SonicGX (Sonic homebrew for Amstrad GX4000)

Just ran into this today and didn't notice any threads on it -

https://www.youtube.com/watch?v=WStLxy-Zacg

Looks like they intend to port the whole Master System game to it and release it by the end of the year.

The game looks kind of cool, definitely the most impressive thing I've seen running on the console, but even so it really cements that the system was under-powered. I mean, this console was released two years after the Mega Drive and the same year as SNES but they're going for enhanced Master System/Game Gear ports, that tells you a lot to be honest.

The low resolution (one of the console's biggest weaknesses) actually doesn't look too bad here though surprisingly, I think the high-ish colour counts help to mask it somewhat. The game looks pretty smooth as well, which is nice.

There was also a homebrew port of Ghosts N' Goblins released a few years back

https://www.youtube.com/watch?v=uhZCmrDL4pY&t=96s

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The GX4000 was a British console released in 1990 by a company called Amstrad, who had success in Europe selling Home computers prior to trying to enter the console market. Its often considered one of the worst consoles ever made and had very little commercial software made for it.

https://i.ibb.co/YDg11d3/index.jpg

It's nice to see some attempts to show what the console is capable of.

Yeah whoever came up with the GX4000 at Amstrad must have been shoving mushrooms up their nose. A console that can't even be called better than the master system (lower resolution) in 1990 was never going to be successful...

That looks really nice, the high colour count really does lend it a shade more polish. Cool.

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Looks like they intend to port the whole Master System game to it and release it by the end of the year.

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It looks like a GG game more.

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Originally Posted by Kamahl

Yeah whoever came up with the GX4000 at Amstrad must have been shoving mushrooms up their nose. A console that can't even be called better than the master system (lower resolution) in 1990 was never going to be successful...

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Sure it kind of sucks for the release year, but I don't think its fair to compare it unfavourably to the Master System, I mean, yeah the resolution is way too low, but like I said the larger master palette helps to mask this as they can blend the colours together better so that its less noticeable. Master System is higher resolution but the colours clash with each other more (GX4000 is also near full screen unlike the SMS, which is bordered)

https://i.ibb.co/bFcKF2V/fdghdhf.png

Actually, its more comparable to a full-screen Game Gear console in some ways due to the resolution and master palette difference.

I can't remember much of the GX4000 details that we all talked about years ago on here anymore, but IIRC there were 16 16X16 pixel, high resolution sprites per line? (twice the width and, twice the number of SMS sprites per line) and you could expand them X2, simply doubling up the pixels.

Well as soon as you give up and go with the low resolution mode, you'd might as well use X2 magnification on all of the sprites as well to bring them into consistency with the background resolution. Unless I'm misunderstanding something, at that stage your sprites are absolutely huge in comparison to the normal Master System sprites and match the background resolution, which greatly lessens the GX4000's problem with sprite multiplexing (in regards to 3rd gen, 4th gen is a lost cause).

Sound was just outright better on GX4000.

Either way the GX4000 was considerably better than your beloved Amstrad CPC6128 Kamahl, a £300 overpriced dog with a mandatory monochrome monitor unless you wanted to pay even more! at least the GX4000 was cheap :D

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Originally Posted by Thenewguy

Either way the GX4000 was considerably better than your beloved Amstrad CPC6128 Kamahl, a £300 overpriced dog with a mandatory monochrome monitor, at least the GX4000 was cheap :D

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Beloved? Bit of a strong word there, I do like the homebrew scene of the CPC but the machine itself is really uninteresting.

The GX4000 (and the CPC+ line) is weird in that it has 4th gen console tier sprites per line, but would really struggle to multiplex them so it ends up being closer to 3rd gen sprite numbers.
The X2 magnification is the way to go for low res games.

It might be possible to pull off a stylish high resolution game with some work though, I mean, the Atari 800 can do pretty looking things with 5 colors per line, and that's in low res with only 256 colors for a master palette. But for 1990? That's after the Amiga, Lynx, PC Engine, Mega Drive and SNES. Outdated is an understatement.

