Scott T: The Blog

Digging into T7G iOS

Posted Tue, Nov 29, 2011 at 8:43pm by Scott
Tagged: games, programming, scummvm

I've been thinking about writing up this post for the last few months now but with the release of ScummVM 1.4.0 a few weeks back (which supports T7G iOS), now seems like a suitable time.

My first iOS game!

The 7th Guest for iPhone and iPad was announced mid last year and then released in December. I read around a bit at the launch and it seemed a mixed bag - three culled puzzles (including the notorious microscope puzzle), high framerates for most videos, but a good large dose of nostalgia for many people.

Back in April I was able to borrow a friends iPhone, and so was finally able to test out the port for myself. Though it played fluidly, it was a little rough around the edges - the music was a little flat (admittedly this is personal preference), the cursor mapping just above the finger was a little awkward for some puzzles, high-speed animations included all the 'teeth' events which took away from the atmosphere (and caused out-of-sync music). Interestingly, the port also suffered the same problem as the Windows interpreter (see ScummVM bug #2831041) though not too surprising given the Windows release source was likely used as the reference. Similarly, the cake puzzle bug also still exists.

After the playthrough, the next step was to obviously look under the hood. After extracting the app archive and digging down into the folder heirarchy, it turns out almost all the original game datafiles were present, completely untouched (including the original introduction and credits - both of which were replaced in the port). Data-wise, the largest change was the removal of XMIDI music in favour of AAC.

AAC powered music!

Work then began on the required changes to support the game - clone2727 mostly worked on the AAC decoder (as part of extending the QuickTime code) while I added the necessary changes to handle and load the music resources as well as a config file option to run the game at faster game speeds (add t7g_speed=tweaked in the ScummVM config file for faster walking/puzzles but normal cutscenes and supernatural events, t7g_speed=im_an_ios for all non-cutscene videos sped up).

Stauf is back for more microscopic action

In the end, it was a relatively straight-forward process to add support for the game. The missing puzzles are also back as the required game scripts were never removed. Best of all - this provides an easy way (if you have an iTunes account) to grab T7G but play it on whatever platform you desire :)


Hahah I've been playing T7G on my Droid for some time now... It's neat to see that this is probably the first time someone can play an iOS app on an Android phone!

I've always wondered if there's any further progress on the Groovie engine support... Will I be able to play 11H and Uncle Henry's on my Droid before iOS people do? ;)

Posted Wed, Nov 30, 2011 at 3:46am by Ellmann

Hahaha never mind... I used to subscribe to Planet ScummVM, which did not contain all of your posts...

Just found some interesting stuff on the programming tags... Not bad at all. Great work! =]

Posted Wed, Nov 30, 2011 at 4:11am by Ellmann

@Ellmann: It'd be nice to see 11H and Uncle Henry at some point - Trilobyte announced they've had to shelve their iOS port for a while which gives me more time. Unfortunately I'm having issues with time myself... Hopefully one day :P

Posted Wed, Nov 30, 2011 at 8:06am by Scott

@Scott: Just stop playing Skyrim, you'll have plenty of time :P

Posted Fri, Dec 02, 2011 at 12:04pm by clone2727

@clone2727: Awww. You're no fun :(

Posted Sun, Dec 04, 2011 at 11:45am by Scott

And out of curiosity... I wasn't aware the microscope puzzle wasn't available on the iOS version (yay, I got a better version on my Android! :p). What other puzzles aren't available?
Didn't they include the microscope puzzle for the same reasons scummvm had in the beggining (afaik it was some deal with Stauf's AI).
Because... They released a microscope puzzle app... Couldn't they add the ai logic to the interpreter they used on t7g?

Posted Tue, Dec 06, 2011 at 3:37am by Ellmann

@Ellmann: Microscope, piano, and the knife/pentagram puzzles were cut. From memory, their justification was the need to reprogram the AI for the microscope puzzle, while the piano and knife puzzles were removed due to their small size relative to the screen. I guess they could have added the logic to the interpreter, but then there would have been less of a market for the standalone app.

Posted Fri, Dec 09, 2011 at 9:30am by Scott

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