Transcoded Arcade Games for the CoCo 3

Hello, friends,
Sorry I'm a little late. This week's been a bit crazy.
Since I was rushed, I decided to follow up on the MWPC from earlier in the week looking at the #CoCo3, #CoCoSDC, #Switcharoo and #RGBtoHDMI.
This time, we're looking at the six transcoded arcade games I mentioned: #DonkeyKong, #Defender, #Joust, #Robotron2084, #PacMan and #SpaceInvaders.
I hope you enjoy it!
Thank you for watching
Todd
TRS-80 Color Computer Archive:
colorcomputerarchive.com/
Where to buy the RGBtoHDMI in the States:
retrohackshack.com/product/rg...
Where to buy the Switch-a-roo:
cocoman.onlineweb.shop/Switch...
Where to buy the CoCo SDC:
retrorewind.ca/coco-sdc
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[@captaincorleone7088]

Wow, that's really impressive. Those conversions are close enough that I would be delighted with them. As you pointed out, they showcase what the CoCo 3 was capable of - in the right hands. Thanks for sharing!

[@YARC-1981]

You're welcome and thanks for watching!

[@CurtisBoyle]

There is also a transcode of the original Apple II+ Lode Runner to the Coco 3 as well (I didn't mention it earlier since it is a transcode of a home computer game vs. an arcade game, but the same techniques were done (6502 to 6809 in this case). As for the 6 arcade transcodes, the graphics on the original systems had the different rotation (that you mentioned in Space Invaders) that has to be corrected for, some palette translations (the Williams games I believe had 256 color palette to choose from; the Coco 3 only has 64), analog to digital joystick conversions, and they had sound chips while the Coco 3 has to drive it's 6 bit DAC in real time, completely driven by the CPU. In most of the transcodes, to keep the speed up, digitized samples were used rather than manipulating waveforms and envelopes with direct emulation (although I *think* John mentioned that he did do real time conversions on the fly for Donkey Kong). That is one part of Robotron:2084 that is not quite finished; only some sound samples are included in that one; hopefully Glen will update it with the full set at some point (although right now he is busy working on seeing if he can transcode an Amiga game to the Coco 3).

[@YARC-1981]

Thank you! I had trouble finding any detail of the process used to include in the video. That's very interesting.

[@Retro4u]

That’s great love the Pac-Man and space invaders. I can comment on the machine I never seen one. Love you showing the machines we don’t see in the UK keep up the great work

[@YARC-1981]

Thanks, Neil!

[@JosipRetroBits]

Donkey Kong conversion looks awesome! This game brings some fun childhood memories :) Cheers!

[@YARC-1981]

Glad you enjoyed it. Thanks, Josip.

[@8BitRetroReFix]

Awesome looking ports .. very close to the arcade .. shows the coco is very capable .. thanks for share mate 👍

[@YARC-1981]

Thanks, Steve!

[@AlexEvans1]

Shift-1 will mount an image in drive 1. You can then mount and start the other in drive 0.

[@YARC-1981]

Thanks!

[@nowhereman999]

Great video showcasing what the CoCo 3 is capable of! That video capture device you're using is excellent! Cheers!

[@YARC-1981]

Thank you, Mr. Hewlett! It's the Elgato Cam Link Pro. I love the work you've done and I'm anxious to see what you've got next.

[@CaptainCommodore]

That's really impressive , had no idea about the coco3 as there little or no expository to them over in the UK, I'm fairly certain though that the 6809 was used a lot in arcade games, I'm sure defender at least used it ?

[@YARC-1981]

From what I can find online, the three Williams games were 6809's. The other three were Z80's and one Intel 8080. The three Williams games would have obviously been a lot easier to transcode as it would have just involved translating the sections that applied to the specific hardware architecture of the arcade cabinet versus the CoCo. Donkey Kong: Zilog Z80, Defender: Motorola 6809, Joust: Motorola 6809, Robotron: Motorola 6809, Pac-Man: Zilog Z80, Space Invaders: Intel 8080

[@ukcroupier]

I was just about to post the same thing. Now I have another machine on my list to buy, this will be a tough one to find, I'm not even sure if the coco 3 was released in the UK.

[@senilyDeluxe]

At exactly 22:10 Pac Man is passing through Blinky. (there's also a version of Pac Man on Commodore 64 where you have to rotate the screen)

[@YARC-1981]

I noticed that when I was recording it. Collision detection fail. Thanks.

[@YARC-1981]

I did sent a message to Glen Hewlett about this, but I doubt he'll address it. He's currently working on porting some Amiga software to the CoCo3.

[@fnjesusfreak]

There's a few "tate" clones of Pac-Man on the Apple ][ as well.

