Atari ST games with smooth scrolling - how?

[Marce]

Originally Posted by SyX

And if you want to see cpc games making use of the hardware scroll, you can take a look to games as Prohibition by Infogrames or Skateball by Titus, for example. But it is very important to see those games in a CPC using a CRT, you will not feel smooth by looking them in youtube videos.

1: I don't look at youtube videos to test a game, to test amstrad CPC games I'm using the best amstrad cpc emulator for windows which is CPCE

2: Prohibition cpc version is not scrolling , you are confused as other members,Prohibition is pushing the screen or is jumping when the screen reach certain point,

3: Prohibition is the port of the arcade "Empirecity 1931" run the game on Mame and you will learn what is scrolling

4- the amstrad cpc not have any hardware scrolling, is a myth invented here or somewhere else

[SyX]

Originally Posted by Marce

1: I don't look at youtube videos to test a game, to test amstrad CPC games I'm using the best amstrad cpc emulator for windows which is CPCE

Wrong answer!

If you know anything about the CPC, you would know about the CRTC Compendium, the last test bench for the CRTC and you would know that CPCE doesn't pass those tests. Then maybe you should be watching youtube videos...

Second thing, if you are using an LCD screen in your windows machine, then sorry, but I need to tell you that scrollers are not smooth at all. Specially neither in CPC or any other PAL system.

Originally Posted by Marce

2: Prohibition cpc version is not scrolling , you are confused as other members,Prohibition is pushing the screen or is jumping when the screen reach certain point,

I think that you are the confused one, push scrolling is only a game design technique, it continues to be an scrolling, yes or yes.

Now, let me explain to you how scroll hardware works in the most simple way and in any system, not only the cpc. Scroll hardware is when you change the hardware registers that control where the screen memory starts, making possible that you don't need to shift the video memory using the cpu. I can explain you about coarse and smooth scroll, if you want all the details.

In the CPC the registers 12 and 13 in the CRTC chip control exactly that; because Prohibition uses those two CRTC registers, then Prohibition is doing scroll hardware in the CPC. Ikari Warrios is not doing that, then the scroll in IW is only software.

Originally Posted by Marce

3: Prohibition is the port of the arcade "Empirecity 1931" run the game on Mame and you will learn what is scrolling

Yes, I know that game, even my grandparents know that game. But that is doesn't change that the developers have the choice of using continuous scroll or using push scroll. The arcade guys did continuous, the Infogrames guys prefered to use push one.

Originally Posted by Marce

4- the amstrad cpc not have any hardware scrolling, is a myth invented here or somewhere else

We live in the era of Fake News, then this is not news and is not true.

Amstrad CPC has scroll hardware, for starting the Basic interpreter uses scroll hardware. The two first CPC games, Fred/Roland in the Caves and La Pulga/Poogaboo use scroll hardware. And I could list a hundred of CPC games from the commercial era that used scroll hardware in the CPC, but I doubt that you are going to open your eyes to the truth, then I am going to save my fingers.

Funny thing is that a lot of those games are CPC exclusives, maybe you can start to understand that the games, that made a better use of the platform, were developed using the strong points of the CPC; and the CRTC with its hardware scroll is one of them. And the reason for all those great CPC games using scroll hardware during the homebrew era.

Another funny thing is that you choose only speak about Prohibition because is using "push" scroll and is good for your "master class" about how the cpc is shit doing scrollers; but you forgot to speak about the other game, a game that is using smooth horizontal hardware scroll, exactly the thing that you said before that it was impossible in the CPC.

I can do the same, I can choose any system and I will find an argument so stupid that let me show how that system is better or worst that any other one... but that is useful for what exactly. How about a nice game of chess?

[hitchhikr]

Second thing, if you are using an LCD screen in your windows machine, then sorry, but I need to tell you that scrollers are not smooth at all. Specially neither in CPC or any other PAL system.

Actually newer LCD screens and newer PC gfx cards handle 50hz via DVI-D input/output with 720p/1080p resolutions (not PAL but still looks smooth emulating PAL machines).

[roondar]

Originally Posted by hitchhikr

Actually newer LCD screens and newer PC gfx cards handle 50hz via DVI-D input/output with 720p/1080p resolutions (not PAL but still looks smooth emulating PAL machines).

This is true, though I still sometimes see some visible jitter that I don't see on my CRT when a dual layered screen has the background layer scroll at 1/2 frame rate. Foreground scollr @50Hz can be done very smoothly these days though, if your monitor supports either 50 or 100Hz

Perhaps OLED improves this BG jitter I sometimes see, I dunno.

[SyX]

Originally Posted by hitchhikr

Actually newer LCD screens and newer PC gfx cards handle 50hz via DVI-D input/output with 720p/1080p resolutions (not PAL but still looks smooth emulating PAL machines).

Sure, but good luck trying to explain about how gsync/freesync works to a guy that can't or doesn't want to understand how hardware scroll works and can not see the difference between hardware and soft scroll.

[Longshot]

Hello.
Is an amiga able to do such scrolling? :-)
[ Show youtube player ]

[TCD]

There should be a massive epilepsy warning...

[gimbal]

Originally Posted by TCD

There should be a massive epilepsy warning...

Or just a head ache warning in any other case. That video is not good for you. Ouch.

[S0ulA55a551n]

Originally Posted by TCD

There should be a massive epilepsy warning...

In flashing lights ?

[rothers]

Originally Posted by Longshot

Hello.
Is an amiga able to do such scrolling? :-)
[ Show youtube player ]

Don't forget this is fake news

[lmimmfn]

Originally Posted by TCD

There should be a massive epilepsy warning...

