Sunday, July 16, 2023

Tut-Tut: Tomb Raiding on the Vic-20

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Tut-Tut Concept Art

A New Version of a Modern Retro Classic

Given the resounding success of my little game of Tut-Tut on platforms such as ZX Spectrum, ZX81, Jupiter ACE, and the commendable port by Tynemouth Software's Dave Curran to the Commodore PET, it was an inevitable progression to broaden the game's horizons and introduce it to the illustrious Vic-20, the "Wonder Computer of the 1980s."

New to Tut-Tut? What's this Game About?

As the digging season of 1921 draws to a close in Egypt's Valley of the Kings, it becomes evident that your excavations have yielded disappointing results. Despite your ardent efforts, no traces of the fabled and elusive Pharaohs' tombs have been uncovered. However, as the final weeks approach, intriguing rumours begin to circulate, recounting chilling accounts of vengeful mummies exacting retribution upon local would-be tomb raiders.

These wild stories, though tinged with the supernatural and curses, cannot be ignored. As an Egyptologist and daring adventurer, you find yourself presented with concrete leads and irresistible opportunities. The allure of uncovering long-lost secrets and ancient treasures proves too tempting to resist, even in the face of ominous tales of wrathful spirits.

Tut-Tut Vic20 Screen Shots
Screen Shots from the Vic-20 version of TuT-TuT

Now, on the cusp of a new expedition, you stand poised to delve into the unknown depths of the Valley of the Kings, ready to face the mysteries and potential dangers that lie ahead. Will you emerge unscathed from the clutches of ancient curses, or will the vengeful spirits lurking in the shadows prove to be more than mere legends? The answers await, as you embark on a daring quest that will test your courage, knowledge, and perhaps even your beliefs.

Prepare to embark on a journey like no other as Tut-Tut takes you on an adventure through the treacherous Egyptian tombs, with its visually stunning colour scheme and a myriad of intricately woven graphic tile sets that bring the ancient world to life before your very eyes.

The Making of the Vic-20 Version  

Tut-Tut initially originated as a BASIC type-in game, designed specifically for the ZX Spectrum and published in Paleotronic Magazine. Further versions of the game for the ZX81, Enhanced 2020 Spectrum Edition and Jupiter Ace, the latest version was one ported to the Commodore PET by Dave Curran. All varieties have all kept the core structure and mechanics as outlined there.

After witnessing the success of Dave's PET version, I couldn't help but ponder the possibility of bringing Tut-Tut to the Vic-20. While considering the similarities between the two machines, I became aware of the numerous disparities that needed to be addressed, particularly in terms of screen real-estate and the Vic-20's unconventional memory management scheme. Luckily i raised the conversion idea with Dave, and he was up to a joint challenge, as I'm in no way sure I'd have got there without our joint efforts.

Screen Real-Estate and Luck by Design

Due to Tut-Tut's origin as a ZX BASIC game, one that need to run quickly, lead to the adoption of a 26x17 character grid for the game board layout (excluding score bars etc). The ZX Spectrum's character resolution is 32x24, constraining the board size to a smaller grid made for more time efficient code in the very orriginal ZX BASIC version. These dimensions sunsiquently stuck for all future conversions.

However, while the grid size was suitable for the ZX line, it posed a challenge when porting Tut-Tut to the Vic-20. Those familiar with the Vic-20 immediately noticed the issue: the Vic-20's screen width is only 22 characters wide (and 23 high). This presented a hurdle that needed to be addressed in order to adapt the game for the Vic-20.

A possible solution could have been to reconfigure the game's levels to fit within the Vic-20's 22x23 screen limitations. This would have been easily achievable code wise, but level design wise it would come at a cost to the overall feel and immersion. A particular issue, as the existing levels are heavily constructed around the games mechanics and already small(ish) screen size.

