Has anyone ever thought of retro fitting an Amstrad with Hardware scrolling?

[Puresox]

This is probably in the wrong place , but heyho , Administrators feel free to put in the right area.
I was having a think about Hardware scrolling and wondered whether it was an expensive thing to add to a machine ,back in the early 80's. I think had the Amstrad been given proper hardware scrolling (To the level of the c64) it would have been a better machine or on par with the C64(Mind you it has the Sid chip too, so maybe not). Obviously it must have been an expense that Amstrad could not make competitively. If anyone on here has understanding of this could explain , that would be great. Anyway whilst thinking about it I wondered whether anyone had thought about making it available on say an emulator , so that  games could be programmed utilising this feature ? Or is this Sacrilegious and a ridiculous suggestion , that shall remain merely a dream?? Oh and I know the Plus range has hardware scrolling doesn't it? But is really isn't in the same league as the C64 is it?

[arnoldemu]

This is probably in the wrong place , but heyho , Administrators feel free to put in the right area.
I was having a think about Hardware scrolling and wondered whether it was an expensive thing to add to a machine ,back in the early 80's. I think had the Amstrad been given proper hardware scrolling (To the level of the c64) it would have been a better machine or on par with the C64(Mind you it has the Sid chip too, so maybe not). Obviously it must have been an expense that Amstrad could not make competitively. If anyone on here has understanding of this could explain , that would be great. Anyway whilst thinking about it I wondered whether anyone had thought about making it available on say an emulator , so that  games could be programmed utilising this feature ? Or is this Sacrilegious and a ridiculous suggestion , that shall remain merely a dream?? Oh and I know the Plus range has hardware scrolling doesn't it? But is really isn't in the same league as the C64 is it?

to make it work correctly you would need to delay x number of pixels, and you would need potentially 2 bytes more of storage which you could shift into.
Gate-Array already has 2 bytes storage, so another 2 may have taken it over the gate-count that they could have had at the time???

If it was added to an emu, the emu is no longer emulating a true cpc.

In addition if it was added to existing games, they now play a little different because the scrolling is a different speed.

Enjoy the Plus which has soft scroll.

[arnoldemu]

to make it work correctly you would need to delay x number of pixels, and you would need potentially 2 bytes more of storage which you could shift into.
Gate-Array already has 2 bytes storage, so another 2 may have taken it over the gate-count that they could have had at the time???

If it was added to an emu, the emu is no longer emulating a true cpc.

In addition if it was added to existing games, they now play a little different because the scrolling is a different speed.

Enjoy the Plus which has soft scroll.

EDITs:

The CRTC tells the Gate-Array which pixels to read. Gate-Array reads 2 bytes and stores them internally, then it sends these out to the tv/monitor.

In order to do pixel scroll it needs to delay by x pixels (x where you program it). To do this it now needs more than 2 bytes, and it needs a register to define the scroll value. Both of these take silicon.

It's not known if they reached the limit of gates in the gate-array or not.

So potentially it could have been more expensive to do because of the extra gates required.

I wish they had considered it though.

[EgoTrip]

I don't see the point personally. If you want a computer to behave like another computer, then you might as well just use the other computer. The CPC can do a decent enough job of scrolling when done right anyway and the fact it uses software to achieve it shows what a decent machine it really is.

[MacDeath]

the CPC can scroll better than MSX1&2...


Also what you are asking for does exist, it is called the Amstrad PLUS...




Anyway I think Hardsprites would be more interesting than scrolling.

[TFM]

The CPC has proper hardware scrolling. Examples are Relentless, Tornado Low Level, Mission Genocide and others.


The problem is that game companies forced coders to do dirty speccy ports instead of doing a proper rewrite for the CPC.[nb]If you got 3 weeks then you can't do much in that time.  [/nb]

[MacDeath]

One thing i'm thinking about at the moment, but not sure it can be possible : some card that would enable to use 2 amstrad on the same screen at the same time.

One would be overlayed on the other (one of it's ink being transparancy then) thx to some video incrustation device.

