Early morning post of this week in gamedev!

ZX Spectrum 48K

After implementing support for floating bus –that at the end works in all models, with fall-back to vsync; useful for clones and inaccurate emulators–, I continued adding features to the engine:

• Tweaks to the jump and gravity.
• Collision detection for the enemies, so the player can lose lives and die.
• Pick ups, that will be an important component in the game (key/door puzzles).
• One special pick up: “the blaster”. I’ve decided to replicate the behaviour I used in Castaway, so the blaster needs time to charge between shots. In Castaway that was to hide a limitation of the engine, but in this game I like it because it adds strategy!
• And, of course, lots of fixes (with new bugs introduced, probably).

Some of these features were difficult to implement. This is the first time I’m working with a XOR engine –the sprites are drawn using the XOR function, and erased applying the same function with the same exact sprite–, and works well, but it is tricky to add or remove entities mid-loop.

At the end the solution was clean: I just needed to adjust the process by adding an extra draw or erase when I add or remove an entity mid-loop. For example: when the player uses the blaster, the game loop expects the projectile sprite to be there to be erased before drawing the next frame, so I have to perform one extra draw so there’s something to erase.

This is done sometimes out of sync, or waiting for the floating bus if is a big change –for example: erase an enemy that is being destroyed and draw the first frame of the explosion–, and in general the result is very nice. Not completely perfect when the drawing happens on the top of the screen, but this is one of the cases where aiming for perfection wouldn’t be useful.

Currently I only have implemented the “extra life” and the blaster pick ups, and any other is just added to the inventory –not really, is just drawing them in the HUD–. I added support for persistence via a bitmap, so those items don’t respawn and I can check for the specific bit as a flag to see if the player has collected that pick up.

For now the enemies respawn when you leave and re-enter the screen, but I may experiment with some ideas. For example: the enemies’ respawn could be conditional, making the game a bit more interesting and opening the door to some exciting game design.

I’m trying to decide what I’m going to do with the game map. I started using a basic 8-bit per tile map with compression, like in Brick Rick (for the ZX Spectrum), because it is easy and allowed me to progress with the engine, but the screens use a bit too much memory. That wasn’t a problem with Brick Rick because I was aiming to the 128K models, but this game is 48K.

I have used different approaches in different projects, so at this point I don’t think I’m going to find anything ground-breaking that I haven’t used before. It is more about deciding that I’m going to be happy with the restrictions the encoding will introduce. For example, Kitsune’s Curse uses packing with 4-bit per tile plus some programmatic definitions of the map, with the downside of having to define tilesets of 16 tiles –not the end of the world, but makes level design a bit harder–.

I have some ideas that are a variation of what I used in Brick Rick (for the Amstrad CPC this time), but I’m not too excited because it is an encoding that would make using tiled less nice, although it could reduce the maps about 50% compared with current memory wasting encoding.

Meanwhile, the game doesn’t have a name yet. It is more and more likely that it will be a sequel –or prequel?– to Castaway, so perhaps I should use the name I had planned for that: Starblind.

More MSX RPG

I have started exploring a bit of code for that crazy idea of making a CRPG –which I guess is more a western role playing game than a classic JRPG; oh, labels!–.

Currently I have a nice menu system, but I’m struggling with the MSX1 restrictions; and I don’t want to use MSX2. Which is not a complete waste of time, because I’m getting to the conclusion that I should focus on what is that the MSX can do, and then implement the mechanics I want for the game.

Later on I could get the core of the engine and, perhaps, use a different 8-bit system to implement the game I had in mind initially. But that sounds like a project for next year, so we will see!

A couple of days ago I added some sound effects to my ZX Spectrum 48K “work in progress” game, and I found that the few cycles the beeper engine uses in the interrupt handler broke my tight timing and, specially on the top of the screen, there will be flicker when drawing a few sprites on the same line. Which is a shame.