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Originally Posted by Kamahl

Beloved? Bit of a strong word there, I do like the homebrew scene of the CPC but the machine itself is really uninteresting.

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Seeing SonicGX makes me somewhat interested in the GX4000 homebrew scene.

Given that it was a UK console I'd kind of like to see someone port Robocod to it, with the gradient backgrounds and everything. That game appeared on most consoles of the time so it definitely would've ended up on GX4000 if it had been successful here, I also don't think its out of the GX4000's capabilities, heh.

I have a little interest in the CPC464 homebrew, there's a racing game in development that looks pretty unbelievable.

No interest in 128k Amstrad machines, crappy things they were.

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Originally Posted by Kamahl

It might be possible to pull off a stylish high resolution game with some work though, I mean, the Atari 800 can do pretty looking things with 5 colors per line, and that's in low res with only 256 colors for a master palette.

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Yeah I remember the conversations, heh, I think I made a mock-up of Mario World and Magical Chase? the pictures don't exist any more.

I still have the picture of Spectrum Arkanoid though, I considered making a demo of it in Spectrum Arcade Game Designer.

Right, now I remember, the Magical Chase one looked really good!

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Originally Posted by Kamahl

Yeah whoever came up with the GX4000 at Amstrad must have been shoving mushrooms up their nose. A console that can't even be called better than the master system (lower resolution) in 1990 was never going to be successful...

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"Our computer hardware division is falling apart and we need to do something to stay relevant."

I mean, it seems to be the common pattern for all those consoles from that time based on computers.

I only heard of this thing on forums within the last decade. Had no idea it's specs were that low. Tho fan projects like this are cool. So I know very little about British electronics and computers. I know of Amstrad through the Ashens channel. In some British shows, they joke how made in Brittain means bad(not always electronics tho). Were UK electronics really poor quality? Not trying to throw flames. Just honestly curious.

Amstrad was and still is a company that mostly release one time of gadget products often based on somebody elses design that they just licence. They just say that consoles where on their way up so they thought we can do that to. Commodore did the same thing. Atari also abandone their rather succesfull ( in europe) computer line to focus on consoles. These companies were struggling and tried to find a way out. I like the GX4000 it plays well but sadly most games suck dick. That happens when companies like Ocean are your main provider of games :D.

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Originally Posted by Sik

"Our computer hardware division is falling apart and we need to do something to stay relevant."

I mean, it seems to be the common pattern for all those consoles from that time based on computers.

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You've also got to remember that the PC-Engine was never properly released in Britain, and the Mega Drive wasn't released here until Autumn of 1990. These guys were likely completely out of the loop I think, they were making something to compete with a resurgent 8-bit console market, primarily aiming to take on the Sega Master System which was about to have its second wind in Britain as a budget machine.

Had it come out a year earlier it might have had a chance in Europe I think (and only in Europe), but they also would've needed to actually invest money in software development, just re-releasing Amstrad CPC games is unacceptable and makes the system look very inferior to the NES and SMS.

Of course had the PC-Engine had a proper nationwide release in the UK in the late 80s it likely would've dominated, so any chance of success the GX4000 really could've had was down to their competitors screwing up in the beginning anyway.

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Originally Posted by Leynos

In some British shows, they joke how made in Britain means bad (not always electronics tho). Were UK electronics really poor quality? Not trying to throw flames. Just honestly curious.

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The cars were bad, especially in the 1970s. Marxism really screwed up post-war Britain, but that was coming to an end in the 1980s.

The computers were pretty cool, maybe not as fancy as some of the big US computers, but they have their own quirks and often represented great value for money IMO.

The consoles not so great, other than the GX4000 was the Atari Jaguar actually which was made here, heh, I've heard there was a lot of promise with that hardware but that Atari forced the designers to release it unfinished or something. Getting companies to develop software for the thing was pretty hard too, given that Atari's name was largely just associated with out of date hardware by that stage.

