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The art and engineering of Sega CD Silpheed

fabiensanglard.net

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Re: The art and engineering of Sega CD Silpheed

#31
If you've never seen Overdrive 2 by Titan (a demo scene group), it's unbelievable what the MegaDrive can do stock.

https://www.youtube.com/watch?v=gWVmPtr9O0g

I'm reasonably familiar with the hardware, I've written some games from scratch and I still have absolutely no idea how they did most of it.

Re: The art and engineering of Sega CD Silpheed

#32

I think the article is sorta wrong about the sound setup, the Mega Drive I does have a sound input on the expansion port, and mixes it into its sound output. Otherwise stuff like RF cables wouldn't get Mega CD based audio (and you can do silly stuff like a Mega Drive II, which doesn't have a headphone port, with a Mega CD I). I was going to say the patch cable setup was just a passive aid to take the Mega Drive I's m…

So the problem with the Model 1 that the mixing cable is trying to solve is that the expansion port on that model has audio input pins, but no audio output pins. Now strictly speaking, this is sufficient if you just want to use the MD1's headphone jack (stereo) or A/V out (mono), but in addition to the analog audio circuitry not being amazing (though honestly the MD1 is much better than the MD2 here in general) it also imposes a fairly aggressive low-pass filter. This is rather undesirable for 44.1 kHz CDDA. As you note, the mixing cable allows the RCA outputs to be mixed on the CD hardware side which works around this issue.

On the MD2, they added audio output pins to the expansion port in addition to the existing audio input pins. This allows them to achieve the same effect with no mixing cable.

Re: The art and engineering of Sega CD Silpheed

#33

> That was a departure from how I normally work since I did not write a single line of code. I will likely write something about my A.I framework (and opensource it) next month. If the author is around, super curious how they got to enjoy their workflow here in a side project, working with AI. This kind of situation, to me, is often where the joy is gone.

I have a writeup I want to publish about it.

- I felt like Tony Stark inverting Möbius strip to solve time-space navigation with AI.

- Any idea or gut feeling I had, I could verify very fast.

- I had to write a mini Genesis emulator to test the pipeline and it was very pleasant to direct the LLM to write it for me (with clean code and architecture).

Re: The art and engineering of Sega CD Silpheed

#34
post #5

This was submitted by a bot :D I subscribe to Fabien's RSS and he must have changed something in the server because I got this post on my RSS reader (again, as it's an old post), and here it is submitted to HN (again)

I manage my RSS by hand (I should really fix this) and update it when I am ready to publish something.

Someone emailed me to tell I had a typo in the URL of the Silpheed article. This must have unlocked the bot maybe?

Re: The art and engineering of Sega CD Silpheed

#36
post #3

Cool article, but Silpheed is a genuinely awful game. Just warning if you are tempted to play it after this lol

The DOS version has a special place in my heart. I memorized the opening text and thought it was an eerie and cool bit of original poetry, before learning much later that it was a quote from Shakespeare's _Julius Caesar_. I still remember my preferred weapon loadout.

Yeah, it doesn't hold up by today's standards, but it was stunning in its day.

Re: The art and engineering of Sega CD Silpheed

#37
post #3

Cool article, but Silpheed is a genuinely awful game. Just warning if you are tempted to play it after this lol

Somewhat enjoyed the (less-visually-impressive) PC version way back in the day, there weren't many good shoot-em-ups on a 286 PC that could barely scroll the screen, but Silpheed played fairly well on it, and IIRC it was one of the few games that supported the non-standard sound card on my parents IBM PS/1. Actually think it might have been bundled with that PS/1

> one of the few games that supported the non-standard sound card on my parents IBM PS/1. Actually think it might have been bundled with that PS/1

It was.

https://pixelatedarcade.com/tech_attributes/overview/ibm-ps-...

Re: The art and engineering of Sega CD Silpheed

#38
post #4

The Sega CD is my favorite console and I was fortunate enough to have one growing up. Silpheed was unlike anything else. Unlike most FMV games, Silpheed actually felt like controlling a movie. During the first level when laser blasts are tearing through the fleet gigantic ships filling the screen with debris, I could barely believe what I was seeing. As the article points out, while it is an FMV game, it tries to foo…

The soundtrack is absolutely phenomenal. I pull it up on Youtube once a year or so just for kicks. Silpheed by Sierra On-Line for the PC — ported from the Japanese PC-8801 — was similarly good, possibly the first game I played with a proper sound card. The MT-32 version blew my twelve-year-old mind.

Agreed :) lots here to play with: https://chiptune.app?q=silpheed

Re: The art and engineering of Sega CD Silpheed

#39

https://youtu.be/IehwV2K60r8?is=WWZU3R1PMAQksHhj How they fit the Sonic 3D intro onto a sega mega drive _cartridge_!

Summary:

It's low resolution at only 256 x 80, stretched vertically to the screen size.

It's only 16 colors so only 4 bits/pixel.

That comes to 10kb per frame.

A variant of Huffman coding gets it to 3.52kb per frame.

It's at 15 fps and is 12.5 seconds in length.

15 x 12.5 x 3.52kb = 660kb, which fits in a 4mb cartridge.

There is dithering to give the appearance of more colors, and it's done in vertical stripes rather than checkerboards because that compresses better. Then at runtime, every other scanline is offset by 1 pixel, and in opposite directions every other frame, so the dithering blurs back together to give the appearance of many more colors.

Re: The art and engineering of Sega CD Silpheed

#40
post #11

Earlier quoted context omitted.

From the article: > I spent the past two weeks reverse engineering the FMV format in my spare time. That was a departure from how I normally work since I did not write a single line of code. I will likely write something about my A.I framework (and opensource it) next month. But I can already tell this is an overall pleasant way to work.

It's tremendously disappointing to see Fabien stoop to using slop for his research; completely antithetical to the love for software craftsmanship I had inferred from his previous work.

I am curious to understand why you are disappointed.

I used A.I to write code on a personal project. It allowed me to go much faster than if I had tried by hand. Given my time constraints, it is likely I would have never found the time to complete this project.

The article was entirely written by me without A.I.

Please, help me to understand.

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