs (which just add a slight bias to the charge).


In reality, it's not actually the sync pulses from the monitor that cause the plates to be discharged, it's actually the pair of phase locked loops inside the monitor, again one for each plate. The sync pulses are actually just used to correct minor timing glitches in the PLL, so if the centre of the pulse is before or after the centre of the PLL signal, the frequency of the PLL will be slightly adjusted to compensate until they're in sync again. As an aside, this is why horizontal scrolling by adjusting the horizontal sync pulse position can take a few lines to adjust to the correct position if too large a scroll is attempted between lines.


For interlaced, nominally one frame is one line longer than the other, but in truth it's an extra half-line inserted before the vertical sync pulse at the end of one frame and an extra half-line inserted after the pulse at the start of the next frame. This is exactly half of the cycle of the horizontal PLL, so it doesn't affect the horizontal timings (and even if it was adjusted slightly, it'd be corrected in the remaining off-screen lines after the vertical blank), but the extra half line does affect the vertical charging plates - they'll be alternately discharged at the start of a line and the middle of a line. This has the effect of the vertical deflection plate being charged for half a line longer on alternate frames, which means that the electron beam is actually half a line lower on those frames. Thus, interlaced actually genuinely is filling in the gaps between the lines on the previous frame.


SyX's idea to achieve the same effect is to just move the horizontal sync position by 32 cycles, which should work identically, although I'd be tempted to wait for the full length of the VSYNC before restoring the original value. I can't remember now if the CPC output has Vsync and Hsync signals exclusive-ored (like CGA does), but broadcast TV signals have them ored.
Title: Re: History of Amstrad CPC Demomaking
Post by: norecess on 03:06, 22 July 18
Don't know if it can help, but I created a "Amstrad CPC Demoscene Timeline" playlist with my Youtube account: https://www.youtube.com/playlist?list=PLsP9IyH3f1U8FEYYcc3wp73fVVGaaEYfs

Note that I created and uploaded all those videos by myself.
Title: Re: History of Amstrad CPC Demomaking
Post by: Hicks on 15:22, 10 September 18
Some more stuff... With this interview of NWC (http://memoryfull.net/articles.php?id=34), we know that:
- First Overscan/Fullscreen: Final Creation by NWC (June 1988)... And not Logon Demo 2 (end 1988, december probably),
- First Classical Splitting in a demo: Final Creation by NWC (June 1988)... And not Longshot Demo or Revolog (july 1989). The first ever is of course Mission Genocide (mid-1987).
- First Hardware Scroller in a demo: Remix-I by NWC (March 1988)... A lot of hardware scroller were already done in games since 1984.
Coming soon: a list of all these records on Memory Full!
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 22:07, 17 September 18
I did not think I would have had to revisit this topic--where vanity is out of place--but it is necessary to clarify certain points since I'm involved.

It would indeed be a terrible shame to revise the history of the demoscene on a site (or in a book) based on observations taken out of context (or for other obscure reasons).

I created Logon Demos 1, 2, and 3 in February/March 1988 at the Ubi Castle. I released them to local CPC friends and contacts like Brad, who designed the first Logon logos, and I showed them to several C64 users.
I then created Logon Demo 4 (unreleased) around the same time I met Stephane Picq based on our discussions on the CRTC Reg. 8 that he used in his Birdie CPC game.
In early 1989, I finalized and updated some of the text, and several months later, I re-released the demos (1, 2, 3, 5, ‘Longshot’, and 'Revolog') all at once to the CPC scene.

I guess NWC's 1988 demos were only distributed to certain contacts in Denmark and did not arrive in France until later (around late 1989/early 1990).
This explains why a lot of people in the scene--and not just myself--questioned the dates, not seeing how such good demos had not circulated before.
I suppose the relatively limited technical evolution of the Not-Dead Demo, released 2 years after Final Creation, added to the doubt.

Furthermore, I created Anti-Multiface in 1987; it thus makes no sense that I would question the date of a 1988 demo by claiming that Multiface did not yet exist at that time.

Speaking of achievements, as far as i know, Peter was the first guy to create a multi-CRTC CPC (three in the same case).
If I remember well, he made some tests switching from one CRTC to another in real time.
Title: Re: History of Amstrad CPC Demomaking
Post by: Hicks on 23:37, 17 September 18
Shame would be especially to only have one point of view on history. That's why there is all these interviews, and we see that some guys in the past have cheated history in their advantage, because they could express themselves a lot...

About chronology. What is important is release date, I think that everybody will agree with that. Intermediate version dates are unverifiable... Maybe NWC make a first version of Final Creation in the end of 1987, who knows?