Initially I thought that it wasn’t a big deal but, because how I decided to implement coloured sprites, the flickering is specially ugly –to my eyes, at least–. So I knew about a technique that allows you some extra time besides the one you get by syncing with the interrupt: The Definitive Programmer’s Guide to Using the Floating Bus Trick on the ZX Spectrum, by Ast A. Moore.

From that page:

In the context of the ZX Spectrum, the floating bus trick refers to exploiting a hardware quirk of these machines, where a value being read by the ULA from the data bus can also be read by the CPU.

Which in a nutshell means you can prepare some specific data on screen, usually in the colour attributes, and listen to the ULA using the floating bus trick to sync with it when it is processing that specific data.

For example: in my game I have drawn a “HUD” –head-up display; in a computer game, the part of the screen that shows information like the number of lives left or the score– with a specific colour attribute not used anywhere else in the game, and then I have a specifically timed routine that listens the floating bus to wait until the ULA is processing those attributes. Because the attributes are in the bottom of the drawable screen, I get extra time to draw my sprites –the HUD and the bottom border–.

On that screenshot of the game I’m drawing a red line on the border when I sync with the HUD attributes after listening to the floating bus. And with that extra time, the flickering is gone!

Initially it was thought that this trick didn’t work on +2A/+3 models. I had a +2A back in the day and I can confirm that a lot of games –specially for 48K models– didn’t work on my machine. Ast did some excellent research a few years ago and he came up with an implementation for those models. It only took 30 years!

Just as an example –you should read Ast’s article–, this is my current version of the code:

; HUD attr: bright paper cyan, black ink
; will OR 1 in +2A/+3 models
BUS_ATTR equ 0x68

wait_bus:
        ld a, (0x0b53)
        cp #0x7e
        jr z, other_bus
wait_bus_loop:
        ld a, #0x40
        in a, (0xff)
        cp #BUS_ATTR
        jp nz, wait_bus_loop
        xor a
        ret
other_bus:
        ld a, (#0x5800)
        ld a, #0x0f
        in a, (0xfd)
        cp #(BUS_ATTR | 1)
        jp nz, other_bus
        xor a
        ret

It looks like the floating bus is tricky to implement on emulators. The “classic” floating bus is perfectly emulated by almost all emulators, but the floating bus of the +2A/+3 models is not widely supported. I don’t have an list, but I have confirmed RVM and CLK support it fine!

I detect the +2A/+3 models and just branch to the special sync code for them. If the floating bus is not there, the code will loop forever. That could be avoided by detecting if the floating bus exists before hand and falling back to use vsync –even if that means flickering sprites–, but that’s probably not necessary as it works in real hardware and most emulators using 48K models.

Oh, looks like it is Thursday again. Let’s see what happened in my gamedev time!

Unnamed programming language

As I mentioned in my previous update, I was investigating a scripting solution, but somehow I got distracted in the process. Which is OK, sometimes these distractions lead to good things.

So far I’ve implemented a recursive descent parser for a C-alike language –although I’m using something closer to Scala syntax–, and I can go through the abstract syntax tree and generate something.

And that was fun, but I need to start writing tests and perhaps emit code so I can prove that my language design makes sense.

If I want to use this in any of my 8-bit projects, I probably want to generate something that is useful in those cases. I could compile to Z80 ASM that integrates well with SDCC tools, which sounds very hard –and very interesting at the same time–; or perhaps bytecode for a simple VM, which is probably easier and a more achievable task.

But then I thought that writing the VM itself would be a non-trivial amount of work, so I had the “brilliant idea” to generate WAT (WebAssembly Text), which looks like ASM that can be compiled to be run in a WA (WebAssembly) virtual machine. And so far has been very interesting, and not as complicated as I was expecting. It is also useful that the nuances of generating code to run on WA are helping me to refine the language design, even if that means I’m also being influenced by WA.

