Introduction
During this week of GSoC, I opened PRs for adding text-to-speech to ADL and Parallaction. I thought that these engines would take me longer than they did, but neither of them were particularly challenging, which was a pleasant surprise.
ADL
I spent the beginning of this week finishing TTS for ADL. Fortunately, it needed very little additional work from last week: I only needed to add TTS to a few extra key presses and clean up the text, primarily by removing dashes that could interfere with voicing. Since ADL’s games are so simple, there wasn’t much to do with this engine, and I was able to make a PR early in the week.
Parallaction
After ADL, I worked on Parallaction, which has a level of complexity that is comparable to that of other engines I’ve worked with. To begin, Parallaction’s text is displayed through methods that are only called once, instead of every frame like most of the engines I’ve worked on. As a result, I didn’t have to track the previously said text for this engine, and it was rather simple to voice the text – although in certain cases, such as labels, I had to store the text to be voiced later, as all possible labels are initialized at once, and voicing them upon initialization would result in a great amount of invisible text being voiced. I was glad to find that voicing the text in these methods covered almost all instances of text, including dialogue options when hovered over.
Nonetheless, Parallaction did have a few exceptions to consider, mainly in the form of its credits and introduction. Most of the text in the introductory cutscene and the credits is in the form of an image, which required finding a good place to detect when these images are rendered. For example, the second and third opening credit lines appear after an animation plays, unlike the first line, which appears the instant the location switches. Therefore, I opted to voice this text in the on instruction opcode, as it is executed when these animations finish. A similar problem emerges with the end credits, which are in the form of images that slowly scroll upward. Trying to voice all of them the instant the credits begin results in the TTS speaking too quickly and being poorly synced with the actual credits. To fix this issue, I found that the instruction opcode inc is executed roughly when another credit moves onto screen. Thus, after voicing the first few credits at once – since inc isn’t executed for these – I voiced the credits one at a time in this opcode, resulting in much cleaner voicing. Finally, I resolved another syncing problem where the test results, displayed after picking a character, disappear too quickly for the TTS to keep up by delaying the loop that controls the location change while TTS is speaking. A similar strategy was used for some of the opening credits. The result is TTS that is better synced to the text for certain images and situations.
Another interesting task for Parallaction was switching voices for each character, which was doable because each character is differentiated by their .talk file. In most cases, a simple array with each file name was enough for switching voices during dialogue. However, some dialogue interactions, such as the one between all three playable characters at the end of the game, have more than one character per .talk file, differentiated by the mood value. This was resolved by updating the array to have extra entries, and adding the mood as an offset to the index for these special cases. Beyond that, the TTS voice needed to be switched when exiting a slide, showing a location comment (which I decided to use an extra “narrator” voice for), and switching characters, allowing for more dynamic character voicing.
Ultimately, Parallaction was an entertaining engine to add TTS to. It was mostly simple, with its exceptions – such as text in the form of an image, unique means of selecting a language, and password inputs – being not too hard to handle. Nonetheless, it’s currently only been tested with Nippon Safes, Inc. From the code, the Big Red Adventure seems to handle text similarly, allowing me to add tentative TTS to it, but I’m uncertain if it will work as well. Some translations also need verification.
Conclusion
I think that this week of GSoC was fairly successful, with PRs opened for adding TTS to ADL and Parallaction. ADL was easy, while Parallaction had very few surprises, making them both simpler than I expected. Next week, I’ll be working on adding TTS to Prince, which I’m looking forward to exploring.