In short, it quite amusing to see someone, 25 years later, trying to prove against all evidence that he is the first to do that or that... But don't worry Longshot, you are still the recordman of the most arrogant scrolltext in demos  ;D
Title: Re: History of Amstrad CPC Demomaking
Post by: Longshot on 20:09, 18 September 18
Quote
In short, it quite amusing to see someone, 25 years later, trying to prove against all evidence that he is the first to do that or that...
No need to go back 25 years (30, actually) to find people screeching to get recognized as being the first to do this or that—see for example http://www.pouet.net/prod.php?which=61177  ;D  (http://www.pouet.net/prod.php?which=61177)

In the era of Internet (and post-truth), it would really be a pity if some guys were to cheat history to their advantage because they express themselves a lot.


Just because I don’t have the earliest versions of The Demo anymore doesn’t mean that they weren’t released.


I rest my case.
 
Title: Re: History of Amstrad CPC Demomaking
Post by: Duke on 20:58, 18 September 18
Eitherway, NWC and Longshot are both the legends of early CPC demo making :)
- I think both developed their hardscrolling, splitrasters and split techniques etc. independly at about the same time. In the early days there weren't many foreign demos going around here (in Denmark) and the Danish demos probably didn't spread  abroad as well.
For historical purposes I would say the release date written in the demos, should count to be fair. Probably nobody cares, but back then it was so cool :)

@Hicks (http://www.cpcwiki.eu/forum/index.php?action=profile;u=581), thanks for doing the interviews, it's a pleasure to read.
Title: Re: History of Amstrad CPC Demomaking
Post by: toms on 21:08, 18 September 18
No need to go back 25 years (30, actually) to find people screeching to get recognized as being the first to do this or that—see for example http://www.pouet.net/prod.php?which=61177  ;D  (http://www.pouet.net/prod.php?which=61177)

Actually Still Rising was finished in 1987 but before releasing it, Hicks asked me to translate the scroll text to english. Because of my lazyness, it was finally officially released in 2013...
Title: Re: History of Amstrad CPC Demomaking
Post by: Hicks on 21:43, 23 September 18
@Duke (http://www.cpcwiki.eu/forum/index.php?action=profile;u=1624): Thanks for your feedback  ;) I'm sorry for french only interview but we are still searching for a translator...

It's usefull to make serious history about CPC demoscene because fake informations are frequents. For example, Longshot claim himself on Demozoo that Amazing Demo (https://demozoo.org/productions/167934/) has been released in September 1989 instead of the real date, December 1989 or January 1990. See for example:
- the first screen of this page: http://cpc-power.com/index.php?page=detail&num=7668 (developped from October to December 1989)
- this interview: https://cpcrulez.fr/demosceneIN_logon_system.htm (Amazing wasn't finished in December 1989)
- this page: http://cpc-power.com/index.php?page=detail&onglet=dumps&num=7668 (Longshot himself wrote a message on the Amazing disk, dated from the 10.01.1990).

The same fake dates on Logon Demo 1 and 2: it's not march 1988 but december 1988 (https://demozoo.org/groups/46351)
The most comical thing is that Longshot was the one who accuse NWC to cheat his release dates  :) :) :)
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 00:09, 19 October 19
I do not know "blink soft demo 3" ; I'll watch this week end too
it seems to be available there http://cpcrulez.fr/demostestDO_blinksoft-demo_3.htm (http://cpcrulez.fr/demostestDO_blinksoft-demo_3.htm)

BSC could be able to find the date

Blinksoft-Demo 3 was released in 1983, I guess. Just a bit after Blinksoft-Demo 1 and 2, which were from 81 and 82, respectively.

Joking aside, I guess it is a relatively young demo, at least from 1990 I suppose. I didn't know Mickey much earlier than that.
I am pretty sure that NWCs demos were among the earliest showing raster bars.
Has this project died btw? That would actually be really sad...
Title: Re: History of Amstrad CPC Demomaking
Post by: Hicks on 10:08, 28 October 19
Has this project died btw? That would actually be really sad...
This project is still on the road, but I need time to finish the first volume (text is 90% completed)!