Not really familiar with much else really, Britain hasn't made a whole lot of electronics goods for a long time now, there are the Dyson vacuum cleaners, which I've heard people rubbish online somewhat, but my family have never had any trouble with them and my parents used to talk about them in high esteem (as high an esteem as someone can manage for a vacuum cleaner). I think they still have the same one they bought near 20 years ago actually.

The Fact that the British invented the mothafuckin ARM chip range that everybody and his dog uses these days must count for something :D

Also what you guys are missing is pricepoint The GX4000 was released at 99 pounds (with two controllers and a game) the Mega Drive was £189 (with a game and a controller). The reason why a lot of companies like Amstrad and Commodore released console versions of their home computers was to battle the rampant piracy here in europe. However the prices for the cartridges where much higher then tapes or disks. So everybody just stuck with their homecomputers instead of the console versions.

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Originally Posted by highlandcattle

Also what you guys are missing is pricepoint The GX4000 was released at 99 pounds.

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But the Master System was released at that price here as well.... three years earlier. By 1990 the Master System had also had enough time to build up a library of older games that could be sold for cheaper, it was much better positioned as a budget machine.

and as Kamahl said there were still a few hardware trade-offs even!

GX4000 needed to turn up a decent amount of time prior to the British launch of the Mega Drive to have any chance.

Some UK made machines were pretty decent. The ZX spectrum might not be very impressive, but it was dirt cheap.

The Acorn Archimedes actually had some rather impressive hardware. 256 color graphics, 8 channel PCM sound, and a CPU that was over 4x better than the 68000 on the Amiga 500 released at the same time. It lacked the graphics chips of the Amiga but the CPU was so fast you could redraw the whole screen and still have a decent framerate.

I think all the main 8-bit computers were pretty reasonable in their own way, the UK made loads of computers in the early 80s so only the most competitive survived (we also got all the major US computers, as well as the Japanese MSX computers).

Spectrum represented fantastic value for money and was very accessible

Amstrad CPC was a decent all rounder, it was easier for people who wanted a "complete package" to deal with, given that it came with built in tape deck/disk drive, and its own monitor. IIRC it was better than the others at being an actual computer, heh, OS and BASIC were better than Spectrum and C64, it also had a numeric keypad and proper arrow keys. Struggled with action games but for slower paced games there's a lot to be said for having 16 colour graphics even if they're pretty low res.

BBC Micro was the oldest of the main three, was quite fast, robust and expandable IIRC, at the time good OS and BASIC too.

I don't really know anything about the 16-bit UK machines as they never really went anywhere.

The Archimedes was incredible, it's really a shame that it didn't do better than it did (got stuck as a "school machine").
It can do graphics comparable to very high end 386 DOS VGA machines for a fifth of the price (800 pounds back in 1987).

https://www.youtube.com/watch?v=ytyNR9Bo7Es

I had heard about the Archimedes over the years but I didn't realise it had as many games on it as it seems to have had.

I thought it was barely supported.

Argonaut was big on Archimedes before they got on board with Nintendo.

But yeah, I'm not surprised it didn't do that great outside the education market, turns out compatibility was starting to become a problem (by the late '80s most of the focus was starting to go to PC), though the spiritual successor (RiscPC) seems to have gotten some foothold with broadcast stations. Mind, the one place where Archimedes was wildly successful was its CPU (hint: this is where ARM originated).

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Originally Posted by highlandcattle

The Fact that the British invented the mothafuckin ARM chip range that everybody and his dog uses these days must count for something :D

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Brilliant point! Thank you. So maybe it was a joke in general on some things. I also know Ashen has made a few jokes but he does anyway I guess. Tho one old tablet or PDA he had I think was Amstrad (don't quote me on that) the plastic was deteriorating to the point it was toxic to touch so he wore surgical gloves to protect him.