Tut-Tut Vic20 Screen Shots / PAL vs NTSC Geometry
PAL vs NTSC Geometry Comparison

As luck would have it, the Vic-20's screen sizes can be redefined to an extent. Values in memory location 36864 to 36867 can be POKED to set screen geometry and centring. The results of doing so yielded just the right amount screen width to fit the existing level structure.

Yet another obstacle presented itself: the disparities in screen geometry between PAL and NTSC standards. NTSC, in particular, occupies a wider physical width on a display (not pixels) compared to PAL. However, by a stroke of luck, the constraints imposed by the level width inadvertently resulted in an image that delicately brushes the very edge of an NTSC display. This serendipitous alignment allowed Tut-Tut to make the most of the available screen space on both PAL and NTSC systems.

Graphics Updates

The Vic-20 is perhaps renowned for its vibrant and colourful display, you'd think this would be directly comparable to the ZX Spectrum in terms of its rich palette. However, an intriguing aspect arises when considering the variation in colour appearance based on factors such as the age, make, and region (PAL/NTSC) of the Vic Chip utilised on any given machine. Then there is the screen fuzziness / blurriness, which again varies. 

The diversity in colour appearance on different Vic-20 machines prompted us to reevaluate tile design and colour choices for Tut-Tut. In the Spectrum version, the game employed various palettes that cycled based on the level number, creating a dynamic and ever-changing visual experience. However, for the Vic-20 version, we've opted for a different approach. Instead of cycling palettes, we focused on expanding the selection of available thematic tiles while exercising tighter control over the colour schemes. (A good approach, and If I hadn't mentioned it, would probably gone unnoticed.)

We're pretty confident we reached the required level of ancient Egyptian cinematic charm / ham.

Memory for Mummies?

Another challenge we faced was determining how much memory we could allocate to the game on the Vic-20. By default, the Vic-20 only had a modest 3k of onboard memory, which was insufficient to accommodate even the most streamlined versions of Tut. The issue was further compounded by the lack of a standardised expansion memory layout and location of that memory on a Vic-20. This variability made it difficult to rely on expanded memory for larger games, often leading to the reliance on cartridges for larger game titles.

Ultimately, we proceeded with the assumption that modern enthusiasts would likely possess a contemporary memory solution, such as the Penultimate+, offering a generous 32k of memory. This assumption gave us the confidence that the game could be released on cassette. Little did we know at the time of developing the game that Tut-Tut would eventually become a pack-in title on the Penultimate+2 Cart from

Pharaohs' (Pen)Ultimate Enhancements

The Vic-20 version of Tut-Tut comes packed with all 36 levels from the ZX Spectrum 2020 Edition. In addition, we have incorporated 6 exciting new levels (bringing the total to 40) that are carefully integrated throughout the game, providing fresh challenges and surprises.

We have also included the convenient pause option from the PET version, allowing intrepid Archaeologists to take much needed meal and rest breaks. Furthermore, one of the most highly requested features we have implemented is the inclusion of level codes: Enter specific codes to access the harder levels previously reached.

All very good reasons to call this Vic-20 version, the Ultimate Tut-Tut.

Playing Vic20 Tut-Tut with the Peultimate+2 Cartridge
Playing Tut-Tut Vic-20 as included on the Penultimate+2 Cart

Special Thanks

I Can't end this post without thanking Dave Curran for sharing in the creation of the Vic-20 conversion, he'd paved much of the ground work during his PET efforts.

Additionally, thanks very much to Rob Hull for including the game in the Penultimate+2 games lineup. Very happy indeed to have it listed alongside the other TFW8b titles.

Fancey Delving Deeper into the Vic-20 Conversion?

Further Readings  unraveling the mysteries of Tut-Tut Tomb's and the Vic-20 conversion are now available on the Illustrious Tynemouth Software Blog.

Raid the Pyramids for a Copy of TuT-TuT

Commodore Vic-20

Commodore PET

ZX81 Versions

ZX Spectrum Versions

Jupiter Ace

TRS80 MC-10

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