For everyone: we are talking about a 2 volumes book related to the history of the Amstrad demoscene:
- Volume 1: 1984-1997 period,
- Volume 2: 1998-today period.
If someone is interested here, you can write me a mail at hicks.vanity (at) gmail.com or leave a message on this thread. It could be a kind of "precommand", even if I will probably launch a kickstarter about this soon. I'm planning to publish a french & english version (specify which one interests you).
Title: Re: History of Amstrad CPC Demomaking
Post by: TMR on 10:53, 28 October 19
For everyone: we are talking about a 2 volumes book related to the history of the Amstrad demoscene:
- Volume 1: 1984-1997 period,
- Volume 2: 1998-today period.
Just randomly wandering in and being nosey, but... I was just wondering if the split at 1997/1998 is arbitrary because it needed to happen somewhere or if something specific happened to the scene on the Amstrad at that point?
Title: Re: History of Amstrad CPC Demomaking
Post by: robcfg on 11:03, 28 October 19
I think it’s really a nice project so I’m in for the english version of it.0
Title: Re: History of Amstrad CPC Demomaking
Post by: Duke on 19:57, 28 October 19
Yes, please english version  8)
Title: Re: History of Amstrad CPC Demomaking
Post by: villain on 20:37, 28 October 19
Je prends la version anglaise. Merci! 8)
Title: Re: History of Amstrad CPC Demomaking
Post by: SRS on 21:14, 29 October 19
How about a german version ? most native speakers in the EU and english will vanish from the world on oktober 31th 2019  8)
Title: Re: History of Amstrad CPC Demomaking
Post by: TotO on 21:36, 29 October 19
How about a german version ? most native speakers in the EU and english will vanish from the world on oktober 31th 2019  8)
You will have to learn french next. :o
Title: Re: History of Amstrad CPC Demomaking
Post by: SRS on 21:36, 30 October 19
You will have to learn french next. :o
I did long ago  ... or do you mean the language ?

I prefer the ....
Spoiler: show
cuisine :p
Title: Re: History of Amstrad CPC Demomaking
Post by: Hicks on 12:12, 31 October 19
Thanks for your answers! Then I add robcfg, Duke & villain for the english version. Somebody else?

Just randomly wandering in and being nosey, but... I was just wondering if the split at 1997/1998 is arbitrary because it needed to happen somewhere or if something specific happened to the scene on the Amstrad at that point?
I couldn't do a single volume because it would have been too big. So I decided to but in 1997/1998 for some reasons:
How about a german version ? most native speakers in the EU and english will vanish from the world on oktober 31th 2019  8)
Hehe, the German scene deserve it... Aber willst du das wirklich mit meinem deutschniveau lesen?? :)
Title: Re: History of Amstrad CPC Demomaking
Post by: villain on 14:03, 31 October 19
Hehe, the German scene deserve it... Aber willst du das wirklich mit meinem deutschniveau lesen?? :)
If you are prepared to provide the original text one could look if a translation is doable. Of course so far I have no idea how much work it will be. Probably some Gerrmans would need to collaborate to do this job. But I would not expect a really high demand for the german version. Except some guys from the good old days wake up...
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 13:36, 01 November 19
This project is still on the road, but I need time to finish the first volume (text is 90% completed)!

For everyone: we are talking about a 2 volumes book related to the history of the Amstrad demoscene:
- Volume 1: 1984-1997 period,
- Volume 2: 1998-today period.
If someone is interested here, you can write me a mail at hicks.vanity (at) gmail.com or leave a message on this thread. It could be a kind of "precommand", even if I will probably launch a kickstarter about this soon. I'm planning to publish a french & english version (specify which one interests you).


Good to hear! And - I think I have to point this rather explicitly - PLEASE (PLEASE!) start with an english version. Your english is good enough (most of us are not native speakers anyway) and if you need polishing, I am pretty sure you would find someone proficient to help you with that. PLEASE (PLEASE!) do NOT start with a french version. I don't mean to
say that this could not be a translation option, but english is the lingua franca ( ;D ) of the internet. Nothing else.
Title: Re: History of Amstrad CPC Demomaking
Post by: BSC on 13:39, 01 November 19
Actually Still Rising was finished in 1987 but before releasing it, Hicks asked me to translate the scroll text to english. Because of my lazyness, it was finally officially released in 2013...


Yeah, and I was always mad at how audaciously you stole most of the effects of BSC Demo 0, which was released in the 60s. Shame on you!
Title: Re: History of Amstrad CPC Demomaking
Post by: TMR on 15:11, 01 November 19
Thanks for your answers! Then I add robcfg, Duke & villain for the english version. Somebody else?
I couldn't do a single volume because it would have been too big. So I decided to but in 1997/1998 for some reasons:
  • allow to give 2 volumes with about the same number of pages,
  • around this period, a real renewal of the sceners has occurred (Overlanders, Arkos, DBT & cie become more and more important... and the German demoscene started to disappear after Wizzcat, Exodus, Symbiosis & HJT!)... ok Symbiosis is still alive (Hi Prodatron), but not the demo section!
  • I discovered and been involved in the scene around this period, then I will be helped by my direct experience for the second volume.
Cool, thanks for answering.
Title: Re: History of Amstrad CPC Demomaking
Post by: Gryzor on 14:24, 14 November 19
Just sent an email for an English set.*

Looking forward to this. Just please, please consider avoidint the pitfalls of way too many money-grabbing retro-related projects: cheap production (paper, binding...) and lack of editing! Not that I have reasons to believe you wouldn't, it's just that we don't see too many CPC-related books, it'd be a shame not to have something nice, even if it costs more!


*interestingly, pasting "hicks.vanity (at) gmail.com" into the To: field in Gmail turns it into a normal email address!