This is a code example:

def fac(acc: dword, n: dword): dword
{
  if (n == 0)
    acc;
  else
    fac(n * acc, n - 1);
}

fac(1, 10);

And this is the resulting WAT code:

(module
  (func (result i32)
    i32.const 1
    i32.const 10
    call $fac
  )
  (func $fac (param $acc i32) (param $n i32) (result i32)
    local.get $n
    i32.const 0
    i32.eq
    if (result i32)
      local.get $acc
    else
      local.get $n
      local.get $acc
      i32.mul
      local.get $n
      i32.const 1
      i32.sub
      call $fac
    end
  )
  (export "lang.main" (func 0))
)

I got to a point where the WAT generation has “revealed” some inconsistencies in my language design and I need to revisit it, which is perfect, because it means the project can grow with less chances of getting to a dead end.

I’m implementing it all in Python with type hints and mypy via a Python LSP server, and I’m really enjoying the experience. Initially I thought the type annotations were slowing me down, but in reality it was all my fault because my code wasn’t great. Now it feels a lot like writing Scala, and it is saving me a lot of time by finding bugs early –plus the better code design to make mypy happy–.

I don’t have a name, and is not a problem; but surely a name would be useful if this project has any future.

More ZX Spectrum 48K coding

Arguably this went a bit cold. Firstly because I spent some time writing a beeper engine, and after that because writing a compiler –see previous point– is fun!

In reality I was thinking about it, because I need a game idea before I can make the game itself. I’m still undecided, but I’m leaning towards a platform game, probably what “Starblind” was going to be before I moved into a more top-down multi-directional scroll idea, that was kind of interesting as a tech demo, but there was never a proper game idea behind it. I’m not looking to make a genre-shaking game, only something that is fun to play and has a good speccy 48K vibe.

I’ve been planning on how to encode the map data reducing the memory footprint as much as possible. In Brick Rick on the speccy 128K I had lots of memory, so I didn’t bother doing anything smart –just good old compression–; but that won’t do it in a 48K game, even if the engine itself doesn’t use a lot of memory. For now I have some ideas on paper, but it is a bit too early to start writing a prototype.

Other than that, I’m trying to clarify what are going to be the features supported by the game engine. So far far I have:

• Flick-screen platforming action, probably with object based puzzles.
• A large map area, or at least not small.
• Different sprite sizes; I’m testing a spaceman sprite that is 16x24 pixels, but enemies are likely to be 16x16.
• Colour sprites for the enemies, because the type of sprites I’m using, the background will be mostly black; so it makes sense to use coloured sprites.
• No buffering, drawing directly on the screen!

And that last point is what has kept me busy this week, mostly.

I knew that my sprite routines aren’t the fastest you can write, but Brick Rick uses hardware double buffer (I write to the back-screen, and swap with the visible screen when finished), so it didn’t matter at all because the game updates a 16FPS, so updating 1 of every 3 frames leaves more than enough time to update the game state and draw.

In this project I don’t have that nice hardware support, and I don’t have memory either! So I’m reducing scope, for example, by using XOR sprites (instead of masked) and limiting the backgrounds (mostly black). But the sprite routines aren’t fast enough to draw enough things in one frame, so I was getting flickering all over the place.

Although I’m still testing, I’ve decided to do something similar to Brick Rick’s approach: if you can’t update all the screen in one frame, that’s fine because our target is not the 50 frames per second but 16. The only difference is that I don’t have a back buffer to compose the scene and then make it visible in one step –or fast enough so there is no flickering–. But, what if I can spread the updates in several frames?

If you run the game slow enough you can see that the sprites are drawn on the screen in groups –or at least that’s what I meant!–, but because all the game state is updated at the same time, is not noticeable.

This is not a technical marvel, is more about hiding that my sprite routines aren’t fast enough. Combined with some code to sort the sprites so the groups are optimal, I can move a good number of thins on screen without any flicker –most of the time, at least!–.

