Below is a photograph of PipePanic running on a real ZX81 at the National Museum of Computing at Bletchley Park, England (photo © Shaun Bebbington and used with permission).

The game is running in demo mode (attract mode) and an early draft of the cassette inlay can be seen on top of the television (go here for the latest version of the inlay).

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After a swelteringly hot couple of months I've managed to complete my first machine code ZX81 game. It's one I've written before, firstly in JavaScript and then C+SDL and I have improved the engine by animating the fill with greater resolution; ironic considering the ZX81's display is 32x24! The only major change I had to make was to the board size: reduced from 10x10 to 8x8.

Pipe pieces are placed using a cursor and so I've designed the menus to operate using the same system. What you can't see from the screenshots below is that I've implemented a random transitional fade between screens which often gives the appearance of morphing.

The engine -- written from scratch -- abstracts the keyboard hardware by maintaining an event generating and queuing subsystem which supports per-action key repeating, event polling and user event pushing (similar to SDL). Some useful functions include blink_register/unregister that manage blinking parts of the screen, and string_write that accepts embedded formatting characters for source data compression/expansion and write position direction. These things I have carefully constructed to be reusable and to speed-up further game development.

PipePanic is part of the sz81 project and can be downloaded here .

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I'm now going to take a short break from developing sz81 because I'd like to explore cross-assembling ZX81 machine code programs on my desktop computer and so I've created an assembly template for use with the *NIX cross-assembler z80-asm .

[UPDATE 2010-07-14] The template is now part of the sz81 project and can be located here .

I have a definite idea for a simple but addictive game that I'd like to realise on the ZX81 since it would be the ideal platform for it, and there's a possibility I may write a classic game that I'm already familiar with.

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The project's really coming along now and I've just added some important runtime options. A save state system will be the next feature to be implemented and then the command line interface is going to be re-engineered to present some static options graphically at the start.

I'm still using my aging Sharp Zaurus SL-5500 and so I always create a package for this device (supports the later VGA models too) and I'm happy to see that several people so far have managed to find it :) I've just found out that the OESF forums are back online (I thought they were gone forever!) and so I'll post this news on there too.

More details here .

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Changes:

• Converted non OSS timing to use a more portable SDL timer.
• Added an icon based control bar with several useful options.
• Added ZX bitmap fonts and a bitmap font engine for future use within the GUI.
• Added Chris Young's AmigaOS4 specific code.

More details here .

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Changes:

• Added mouse/stylus interactivity to the keyboard with adjustable opacity and autohide on newline.

More details here .

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Changes:

• Added new keyboard images.
• The renderer now centres the emulator regardless of resolution.

More details here .

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sz81 is an SDL port of Russell Marks's z81/xz81 ZX80/81 emulator.

Additional features over z81/xz81 :-

• Runtime switchable scaling between 320x240, 640x480 and 960x720
• Runtime toggling between a window and fullscreen on supported platforms
• Support for portrait orientated screens 240x320 and 480x640
• User-definable (actually currently developer-definable) keys
• Joystick to keyboard remapping (the GP2X build uses this feature)
• Maximum porting potential since it only requires SDL

See the project page for more information and downloads. Since I want it to integrate with the existing z81/xz81 project I'm maintaining it as a diff patch which the user is required to apply (instructions provided).

The port is complete now but I may add some enhancements for portable devices later (my SDL code has complete control over the emulator and it's begging for additional functionality). It includes Makefiles for the Sharp Zaurus and GPH GP2X and can be successfully built for these devices if you have the necessary SDKs installed.

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GNU Robbo 0.65-1 for the Sharp ROM Zaurus has been released. Please visit the GNU Robbo website for downloads.

For more information about this specific port you can visit this thread on the OESF forums.

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The GNU Robbo Team has released GNU Robbo 0.64 which includes the mouse/stylus support that I recently completed and finally sound and sound skin support implemented by a new member of the team - neurocyp. There are also 19 additional level packs converted from either Robbo or Robbo Konstructor games which brings the current level total to 975!

For the complete changelog, screenshots and downloads please visit the GNU Robbo website .

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ChangeLog:

• Fixed a bug that caused RbVBA to crash with a NilObjectException.
• Fixed bugs associated with folder and file selection dialogs.
• Rebuilt RbVBA's source and binary packages using REALbasic2009r4.