Don't shoot the messenger, I agree the video is rough(not synced with PAL signal) but the result is impressive for such an old computer, remember the CPC came with a monitor so the ability of the hardware can only be seen on a real CPC while the emulators catch up which has been documented here
https://shaker.logonsystem.fr/
And also the latest Compendium in english is available here http://logonsystem.fr/html/downloadlogon.htm

Question, I know with AGA the Amiga has sub pixel scrolling 1/4th of a pixel but does it have sub pixel vertical? (Without DBLPAL/interlace etc)

[Photon]

Originally Posted by Retro1234

Smooth scrolling - How was this done on the ST looking at "Back to the future 2" (not 3 !!!) and I know I've seen a few other games. There full screen no vertical border score thing on screen.

Turricun
CarVup

Basically how on a standard ST without any hardware scrolling?

In the early days only vertical, about 8? years ago sync tricks only on PAL I believe, horizontal is the tricky part done with buffers. You sort of have to choose direction if there is no way of delayed sync or similar, it's really difficult to do 8-way if the platform provides no way. Maybe if you put big memory requirements and the big deal is showing off the scroll capability and less about gameplay.

On 8-bit non C-64 this was done the same way except e.g. on MSX some cartridges included a simple "blitter" or copy chip which helped, but not good enough for action graphics just for non full framerate text scrollers and similar.

[ImmortalA1000]

The VIC-II had sub-pixel horizontal scrolling [in multicolor modes] already.

I've used my Amigas on my Plasma TV via SCART RGB and it is brilliant, no weird compression artefacting or anything and plasma is the only screen that comes close to CRT look. I was playing Lotus II on my 60 inch TV lol brilliant.

There is a Youtube channel with a guy from Traveller's Tales, coding secrets I think, and perhaps somebody could ask him nicely how they did the 8 way smooth scrolling engine for Leander on the Atari ST. Very impressive as it looks like a pixel scroll....which is technically impossible for the 512k ST (possible with about 2.5mb I think).

[gimbal]

Didn't he already do a video on it?

No, that was on doing a lot of sprites on the Amiga version. The existence of that video should at least be an indicator that he'd be willing to spill the beans on it, assuming he actually did the ST version.

[ Show youtube player ]

Last upload was 11 months ago though, so it looks like the channel is asleep currently.

[Megalomaniac]

2Mb of memory just for the graphics to smoothly scroll in 8 directions on an ordinary ST sounds about right, if Anarchy needed to use up 256k to smoothly scroll in one direction. Maybe there's more data duplication than we realise when looking at it? The backdrops are pretty simple on ST Leander, which probably helps. It does look better on the Amiga, and being by Psygnosis the gameplay doesn't live up to the audiovisual side, but it's still quite something. Contrast it with the utterly unplayable ST Robocod from the same time (by a much more experienced ST coder) to see the difference that can be made.

[Galahad/FLT]

Originally Posted by gimbal

Didn't he already do a video on it?

No, that was on doing a lot of sprites on the Amiga version. The existence of that video should at least be an indicator that he'd be willing to spill the beans on it, assuming he actually did the ST version.

[ Show youtube player ]

Last upload was 11 months ago though, so it looks like the channel is asleep currently.

Leander on the ST hd nothing to do with Jon Burton, it was a WJS Design conversion.

As with most Psygnosis stuff, if a game lead on Amiga and really used it, rarely were the developers of the Amiga version expected to do the ST version.

[gimbal]

Right. That probably explains why there is no such video on the channel already

[Megalomaniac]

As early as Menace, most Psygnosis games looked and sounded noticeably better on the Amiga. Having just checked out the ST and Amiga versions back-to-back (in that order) the ST has a monochrome player sprite, weedy sound effects, a smaller play window and (less importantly) a laughable starfield effect on the intro. It's still pretty reasonable by ST standards for that time though, it's not another Shadow of the Beast where the ST version made no effort to exploit what the system could do.

[ImmortalA1000]

Wrath of the Demon on the ST is a good idea how Shadow of the Beast could have been but you have to remember Beast is a game engine born of the toy box that is the OCS chipset features. Sure it could have been better but it's a bit like Rescue on Fractalus on the C64 being done by a better coder than the author of something as basic as Shamus, it was always designed around the advantages/limitations of the Atari 800 by the god of fractal coding, Loren Carpenter.

The ST as I understand it has a screen registry pointer that requires two bytes, if you want to scroll horizontally in less than 16 pixel jumps you need to allocate duplicate 32k screens with preshifted tiles for however many pixels you really want to scroll.

The ST was nothing more than a 16bit version of something like the Amstrad CPC or Acorn BBC computers so if you are not coming from an Atari 800 or C64 or you were buying your first computer in 1987 for £299.99 it was absolutely good enough. Still, as someone who had a C64 in the early days, a VCS before that since 1980 (before Space Invaders was released), and played Atari 800 games almost on a daily basis. I thought my ST in 1986 was OK for some types of games. Road Runner on the ST vs the C64 is a good comparison of what you would gain/lose if you opted for a £249.99 C64+tape deck bundle instead of a 520STFM for £299.99 as it's a horizontal scrolling multi-load game. YM2149 of the ST was the biggest 'mistake' as with most systems with reasonably fast screen memory you could do reasonable software scrolling with enough talent IMO. 'enough talent' is the key word here.

[S0ulA55a551n]

Originally Posted by rothers

Don't forget this is fake news