So far I’m happy. I’ll keep testing and if it is confirmed that this idea is stable enough, that may be the base for the game engine!

I know I wrote “remote” on the title of this post, but I have this theory that what I’m going to discuss here is not really a problem with remote pair programming, but with pair programming itself.

In my team we do pair programming, and we like it. We are completely on board with the benefits, and we are happy to assume the few small costs that come with it. Of course, with the COVID situation we have been working from home for over a year now, and we have been doing pair programming remotely; including with team members that have joined the company (and the team) remotely, so we haven’t met in person.

And we have made it work, essentially, using Google Hangouts sharing the screen –which is not very good to be honest, in my experience Skype provides better video quality with less bandwidth–, and that’s basically it. It is exhausting, but in my experience I wouldn’t say more than non-remote pair programming sessions.

Unfortunately this is somewhat limited, because it means that one person is driving, and the other person is in the back-seat. Not having the keyboard doesn’t mean you are not actively contributing, but taking turns driving is too awkward because the code has to be made available to the other person, for example via a WIP branch on a git repo.

There are better options, that allow easily taking turns, or even work on the same code at the same time collaboratively. Some examples of these tools are:

• tmate: for any terminal based editor and tmux aficionados.
• Live Share: for VS Code only, that allows collaboratively edit and debug in real time.

There are a few more options, but these are probably the most popular in my circles.

Looking at my team, we have a very diverse set of skills, and we use very different editors: one vim, one emacs, and two VS Code.

I think it is pretty clear what is the issue if we try to take turns driving a pair programming session, isn’t it? And I have the theory that this is not really a problem with the remote part of it.

I’m sure we would have the same problem if we were in the same office, sharing keyboard an mouse –which I don’t find comfortable at all–. Am I proficient with emacs or VS Code? No, I’m not.

I remember attending a conference back in Guildford –if I recall correctly–, and there was a talk by someone from Pivotal Labs. It was more like they were selling some product, but I remember clearly how they explained their experience with pair programming, and how one of the requirements was that there was one editor, with one configuration, and all the software engineer seats were exactly the same, without any customization.

The idea was that any developer could use any seat to write code like they were on their own computer, basically because all computers were the same (and I may add, they would love if all their engineers were the same and replaceable).

I found that fascinating, and of course I would never want to work on a company like that. By stripping all engineers of any personality and any chance to express themselves through their tools and whatever makes them productive and happy, they optimised their teams for pair programming. I’m not even sure that’s good for the company.

So we keep looking around and checking tools periodically, but I suspect we are not going to find a solution. Because it may come with a price –like the case of Pivotal– that we may not want to pay.

I have released the source code of The Return of Traxtor (CPC), a game written in C for the Amstad CPC (64k or more; so all models).

This is my second open source release after I made public the code of Castaway, for the ZX Spectrum. Looks like there is a trend now!

This one requires SDCC to build, plus some other requirements for different tools. The idea is not to provide a current version of the game, but the game as it was built back in 2015. That means an old version of SDCC is required, mostly because at some point the project changed some of the tools to manage libraries, and that change wasn’t backwards compatible.

This is probably OK because the old versions of the compiler are still available, and the game’s source code is interesting mostly as a reading exercise anyway. The only big warning is that some of the dependencies have bugs that have been fixed in later releases, so if you want to start a new project, don’t use the versions included in this repo!

Surprisingly enough, this project doesn’t have anything really embarrassing, although is not what I would call a “current” code base. It is poorly organised, with one big file, and SDCC is not the fastest compiler out there. Despite that, overall I think it is still very readable and could be useful to learn a bit about making games in C for the Amstrad CPC.

When I was testing that the game was building correctly, I’m pleased to say that it is still fun puzzle game with cracking music (if I say so myself).

Finally, I don’t plan to provide any support. I know I said that when I released Castaway and then I accepted a contribution to make the codebase compile with a current version of Z88DK; but I really mean it: if you want to compile the game, you are on your own! There may be some bumps, but take it as part of the learning experience.