Please note: REALbasic is not required for the binary, but if you want to compile the source yourself, download the trial version and then ask them for a free open source licence and they'll supply you with one that unlocks the Personal Edition.

More details here.

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When I was younger I had a Sinclair ZX81 but I never learnt how to write machine code programs, but now I know how because I've read this wonderful book by Toni Baker called Mastering Machine Code on Your ZX81 or ZX80. To cut a long story short I've transcribed it from a freely downloadable 22MB PDF of scanned pages i.e. images to less than 1MB of HTML, excellent for reading with portable devices. And I've coded and included all the example programs too! So, what are you waiting for, get reading :)

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Not being something I've tackled before on Linux, I thought I'd attempt to get some type of interaction going between a bash script and a running program written in C, and somebody suggested I might like to research named pipes (FIFOs).

On searching the Internet I found FIFO examples for bash to bash and C program to C program communication, but not between a bash script and a C program, and so I came up with something quite interesting that although I currently don't have the time to develop it any further, might be of use to other people wanting to do a similar thing.

I've posted the code on my website here so that people can find it via search engines.

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Willem-Jan de Hoog has been busily updating his Nokia N8x0 (OS2008) port of GNU Robbo to include the mouse/stylus support that was recently added to SVN. Additionally his port also supports the wii remote! More information is available on Willem-Jan's website and maemo.org .

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In my youth, my friend's younger brother bought Bruce Lee for his 48K Spectrum and we'd play 2-player games, one person being Bruce and the other Green Yamo. Back then I remember not only the two player experience being fun but also the game itself being an impressive Spectrum title. Nowadays like many people I play older games via emulation and I recently played this through using GP2Xpectrum on my GP2X .

This game has aged really well, still looking and playing great 25 years later. You play as Bruce Lee, collecting lanterns which remove barriers to additional screens and there are about 20 screens in all. Following you throughout the game are the Ninja with a stick and the Green Yamo who looks like a big fat teddy bear, and you trade flying kicks and punches with them until you knock them out only to reappear after a short time.

What I like about this game is that your character is very controllable, the graphics are pretty and atmospheric and the screens are well designed. I was surprised by how quickly I completed it but it was enjoyable all the way through and it didn't become just another game I got frustrated and bored with. I can really recommend hunting this game down for your favourite home computer emulator.

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I bought this game when it was released several years ago but didn't get very far with it. It's not that I didn't like it, it's just that I used to buy lots of games and I'd move onto something else. I later played Gothic 2 through to the end -- a fantastic experience -- and this is the reason why I returned to the original.

Wow, this game is such an amazing piece of work! It's so engrossing that I couldn't wait to load it up at the end of the day and immerse myself back into the wonderful Gothic world. The world is huge and varied, initially with parts inaccessible mainly due to your character not having attained the necessary skills to confront the wild animals that roam them, but also because you do not have the authority or social standing to enter them. None the less, you will be able to visit and explore your first port of call -- the Old Camp, and then the New Camp and Swamp Camp. The Old Camp is populated by morally better people than the New Camp and the Swamp Camp is populated by a religious sect who spend a lot of time smoking different types of weed. On top of this, the Magicians of Fire share the Old Camp and the Magicians of Water the New Camp. You will eventually have to choose which camp to join as a soldier, but afterwards you can change to the relevant magic circle.

There is so much depth to this game: different camps of different people, many types of animals and monsters, wild plants and fruits to utilise, magical objects to discover, a huge choice of weaponry and a favourite of mine -- transformation scrolls. It's possible to transform into an animal or monster so that you can explore parts of the map you may not have attained the experience to enter. And at some point you will see and eventually confront the Orcs.

A truly monumental gaming experience, and the sequel Gothic 2 is equally as brilliant. Many thanks Piranha Bytes .

You can view the English introductory video on YouTube here http://www.youtube.com/watch?v=rRjNsWFetRo

Below are some early screenshots of the game with descriptive filenames. There are many more fantastical parts that I don't want to spoil.

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I want to talk about a few games I've played recently that were good enough to keep my attention till the end.

First up then is the Sims - Bustin' Out on GBA. I resisted the Sims on the PC because I thought it was dumbing down the market and so all all of the games I ignored until I tried this. I think it's technically very impressive for a 240x160 handheld device. I found completing the tasks to reach the next level addictive, the mini games mostly fun -- but then they are jobs -- and you earn money which you can spend on expensive objects for your house that you don't need :) I've played so many games where I've reached a particularly boring or tedious part and I've left it, that it's nice to find one that keeps my interest all the way through. Many thanks Griptonite Games .

