Fully documented source code for Lander on the Acorn Archimedes | Hacker News Reader

Fully documented source code for Lander on the Acorn Archimedes

github.com

74 pointsKye26 comments

That's great for analyzing or reviewing the code. However, beyond that, there's not much else you can do with this code.

   This repository is not provided with a licence, and there is intentionally no LICENSE file provided.

   According to GitHub's licensing documentation, this means that "the default copyright laws apply, meaning that you retain all rights to your source code and no one may reproduce, distribute, or create derivative works from your work".

Yeah, I’ve had to add the same disclaimer to all my analyses of old code (e.g. Elite, Revs, Aviator). I’m not sure there’s any other solution - the original copyright owners still hold the copyright, and that’s just how it is. You can’t grant a license if you don’t own the rights…

Thr original author of lander is still about and on social media, it may be worth asking.

Lander was a demo which evolved into the full game Zarch, known as Virus on other platforms.

https://en.m.wikipedia.org/wiki/Zarch

It seems that the software can be run in-browser here: https://archi.medes.live/

An Archimedes in the browser, Nostalgia overload!

I'm a little rusty, but I can still use it. Seems like things you learn when you're young stick with you, even if you haven't done it in over a decade.

Thank you for linking this, Smoosh!

The Archimedes had a mouse, so it is mouse-controlled in case anyone was wondering!

I'd love to add a touchpad-style control to make this usable on mobile. This seems like something someone should have made before, but I've not found anything suitable.

Tilt the phone to control could work for this.

Direct link if you want to try out Lander: https://archi.medes.live/#disc=lander&autoboot

Also, since it was on here yesterday here's Lemmings: https://archi.medes.live/#disc=lemmings-demo&autoboot

The Archimedes probably had the best port of Lemmings from the original Amiga version, including (IMHO) even better music tracks than the original.

Fresh out of school I started a job that involved updating some assembly code.

I came across:

#transfer the value from address 0x600 into R0

Mov &0x600, R0

... several lines later ...

#transfer the value in R0 to R1

Mov R1, R0

I puzzled over this while reading the rest of the program which had been similarly commented line for line and then eventually, there being no manuals, asked an older coworker to explain what was going on.

He looked at me with incredulity and said "what makes you think the comments have anything to do with the code?"

He explained "about 10 years ago the mechanical engineer finally got this program to work and his boss told him to explain what every line did, so he added the comments. The code has been updated for 10 years and no one's bothered to update the comments."

I have noticed that this is a truth throughout the rest of my career, although I have heard that NASA has someone whose job it is during code reviews specifically to make sure that the comments are kept up to date.

In just about every code base I have come across, 3/4 of the comments are wrong or unnecessary, and there is at least 1/4 of comments entirely missing to explain the inexplicable.

Managing comments is one thing I really appreciate AI helping me with in cursor.so, I can ask it to strip all the comments to get a dense code view, make some changes, then re-comment it, with the verbosity aligned with my level of understanding.

I remember playing this for the first time and being absolutely stunned. I think it would have been on an A3000, and up to then, the only machines I'd used were BBC micros and a Mac 512, neither of which were capable of anything like this. It was like science fiction.

This is written in Arm assembly language, for (I think) the ARM 2 CPU.

Se the history section: https://en.wikipedia.org/wiki/ARM_architecture_family

Technically, Lander was written for the ARM1, as it originated on an Acorn ARM Evaluation System. As a result there are no MUL instructions in Lander, as they only got added in the ARM2.

That makes Lander first ever ARM game, and probably the only game ever written for the ARM1.

A demo run of the original on a real system: https://www.youtube.com/watch?v=mFwpsb75omg

Back in the days I wanted to get an Archimedes, moving away from my Amiga A4k40 but it was hard to get in Germany. I did get a Bebox instead. Sadly, both were killed by PCs with GPUs.

So can we extract the complete map from this? Where is that defined?

It is procedurally generated (of course it is, this is David Braben we’re talking about!).

I’ve written a deep dive on how it works, here:

https://lander.bbcelite.com/deep_dives/generating_the_landsc...

It’s basically a Fourier analysis. Very, very clever!

Perhaps a Fourier synthesis rather than an analysis, since there was no original map analysed into waves, but indeed, highly ingenious. Thank you for writing that article!

That's a good point - I wondered what the correct term was, and Fourier synthesis makes a lot more sense! I will update the article accordingly; thank you for pointing that out.

OK, I need to see how the ship shadow was done.

The coordinates of the shadow are calculated here:

https://lander.bbcelite.com/source/main/subroutine/drawobjec...

and they are drawn here:

https://lander.bbcelite.com/source/main/subroutine/drawobjec...

The shadow is a very simple projection straight down onto the landscape, which isn’t totally accurate, but it’s quick and easy and looks good enough. The shadow doesn’t drape over the shape of the landscape, and the ship shadow appears on the ground beneath objects rather than on top of them, but you don’t really notice.

Lovely, simple, effective code. Much like the rest of Lander, really!

Amazing work!

Indeed. Although I was hoping to see units on variables for altitude, velocity. (Maybe that's documented elsewhere?)

In terms of scale, there is the concept of the tile size, which is set to 0x01000000, and everything uses the same coordinate units, so it’s possible to extrapolate this to give some sense of scale.

You can see the configuration variables here:

https://lander.bbcelite.com/source/all/workspaces.html

I’ll probably add more scaling information as I do the deep dives.

And now I post that I see that I have failed to link to this file from the left nav, which won’t have helped! So I’ll sort that out…

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