If you’re gamedev, doesn’t matter if retro or not, I recommend you reading the complete guide for open sourcing video games.

This week has flown by, and my day job has been quite draining, but today is Thursday and that means gamedev update!

Released my ZX Spectrum 48k beeper engine

That could explain why this week I have been a bit low, because working on this little project was kind of intense, and when one of those ends, it always leaves some emptiness.

The project lives in beeper engine for the ZX Spectrum 48K, in GitHub.

Although it is ready to use, there are some things that I may probably add later on:

• More ASM versions of the player. Currently I provide the primary source for he SDCC assembler, that is not the most common syntax. I hope other people using it will contribute other versions.
• Currently the player doesn’t preserve the border color (and there’s a FIXME for that). I may or may not use that, but I guess it is something that is missing for general use.

Everything else is in place and working, to the extent that I have tested it, of course. I’m mostly concerned about the editor having bugs, but I will fix those when they are reported.

Investigating a scripting solution

Although most of my games are very data driven, I have never implemented scripting for any of them. We are talking 8-bit games here, so is not about making the games extensible, but to save memory by using very high level functions in a very dense virtual machine (the script would be more like bytecode).

Looking at existing art that is open source, Na_th_an (from Mojon Twins fame), has implemented scripting on his MK1 NES engine, with a compiler written in BASIC –I love it–.

This solution is very close to the data driven approach I’ve used for example in Rescuing Orc and Dawn of Kernel, were all the data is entered using tiled, and then packed into binary by a Python script.

In Dawn of Kernel for example, there’s a “text” event that, when present, it will display a message from Kernel –the enemy IA–. That saves space and makes game design easier, but there’s no game logic on that data, and that’s something the scripting engine should support.

In reality I should start a project, and then look to implement a simple scripting engine if I need it. Ah, if only things were that simple!

Anyway, I’ve always been into programming languages –specially compilers and interpreters–. Together with operating system design, those topics were my main interest back in Uni. Fortunately I gave up with the operating system part, but every now and then I have the itch to implement a programming language. From silly toy languages to a 6502 VM for 8-bit AVR, so getting myself to write such an engine can be dangerous for my free time!

For now I’ve looking to some interesting resources:

• Build your own Lisp
• Crafting interpreters (I have read Game Programming Patterns by Robert Nystrom as well, and is great)
• Micro parser combinators (in C)

The idea would be around the following points:

• A high level language to access and manipulate game state.
• A compiler to translate that language to bytecode.
• Execute the bytecode in a tight VM, written in the target platform (likely to be Z80).
• Integrate the VM in the game loop.

I’m not sure if is worth moving all the entity information I usually encode in the map data into this language, because the way it works now is very optimal and I really like using tiled to place the entities in the map –it makes game design nicer–. Perhaps this is about including labels on the script and refer to those labels in the map data, so a part of the script is run as an entity. That could allow supporting game logic easily, keeping the benefit of both approaches.

Hopefully I’ll start a project soon and we will see if any of this makes any sense!

Is it Thursday? No, but is close enough to see what happened this week in gamedev!

ZX Spectrum 48K beeper engine

I have always been fascinated by the different beeper sound engines produced in the 80s for the ZX Spectrum, and some of the modern ones too –see the work of utz/irrlicht project–. It is truly amazing how that sounds, considering that it is 1-bit audio.

Until now I was happy using the tools/engines released by Shiru, his BeepFX is probably the best you can get in 1-bit audio. There is a downside though, because to reach that level of sound quality, it has to use all the Z80 CPU actively, and that means interrupting your game. If the sounds are short enough is OK, but not perfect.

So a potential solution to this is running a beeper engine from the interrupt, which means the sound quality will be low because the Spectrum has only one interruption at 50Hz, and limiting the time you spend by frame so the sound won’t interrupt the game’s action (noticeably, at least; we know the interrupt interrupts). And you can also stop the sound being played, replacing it with another sound every 50Hz.

