This week was quite busy and eventful! I had my keymapper implementations for the Supernova and Voyeur engines successfully merged, and I also completed keymapper support for Titanic and Tetraedge. In addition, I took on an extra task to help normalize all keymapper action descriptions across the project.
Titanic: The Most Challenging Engine So Far
Out of all the engines I’ve worked on so far, Titanic has definitely been the most complex.
Implementing the keymapper took me about four days, most of which were spent trying to understand how input was being handled. Unlike other engines, Titanic processes input through a system of “messages.” Key presses are encapsulated in these messages and passed around to various components that need to handle input. This indirect approach made the input flow harder to trace.
Even though I’m still not 100% confident I fully understand every detail of the mechanism, I eventually got the keymapper working by mimicking how raw keycodes were originally processed. After two days of reading and experimenting, things finally started to click — and from that point on, it was just a matter of replacing keycodes with action-based mappings and writing the action bindings.
Tetraedge: The Easiest One Yet
In contrast to Titanic, Tetraedge was a breeze. The engine only uses three keys and mouse input, so I was able to wrap up the keymapper integration in half a day. Always nice to have a quick win!
Action Label Normalization: A Multilingual Cleanup
ScummVM’s GUI is actively translated into many languages by the community using Weblate. Weblate automatically picks up strings that are explicitly marked for translation in the code.
To reduce the translators’ workload, it’s important that identical strings are reused consistently across the codebase. Weblate treats strings with even minor differences — like different capitalization — as separate entries. Unfortunately, over the years, different contributors have used varying styles (sentence case, title case, etc.) for keymapper action descriptions.
To help streamline translations, I went through and normalized 1100+ action labels to follow sentence capitalization. The task itself wasn’t difficult, but it was quite repetitive. Fortunately, sev helped by providing a git grep and awk-based workflow that made identifying and editing the labels much faster. With that in place, I was able to get through the normalization process much more efficiently.
Wrapping Up
This week, I:
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Got my Supernova and Voyeur keymapper PRs merged 🎉
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Implemented full keymapper support for Titanic (the hardest one so far)
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Added keymapper support to Tetraedge (the easiest one yet)
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Normalized 1100+ keymapper action labels for consistent translations across the GUI
Next week, I plan to keep the momentum going and tackle keymapper support for more engines. With each engine, I’m getting a better understanding of the diverse input systems in ScummVM—and figuring out how to adapt the keymapper to each one’s quirks.