Edit. Here it is. So I guess it wasn't UK electronics, just Amstrad he says was poor quality.
https://www.youtube.com/watch?v=tQ38F9GnDQM

Then the jokes about UK cars and IT Crowds Fire Extinguisher made in the UK joke. I got the impression stuff made in the UK was badly made. I don't deny my ignorance on UK made products. However yo bringing up ARM is a great point as ARM are some of the best in the world. THE best at mobile CPUs

Well, ARM doesn't really make CPUs anymore, they just design the CPU architecture (which is excellent mind you). The best at mobile CPUs are Apple :), whose CPUs are so fast they can beat laptop intel CPUs that require a lot more power and active cooling.

What do you make of this Vespertino project Kamahl? It looks far too good to be true but the people doing it seem to be quite well respected in the Amstrad community due to previous projects like their port of Pinball Dreams.

I take it the car rotation is just done by using piles of memory and will be limited to the cartridge versions, but if the CRTC really can be used to scale a road at little CPU cost on ordinary Amstrad CPCs then this surely would be a game changer for the GX4000 as well, given that it could add its independently coloured sprites on top of that.

https://www.youtube.com/watch?v=YAcd47eUZF4

There is no way they're doing that crazy big car rotation on the non cartridge versions.
Really curious to see how well the main game will run on a 64kb Amstrad running off a floppy disk.

What allowed Pinball Dreams CPC to run as good as it did was it using hardware scrolling.
You can't really use hardware scrolling in Vespertino (at least not for the road, the mountains I'm sure they figured out a way), so I wonder how they made it that fast and smooth.

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Originally Posted by Kamahl

Really curious to see how well the main game will run on a 64kb Amstrad running off a floppy disk.

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I believe the 64k version requires an adapter to plug cartridges into it, the disk is 128k only.

I'm hoping they optimise it for GX4000 but they don't seem fussed about doing that at this stage.

Yeah there was no way they were pulling this off on a standard 64k CPC.
Unfortunate but that's the reality of the machine. You need tons of memory to do stuff, and that means either a cartridge or my "beloved" 128k.
I'm pretty happy that some of the really good homebrew releases (like Operation Alexandra) run on 64k. It's a shame Star Sabre needs 128k to have music but at least it runs on 64k.

What I am not happy about are C64 games still using low resolution graphics. That GX4000 Sonic game looks great because it has 32 colors onscreen out of a huge palette.
The C64's color restrictions on low-res mode are just too much and it makes the games look drab and ugly, only Sam's Journey managed to make them look good and I would still prefer high-res.

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Originally Posted by Kamahl

That GX4000 Sonic game looks great because it has 32 colors onscreen out of a huge palette.

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I think it also works because of how zoomed in everything is, I was thinking of all those Intellivision homebrew ports Black Tiger was posting, and how much worse Castlevania sprites looked than Ninja Odyssey sprites. When you're working with 8-bit sized players and enemies you simply don't have enough pixels to fit in with low resolution to get any level of detail, you can barely fit eyes and a nose into the head let alone ears, eyebrows, mouth etc etc.

When you think about it the low resolution Sonic sprite isn't really any less detailed than the Master System one, all the pixels are there, they're just doubled up, which causes Sonic to look a little more pixelated but not like a lego brick monstrosity. You can see how much the GX4000 graphics suffer when doing 8-bit sprite sizes with the Ghosts N' Goblins homebrew, which looks considerably worse (though the shading does offset the low res a little there too)

So to look reasonable, GX4000 needed to use zoomed in Game Gear style screen layouts, and game's would've had to be full screen other wise there wouldn't be enough space to see where you're going.

It's different with Intellivision, because the sprites are in a higher resolution than the background and can be scaled a bit horizontally and a lot vertically.

Sprites are also built from the same pool of cards/tiles thst the background draws from... but you can use two cards stacked vertically for a single sprite block. So a sprite can pack in much more detail and still be proportionate to the background by stretching/scaling.

Different productions will balance it differently, but ports always suffer from targeting something designed for different hardware. Since cards and sprites are precious, enemies in games with many at once ate usually single color and iften single card per frame.

This what I found mist interesting about GX4000 homebrew. To see how certain bottlenecks/quirks manifest in a game trying to push boundaries.