I’ve been working on an engine that is borrowing ideas from the engine used by Steve Turner in games such as Ranarama. Although there’s an disassembly of his routines –allegedly, I can’t confirm that is his code–, I don’t want to use it without permission and I feel it is too complicated and has features that, honestly, I don’t fully understand how to use.

My engine supports two types of sound: tone (square) and noise (random). Both can last for a specific number of frames, support a configurable frequency (that can “slide”), and is possible to link effects.

The engine is small, uses little CPU, and each effect is 4 bytes. Obviously I could support more things, but I feel I can get enough range of sounds to make a game without getting too deep in all the details Turner uses in his engine. The sound quality is low anyway, so for example it is very hard to tell the difference between square and sawtooth waves.

I’m also working on a sound editor, that uses a Z80 emulator library to run the Z80 player and collect sound samples to play the audio on a PC that is very close to what you get on a ZX Spectrum emulator.

I’m not sure how far I’m going to get with this, but it is likely I will release the final product as open source for anyone to use (with out without modifications, so you can change anything you don’t like).

I’ve been posting on Twitter, because after the Brick Rick: Graveyard Shift release I went back to engage; but that will stop and return to very low intensity –I don’t even have a Twitter client on my phone–, because I haven’t changed my mind.

So that means one thing: it is Thursday and that here comes another gamedev update!

ubox MSX lib release

This is a maintenance release that basically fixes a potential problem when changing song with the play function being active in the interrupt handler.

I have used that same code in several games, and you only need to be a bit careful and wait for vsync before changing the song, to ensure that the code will finish before being interrupted. Given that this is a library for others to use, I have decided that it makes more sense to avoid interrupts explicitly.

I had the change in the repo for a while, and I still have a couple of things in my TODO, but the fix deserves a release just in case there is someone out there working on a game.

Targeting the ZX Spectrum 48K

When I was working on “Graveyard Shift” I half added support for 48K games, only that… it wasn’t really working.

The library I wrote for Brick Rick on the speccy is for the 128K models only because it uses double buffer by hardware (and therefore, memory banks), so a lot of code targets 0xc000 as video memory instead of 0x4000.

I have reviewed that code and made a few things configurable:

• By disabling the 128K support, all the tables are using the 48K memory addresses; and the bank changing code won’t work –48K models anyway–.
• The interrupt setup code is now fully configurable, so for example the 257 bytes table for the Z80’s IM 2 can be located at a high address (on the 128K models can’t be over 0xc000 because of the banks).

At the moment the same library can be configured at compilation time to target 128K or 48K, which is perfect.

I have a work in progress memory map that should work great for 48K games:

This leaves probably too much memory for the library and the stack, but for now I think is fine. I may move non speed-sensitive library code to that 0xf900 address, so I have more space for the game itself.

In my TODO there is also some sort of support to build a 128K version of the game, that should be the same game but adding AY sound. I’m not a fan of that, because I prefer to offer the same experience in all models, but people expect AY sound in 128K models, even if the game is targeting 48K. For now this is low priority, but it shouldn’t be too difficult.

I have a few possible ideas for the game, although it doesn’t need to be necessarily a ZX Spectrum 48K game. In reality I could jump directly into making the game, without having to write any new library code, if I was using my Amstrad CPC or MSX libraries, but I still want to make a speccy game on 48K, so there’s also that!

Crash was a British magazine specialised on the ZX Spectrum home computer, that run from February 1984 to April 1992.

There were a healthy number of magazines back then, and the speccy had very good coverage with several publications dedicated to it, but Crash was one of the most popular –if not the most!– in the UK.

Crash was already back with us, to some capacity, in the form of an annual. But more recently, the same publisher has launched a bi-monthly 60 pages publication in A5: Crash Magazine.