[@greenknight9000]

That's actually completely intended behaviour! It was a bug/oversight in the original Arcade version where If Pac-Man and a Ghost cross over the same tile at the same time, they won't actually "collide" and he'll go right through them! It just shows how amazingly accurate this code transcribe was

[@MarcusLlewellyn]

Before I finally got a computer when I was a kid, I wanted to go into every Radio Shack just so I could salivate over all the Tandy computers and peripherals, while also looking at the price tags and knowing I'd never, ever get one. 🤑

[@YARC-1981]

Yeah. Adrian's Digital Basement second channel had an old Radio Shack catalog last week and was marveling over the prices. The CoCo's weren't too bad since they were aimed at the home market, but the "business" class machines were outrageous. Thanks for watching!

[@elfenmagix8173]

Interesting as Defender/Stargate, Joust and. Robotron were running on the 68000 cpu

[@YARC-1981]

The information I have access to says that the arcade cabinets for these three used the 6809 CPU. Thanks for watching!

[@fnjesusfreak]

Pretty sure they ran on 6809 same as the CoCo

[@beeryefpv8212]

They were on a 6809.

[@aerotube7291]

Had a good version of this on coco 1

[@YARC-1981]

Version of which?

[@aerotube7291]

@@YARC-1981 joust(the bird game)

[@aerotube7291]

@@YARC-1981 was upgraded to 64k, microdeal version I think

[@aerotube7291]

Oh, donkey(king) too, both played well mode 3, as did time bandit. Others looked better in bw but we never got the artifact colors in the UK...

[@aerotube7291]

@@YARC-1981 my father sent his world map program to hot coco and had it published! He got lots of requests from USA on if he knew how to implement the artifact colours. Great days

[@CoCoNutBob]

In SCD Explorer, press Shift+M to mount a directory with multiple images, them simply press the button to cycle through the numbers disk images. The led flashes the appropriate number of times to indicate which image you're on. Try it with Sinistaar (3 disks) Also, there appears to be a clone of Konami's Tutankhaman arcade games that plays sideways, just fyi.

[@YARC-1981]

Thanks for the info and for watching! I spend so much time working on the hardware/electronics side of things that I never set aside enough time to learn to fully use anything. I've had the CoCoSDC for over a year and still don't know all the ins-and-outs.

[@jinchoung]

what the heck... those aren't really "ports". they're the actual arcade code. wow how powerful is the coco3????

[@YARC-1981]

More powerful than everybody gave it credit for. Thanks for watching!

[@Alianger]

What does it use for sound, is it all sample-based here?

[@YARC-1981]

I don't actually know, but I'm guessing samples. If you want more information, I know at least Glen Hewlett is approachable.

[@andre0000000007]

all awesome, pity about pacman screen scrolling though :(

[@YARC-1981]

Yeah. I don't know if Glen will ever finish this one.

[@Anangelspath]

Were original arcade graphic chips similar to the coco3 or ports accessing add on hardware?

[@YARC-1981]

I don't know all the details of how these were done, but I believe they emulated the hardware. The only hardware requirement for the CoCo3 to run these is a 512KB or greater memory expansion. No other modifications are needed.

[@sock_master]

The graphics hardware for most of these arcade games is different from each other and also very different from the CoCo3's graphics hardware. Donkey Kong and Pac-Man for instance have tile based graphics with sprites but the CoCo3 only supports bitmapped graphics, so the nature of the graphics hardware had to be entirely emulated in software. In the case of Donkey Kong, the arcade hardware supports a *huge* number of simultaneous sprites (96!) and the majority of the CoCo CPU's time is spent simply emulating the graphics while running the game code itself only takes a fraction of the CPU's time. In all cases for these games, a *lot* of code optimization had to be done in order to squeeze the maximum possible performance out of the CoCo 3.

[@YARC-1981]

Great information. Thank you!

[@doctorx0079]

​@@sock_masterDo you think the CoCo 3 would be capable of a transcode of Ghosts n Goblins? It uses a 6809.

[@sock_master]

@@doctorx0079 I don't think it's possible. GnG has a 6809 running at 6Mhz, plus multiplane graphics with sprites on top of that. Plus a whole other CPU and sound chips for sound. The CoCo 3 at 1.79Mhz would have no hope of keeping up with all that. The complexity of arcade games increased every year and games from around 1982 give or take are about the limit.

[@gsestream]

so I assume ton of nethack and/or adom, lmao

[@YARC-1981]

I'm not sure how Nethack or Ancient Domains of Mystery relate to the content of this video. For those who are unaware, so was I. Nethack and ADOM, according to the Google-ing I did, are 'roguelike' RPGs

[@gsestream]

yet another ascension? oh you have not finished it yet, or even played it, assumed retro would absolutely include both of those titles@@YARC-1981

[@gsestream]

channel name of course. did not get to the actual content yet, of the video.@@YARC-1981

[@YARC-1981]

@@gsestream I'm still unclear unless you're referring to the little wizard in my channel logo. He's from an 80's game on the TRS-80 Color Computer called Dungeons of Daggorath.

[@gsestream]

I just assumed you were referring by your channel name, to the adom/nethack YAA "yet another ....." type of victory, but seems you were not. oh well.@@YARC-1981