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Originally Posted by Thenewguy

When you think about it the low resolution Sonic sprite isn't really any less detailed than the Master System one, all the pixels are there, they're just doubled up, which causes Sonic to look a little more pixelated but not like a lego brick monstrosity. You can see how much the GX4000 graphics suffer when doing 8-bit sprite sizes with the Ghosts N' Goblins homebrew, which looks considerably worse (though the shading does offset the low res a little there too)

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I hadn't thought of it but that makes a lot of sense. Same reason why Game Gear and Gameboy games don't look like lego brick monstrosities (I love the description, gonna steal that one).
The amount of detail is the key. It's also why Sam's Journey looks so good despite the low resolution, and some Amstrad and Intellivision homebrew as well, all the pixels are very carefully placed to maximize detail.

This (where you really notice the lack of detail, the few high res tiles only make it more noticeable!):
https://3.bp.blogspot.com/-EW4acZZuI.../soulless2.png

vs this:
https://jefklakscodex.com/img/articles/wario3.png

Yup that's a good example, imagine being the artist for the C64 game, you want Predator style dreadlocks for your character but you have to have a gap between them to show the shape so you can only fit in two, you start with a one pixel eye so you can fit in a mouth but you don't like the way it looks so you change it to being three pixels, now you have no space for a mouth, you have to concentrate on shading for the rest of the head to create separation between head and chest etc etc.

The Wario Land artist has space to do a full face, and they've even created a stylised design so that his head makes up more of the character than normal (in fact I always felt like Nintendo swapped from Mario to Wario on Game Boy specifically for this reason, Mario would look wrong if they made him this wide).

Didn't turn out too good unfortunately heh, had trouble with the screen ratio/resolution amongst other things (I don't think the GX4000 has square pixels)

https://i.ibb.co/J7rrn9f/gx4000-wario-Land.png

The GX4000 has a much higher vertical resolution so it would look a lot better than this if done properly.

Actually if you think of the first Game Boy games then you remember that they actually went for a zoomed out 8-bit console look initially with Mario Land and games like Batman, they were quite blocky, as time went on they made the games more and more zoomed in.

One has to be careful with the "improving" the resolution though. The Sonic GX4000 game uses it for the backgrounds but not for the sprites. In fact, GX4000 sprites are full resolution, they could have used the Mega Drive Sonic sprite instead, but they didn't. Using the high res sprites would give away the lack of detail in the backgrounds.

Game Gear and Gameboy games don't feel "low resolution", they feel like someone took SMS/NES resolution and cropped it.
Sonic GX4000 feels the same way, the extra vertical resolution is mostly used for dithering.
What C64/Atari 800/Amstrad games do though is to use the vertical resolution for detail and then try to workaround the low horizontal resolution, but that gives away the fact that there is detail missing.

Thought I'd try to make a GX4000 mock-up of Batman: The Movie from the Atari ST version

https://i.ibb.co/09bQPsJ/gx-Batman-latest.png

Unfortunately its a bit too close up I think, heh, Batman requires five odd sprites like this, and then there's the Bat-rope!

To be honest though if designed for the GX4000 from the ground up (as opposed to just cropping reused art from elsewhere) you would only have to scale back a little to get Batman done with four sprites, and you'd have a lot more viewing area.

If you're willing to spend more time recoloring, this may work out better

https://www.youtube.com/watch?v=rifmUYXdLu4

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Originally Posted by Thenewguy

Thought I'd try to make a GX4000 mock-up of Batman: The Movie from the Atari ST version

https://i.ibb.co/09bQPsJ/gx-Batman-latest.png

Unfortunately its a bit too close up I think, heh, Batman requires five odd sprites like this, and then there's the Bat-rope!

To be honest though if designed for the GX4000 from the ground up (as opposed to just cropping reused art from elsewhere) you would only have to scale back a little to get Batman done with four sprites, and you'd have a lot more viewing area.