You can buy specific issues from the publisher’s website, or subscribe via Patreon –that has the option for PDF as well–.

I’ve subscribed and read the first two numbers, and I like it very much.

Looking at the last number (Feb 2021, using the cover of the second issue of the original Crash magazine!), there are three features (Cover crackers, Crash investigates and Crash back), three articles (Simon Buttler’s screens, Dreamworld Poggie, Software house capers), all the regular sections (Editorial, Lloyd Mangram’s Forum –reader letters–, Adventure trail, Nick Robert’s playing tips, Preview and Sign off), and lots of reviews of new games!

I already liked the annuals (I have 2018 and 2019), and this new Crash keeps the good things, and builds on top of them in a shorter and more immediate format.

The reviews are nice and balanced –mostly notable games, why would you like to review a bad game when most of the new releases are free to download and play?–, with the right tone and attitude. The regular sections have a nice “back in the day” feel to them, and the articles are also a good read.

There is some coverage of the ZX Spectrum Next as well, that I must confess I’ve been mostly ignoring until now; and overall I can’t find anything to improve. I couldn’t enjoy the original magazine back in the day, but I’ve been flicking through its pages on archive.org, and this Crash Micro Action feels like a good spiritual successor.

Anyway, I know it sounds crazy that we can still play new games for our loved 8-bit machines, but I must confess that reading a new number of Crash in 2021 was totally unexpected!

Two days ago I released the source code of Castaway, a game written in C for the ZX Spectrum 48k.

I had released this game in 2016, and it was my last game using Z88DK compiler. Back then SDCC was much better, so I changed compiler, but I’m told Z88DK has improved a lot in the latest releases and it is, in fact, the recommended compiler for Z80 microcomputers. I’m too invested in SDCC at this point –in 3 different systems!–, but I really like how Z88DK is evolving.

Anyway, that may not be relevant because I doubt Castaway’s sources compile with a modern release of the compiler –although I made the effort to ensure that it compiles with the appropriate version–, but I wanted to release the source code for two reasons: I had planned to do it for a while, and I read this post by Drew DeVault: the complete guide for open sourcing video games.

May be the title of the post is a bit clickbait-y, but I found interesting that Drew shares some ideas with me:

Video games are an interesting class of software. Unlike most software, they are a creative endeavour, rather than a practical utility. Where most software calls for new features to address practical needs of their users, video games call for new features to serve the creative vision of their makers.

That’s why I think that most games don’t really work well in a open source development model: release early, release often. Who wants to play an incomplete game in version 0.1.0 to play it again in 0.2.0 because it has some new feature? Although there are exceptions to this, like for example game engines, in general I don’t see the point of open source games.

But then, why did I make Castaway open source? Because what I have done is a code dump, and not really what open source is about.

Drew explains how some open source engines have been very influential –like Id’s engines–, but what finally convinced me to do it was:

Publishing open source games is also a matter of historical preservation. Proprietary games tend to atrophy. Long after their heyday, with suitable platforms scarce and physical copies difficult to obtain, many games die a slow and quiet death, forgotten to the annals of time. Some games have overcome this by releasing their source code, making it easier for fans to port the game to new platforms and keep it alive.

This is very relevant looking at current news that Sony’s PS3, PSP, and Vita digital stores may be closing this summer, and in a world where games are “digital only” that means a lot of games will be lost. And we know how many missing in action games we have in our classic platforms, despite the huge community effort to preserve everything.

Although I don’t think my games are at risk of getting lost –I believe most, if not all, have been preserved–, there’s also some value for anyone willing to learn by reading the code, despite not being the best code (I was learning, and Z88DK had its own limitations back then that translates into a lot of includes).

So it is done. Arguably I should be doing the same for the most recent games, but it is difficult; so Castaway is also preparing me to release more current code that is more what I am today instead of what I was as gamedev about 5 years ago. We will see!