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I've been busy adding an event based rectangular object engine to GNU Robbo to accommodate a level designer and mouse/stylus controls. The game now entirely supports the use of a mouse or stylus and I've been testing it on my Sharp Zaurus and found it to be an effective alternative way to play. Having tried different in-game pointer control layouts, I decided to use a cross centred on Robbo with a toggleable centre button for shooting that also shoots by dragging from the centre outwards. It didn't take much testing before I chose this method; it felt right from the start and doesn't require the user to focus elsewhere on the screen.

The above in-game directional pad and toolbar are accessible to all platforms that support pointer input and require a simple click of the screen to enable.

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Today I released the initial stable version of an event/object based SDL engine that I started about a year ago. To assist in its development I used it to write a version of Tetravex and an ASCII text file reader which are both good examples of what can be achieved with it. I wrote it because I was tiring of writing the same things over and over in my C+SDL projects and thought it was about time I offloaded these repetitive tasks to an engine. Despite the low version number the engine is almost complete with only an object navigation mode using the cursor events and the command-line subsystem remaining to be implemented. The ASCII text reader demo is finished and the Tetravex game only requires the completion of the high score table.

Following are some images from this release plus several more available here .

Freshmeat project page: http://freshmeat.net/projects/eng
Sourceforge project page: http://sourceforge.net/projects/eng
Launchpad project page: https://launchpad.net/eng

[UPDATE 2009-05-12] I have started to document the engine on the project's Sourceforge wiki .

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A couple of days ago GNU Robbo 0.62 was released with some additional translations, pixmap fonts and a Sharp Zaurus IPK . I'm now adding mouse/stylus support along with a basic object engine that manages painted/unpainted fixed/draggable parent/child rectangles that receive left-click hits. I say "basic" because within the last year I've written an event/object based SDL engine with all sorts of bells and whistles (more on this later) and I'm going to introduce a simplified version of it into GNU Robbo. This is required to accommodate the level designer and to add a mouse/stylus game input area for touchscreen handheld devices.

A chap called Willem-Jan de Hoog contacted the GNU Robbo team and mentioned he'd recently created a Maemo (OS2008) port based on version 0.57. Because his Nokia N800 model only has a navigational pad and stylus input he created an on-screen stylus control pad which you can see in the following image. It was he who requested this feature be implemented in the GNU Robbo project and it will be a piece of cake once my mouse/object code is in.

[UPDATE 2009-03-23] Willem-Jan has been busy adding his stylus control pad support to the latest version of GNU Robbo and it's looking really nice. Take a look at the recent screenshot on the right.

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I've finally developed GNU Robbo to a more complete state although sound and a level designer remain to be done. There are Linux, Win32 and GP2X packages currently available with a Sharp Zaurus port to follow.

For more information please visit the official GNU Robbo website here -> http://gnurobbo.sourceforge.net/

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More Tronic skin updates; only eight sprites remaining now.

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I've been working on the new Tronic skin and I'm very pleased with how it's developing.

There's an updated capsule and crates, a screw, teleport, question mark (for random items), key, bomb, raygun and cratered planet.

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I've finally got around to creating a modern original website with a blog. Now I can share my thoughts and rants with the world and the world can respond!

So what's new?

• The inclusion of my original JavaScript version of Pipepanic (source available).
• Repackaged downloads of the online games if you're interested in Flash/JavaScript game development.

I have further developed some existing projects and created a few new ones which will be uploaded in the very near future (details to follow). For now here's a screenshot of the near complete GNU Robbo 0.60 graphical makeover :-

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Version 0.0.4 released.

• CPU - added 92 instructions.
• Virtual Keyboard :-
• Added a virtual keyboard (vkeyb).
• ROM :-
• INT 9
• PIT :-
• Renamed the timer to Programmable Interval Timer.
• PIC :-
• Added a Programmable Interrupt Controller to manage external interrupts.
• Keyboard :-
• INT 16 Service 00 Read Next Keyboard Character
• DOS :-
• INT 20 Program Terminate
• INT 21 Function 3C Create File
• Video :-
• Fixed the video refresh timer @ 20ms (50Hz).
• Overall :-
• Optimised and performance tested.
• It's now possible to specify a program to emulate via the command line.
• Additional command line options include :-
• Video dimensions, frameskip and fullscreen
• CPU delay initial value and increment
• A simple DOS VGA freeware Pac-Man game (included and shown here) can be emulated.