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I actually really like how this looks.:)

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Originally Posted by Thenewguy

Thought I'd try to make a GX4000 mock-up of Batman: The Movie from the Atari ST version

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Makes me think of what a home version of the Atari Lynx might have been like, not a very good idea :lol:
It does look nice though.

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Originally Posted by Sik

If you're willing to spend more time recoloring, this may work out better

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I wanted to do Batman: The Movie because it was a big game in Britain at the time, and in an alternate reality where the GX4000 sold well Ocean would likely have been one of the main supporters of the machine. Also Batman: The Movie did actually come out on GX4000 but was a straight Amstrad CPC port that didn't use the GX4000 hardware scrolling or sprites, so I wanted to try to think of what it would have looked like if they'd done a proper job with a decent sized team.

Here's the actual release version of Batman: The Movie on GX4000 -

https://i.ibb.co/18yRvpF/batman.png

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Originally Posted by Leynos

I actually really like how this looks.:)

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Thanks dude, I tried to scale it down to 75% to decrease its sprite needs as well -

https://i.ibb.co/FHgjsTy/batman-resized-gx4000.png

I think I prefer the original mock-up, but I'm not sure the GX4000 could actually handle it, I remember that the sprites of the GX4000 are pretty pathetic, but I can't remember just how pathetic. GX4000 would have to do the Bat-rope with software sprites too as there's no way there'd be enough hardware sprites to do that on top of the player and enemies at that scale.

Well, GX4000 seems to use the CPC+ ASIC, so looking up that gives:
http://www.cpcwiki.eu/index.php/Prog..._sprite_format

• Up to 16 sprites
• Sprites are 16×16 in size
• 15 colors (+ transparent)
• Magnification 1x, 2x, 4x (set per sprite)

Multiplexing is doable, but there's the problem that the address for the graphic is fixed, so just multiplexing sprites isn't enough unless you're trying to repeat a sprite (can be useful for some objects but probably not all of them). If the distance is large enough you could attempt rewriting the graphic on the fly, though that's a waste of CPU time. It still could be useful if you really need.

I guess the big problem here is the combination of 16px width and limited multiplexing. C64 only has eight sprites, but they're 24×24 so in simple cases you can get away with no multiplexing at all, and when you do need multiplexing you can swap the graphic's address as needed.

Yeah I thought there might be a problem with animating the sprites, but thinking back I think this was strictly about the multiplexing, I believe the thing I was reading stated that you needed each animation frame to take up a sprite slot, otherwise when they're multiplexed all of the sprites would animate in unison.

I think it was something like that anyway.

I don't think multiplexing is viable on the GX4000, if you are using the 2x size mode then each sprite is covering 32px worth of the screen on a 320px resolution, so you only need 10 sprites to cover the full screen width, which is quite overkill for an 8bit machine.

Remember that the C64 sprites are actually 12x24 when using the low resolution mode (but double width to 24x24), whereas the GX4000 sprites are 16x16 but 32x32 pixels worth in double width and height, they're much better. The GX4000 also does not need any sprite layering, while the C64 often does, and many C64 games don't have more than 16 sprites onscreen even with multiplexing going on.

For really large enemies you could make them 4x size and ridiculously pixelated. Sounds bad but you could pass it off as a "cool scaling effect". Astro Boy on the GBA does that even though it doesn't need to and nobody seems to mind.

Also remember that the GX4000 uses a bitmapped display and software sprites are pretty easy. Small bullets, the rope, mostly stationary enemies, you can do a lot!

Yeah, when I said 24×24 I meant on-screen coverage. But that's also without magnification, they're 48px wide when magnified lol. In any case I was pointing out that since C64's sprites were larger that multiplexing wasn't that critical.

But with 16×16 then multiplexing would be the way to go. Except because the addresses are fixed, so it's not just a matter of swapping a few registers but you outright have to load new graphics which is a lot more of values to write (that's 128 bytes + register writes per sprite, which is a lot).

The background is indeed a bitmap, but from what I recall there's no blitter like on the Amiga, so softrendering sprites is slow.