Both machines would be connected and somewhat synchronised so sounds and video would be mixed.

as a result one of the CPC would be used for background, the other for foreground, meaning some sort or sprite layer.

This would constitute a "machine" or system closer to some arcade systems, with 2x Z80, background and foreground, 2x AY sound and so on... would have like 256K RAM in case you get 2x6128... but a 464 could really suffice as secondary machine.


As each CPC/PLUS would only manage one layer, less need to mask spries or whatever... you be sure they are well synchronised and the video is well aligned on the same screen.
Could even be fun to program or to design games/graphics for...

Imagine Mode1 in 4+3 inks... (plus rasters)
Or 2x Amstrad 6128 PLUS would make quite a nice system indeed..

The good point with such a method is that you don't really modify the original system/computers, you just cumulate 2 machines in one...
The card would just be a mixer for both Video and Sound, and would just link the Amstrads together (like some Memory handshake, common timer/clock or network...).

The rest would just need a good programation and mastering of timers on both machines I guess.

[Puresox]

Amstrad Hardware scrolling was a little on the fast side , Relentless and Mission Genocide are probably the best examples of good scrolling on the Amstrad , it amazes me that more wasn't done with the Technique used by Mission Genocide?

[andycadley]

Oh and I know the Plus range has hardware scrolling doesn't it? But is really isn't in the same league as the C64 is it?

The only nice thing about the C64 over the plus is that it's display is character based rather than a straight bitmap, which allows for a lot of clever little effects. In every other respect it's really not even near to the same league as the Plus range from a graphical perspective. It's still a real shame that people haven't tried making more of the range.

If you were to try and retro-fit hardware scrolling onto the CPC, you'd do it in the way Arnoldemu describes which, oddly enough, is basically what the Plus hardware is doing. So why emulate a fake machine when the real thing exists?

[Puresox]

I am not technically minded in a computer sense , So I am speaking from just a gamers perspective  And I have to say that I have not seen scrolling as good on a plus machine as I have seen on a C64 . But I am not going to argue the point as this is all hypothetical. It was just a musing I had. And wondered whether I could find out a reason why it wasn't implemented to a greater extent on the original machine. Obviously it must have been down to cost  , I do not know how or what technology gives the C64  it and the CPC not. Appreciate your inputs though( although It is difficult for me to totally understand , some of it makes sense )

[MacDeath]

Amstrad Hardware scrolling was a little on the fast side , Relentless and Mission Genocide are probably the best examples of good scrolling on the Amstrad , it amazes me that more wasn't done with the Technique used by Mission Genocide?

First I think Vertical and Horizontal are two very different things.

And quite some games managed to show CPC can somewhat scroll well.
But I guess to use a 128K CPC can greatly help, just because it eases for some RAM intensive tricks : double buffering, tileset with a pixl shift and so on...

isn't vertical scrolling easier ?

And I have to say that I have not seen scrolling as good on a plus machine as I have seen on a C64 .

Saddly the PLUS never got decent specific horizontal shooters, nor even vertical ones...


let's see :
=Mistycal : a straight disk to cartridge CPC port.


=Copter 271 : an unfinished game with lot of design flaws to begin with.
128K onlycartridge, and unfinished, uses a horizontal scrolling that only plague the game (which is a vertical scroller actually), too heavy use of the hardsprites, annoying palette and noise...


that's all that can be considered " 2D shooters" and both are vertical.


Robocop has a sweet multidirectionnal scrolling indeed.

[Axelay]

It was just a musing I had. And wondered whether I could find out a reason why it wasn't implemented to a greater extent on the original machine. Obviously it must have been down to cost

If you look at the simple kinds of games that were appearing on the home computers in the very early 80's, even on the C64, then scrolling games don't seem to be very common, so per pixel scrolling may just not have seemed important at the time they were designing the CPC.