Version 0701-2 released.

• Updated the build system only.

Version 0701-1 released.

I've been unable to work on any of my projects since January 2007 (my development system requires reassembling) but I intend to get back into the swing of things very soon. I did manage to get an old DOS VGA game emulated perfectly with working virtual keyboard (see image below) but I didn't get a chance to package and upload it. I can report though that it's very fast on the Sharp Zaurus SL-5500 so things are looking very good indeed.

Version 0.0.3 released.

• CPU - added 53 instructions.
• Timer :-
• Channel 0 timer - system (clock-tick) timer @ 20ms
• Keyboard :-
• INT 16 Service 01 Report Whether Character Ready
• ROM :-
• ROM and ROM BIOS
• Interrupt vector table
• INT 8
• INT 1A Service 00 Time-of-Day Services
• INT 1C (triggered by INT 8)
• DOS :-
• INT 21 Function 42 Move File Pointer
• INT 21 Function 48 Allocate Memory Block has been rewritten
• INT 21 Function 49 Free Memory Block has been rewritten
• INT 21 Function 4A Resize Memory Block has been rewritten
• Video :-
• Video mode 13 VGA 256 colours
• Video refresh timer @ 30ms (33fps)
• INT 10 Service 10 Colour Palette Interface
• RAM :-
• Read and write dwords
• Disassembler :-
• Has been considerably restructured.
• RAM read/writes can be dumped to the terminal.

Version 0.0.2 released.

• CPU - added 46 instructions.
• DOS :-
• INT 21 Function 02 Character Output
• INT 21 Function 09 String Output
• INT 21 Function 4C Terminate With Return Code
• Video :-
• INT 10 Service 00 Set Video Mode
• INT 10 Service 1A Read/Write Display Combination Code
• Disassembler :-
• Improved the memory dumper.
• Overall :-
• Optimised and performance tested.

Version 0.0.1 released.

• CPU - added 39 instructions.
• DOS :-
• An initial memory block header structure is set-up in the DOS memory array.
• A COM file can be loaded into 'memory'.
• INT 21 Function 30 Get DOS Version Number
• INT 21 Function 3D Open Handle
• INT 21 Function 3E Close Handle
• INT 21 Function 3F Read from File or Device
• INT 21 Function 48 Allocate Memory Block
• INT 21 Function 49 Free Memory Block
• INT 21 Function 4A Resize Memory Block
• Disassembler :-
• Register dump
• Assembly output
• RAM (memory array) dump

Version 0.3.1 released.

• Now showing full path to current ROM above games list to aid identification.
• Added a 'not equal' comparison option to the unknown value Trainer search method.

Version 0.1.3 released.

• Shuffled pipes and preview pieces are reinitialised for each game.
• Created a Zaurus ARM binary tarball in addition to the ipk.
• Updated the tools for building the Zaurus version.

Version 0.1.2 released.

• Removed -Dmain=SDL_main from the Linux makefile.

Version 0.1.1 released.

• Updated the tools for building the Zaurus version.

Version 0.1.0 released.

There were some corrupt files on this site so I have uploaded fresh copies.

Version 0.3.0 released.

• Added a save state Trainer for creating cheats for gba, gbc and gb.
• Added an option to RbVBArc for specifying a folder to accommodate the individual cheat files.
• Listboxes now sort properly matching the user's selection.
• Currently selected game now displayed in window title bar.

Version 0.2.0 released.

• Added support for .gz (also .z) and .zip ROMs.
• It's now possible to select the QJoyPad "[NO LAYOUT]" layout.
• Many other insignificant alterations.

Version 0.1.1 released.

Version 0.1.0 released.

Version 0.57.041 released.

• Added an option to the desktop file to disable magnification on C Series Zaurii. This does not affect the operation of the SL-XX00 models.
• Added an enhancement ipk by Greg2 . This ipk creates an additional desktop file that starts GNU Robbo in 320x240 landscape mode for Zaurus SL-5X00 models.

Version 0.57.040 released.

• 35 new levels added, new wall graphics, game area resizing for Zaurus VGA models.

Version 0.57.03 released.

• The game now works on the Zaurus C Series.

Version 0.57.02 released.

• The game is now a complete conversion, although I still want to add stylus support in the near future.

Version 0.57.01 released.