I'm not convinced per pixel hardware scrolling made easy on the CPC would have changed very much though.  Consider how many spectrum ports were modified only so far as to get a spectrum game running on the CPC, with little or no alterations or optimisations to make better use of even the CPC464, let alone later CPC models.  There's also the parallel on the Amiga where despite having hardware scrolling and a blitter, many games were clearly not running as well as others, making them reasonably obvious ST ports that had made no use of the Amiga hardware except where they had no choice but to change things.  So I dont think much would have changed if the CPC had possessed easy per pixel hardware scrolling, because it would have required far too much rewriting of the spectrum code base most developers were starting from to take advantage of it.  Though I gather French CPC games were not usually ports from anything, so they may have ended up an exception.

[AMSDOS]

If it was added to an emu, the emu is no longer emulating a true cpc.

I would agree that a real CPC would have to demonstrate this scrolling, it's bad enough that an emulator can run beyond the 4Mhz limit.   

[Puresox]

Actually I take it back , The scrolling on Navy Seals is pretty good . And just as good as C64's .

[TotO]

Because it use the PLUS hardware scroll.

[AMSDOS]

Actually I take it back , The scrolling on Navy Seals is pretty good . And just as good as C64's .

I know people frown at "Green Beret" if that game is similar to "Navy Seals", personally I'm one of the few (if not the only one) that isn't bugged by the scrolling in GB, though I guess it could be a bit crude for the time period it came out in.

[arnoldemu]

@Axelay, I would love to see what game you would make if you used CPC smooth vertical scrolling.

Do you have some code that can do it? I can provide some if you need some

[Xifos]

I once asked Axelay to do a vertical shooter, but he said no !


Maybe i'm wrong, i asked Fano...



But the answer was : do it yourself !!


It's true that a shooter with vertical hardware scrolling using two screens and CRTC reg 5 would be great !

[TotO]

I once asked Axelay to do a vertical shooter, but he said no !
Maybe i'm wrong, i asked Fano... But the answer was : do it yourself !!

They are greats! 

[sigh]

Bullet Hell!


It would be nice to see something "Cave" shooter like on the CPC., with it's vertical scrolling.

[TotO]

Don't dream... Cave games "like" are maniac shooters with tons of bullets.
The CPC is not the good hardware for that.

But, nice 80's hard vertical scrolling games can be done w/o problem.
Just do it... Because, more peoples done things on CPC and more the computer will stay alive.

[dragon]

EDITs:

The CRTC tells the Gate-Array which pixels to read. Gate-Array reads 2 bytes and stores them internally, then it sends these out to the tv/monitor.

In order to do pixel scroll it needs to delay by x pixels (x where you program it). To do this it now needs more than 2 bytes, and it needs a register to define the scroll value. Both of these take silicon.

It's not known if they reached the limit of gates in the gate-array or not.

So potentially it could have been more expensive to do because of the extra gates required.

I wish they had considered it though.

well, commodore, desing and manufacture their own chips. They can desing 1000k or 2000k gate array with the only limit of their manufacture tecnology. Amstrad needs subcontract it to ferranti. So they are limited to ferranti products capacity. Original Gate array is based in 5000R series ula with 2000 gates max capacity.

Ferranti have 4000 and 10000 gates model, but ther appeared later in market ,In the begining 2000 gates are the maximal offecered, so depend on ferranty 4000 gates time and time cpc development. Mayme amstrad is limited  to 2000 gates or, maybe is limited to gate array cost or heat cost.

[Munchausen]

Well it would be great to add more features, and though it's a lot of work we can dream right? (what a christmas present that would be!).


I guess you'd need to reimplement the gate array and add more features. Maybe a small FPGA in DIP format (like this http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,798&Prod=CMOD) but you'd need to add 5V and the correct pinout. Or a 40 pin PLD/CPLD (I found the Atmel ATF2500C), but I guess it might need some pinout adapter or something.


Of course, finding the hardware is easy... making it work is something else completely.

[TFM]

Don't dream... Cave games "like" are maniac shooters with tons of bullets.
The CPC is not the good hardware for that.

Do you talk about Shumps? I guess I miss the point somehow. Do you have a youtube link for an example?

[TotO]

Cave games are maniac shooter only. You can type "CAVE shooters" in youtube to die.
Here, one of them to understand:


DoDonPachi DaiFukkatsu Black Label Zatsuza [high quality]


No, it's definitively not possible to do that on CPC!