Thread by @anastasiaopara

This month I finally convinced myself to tackle the undo-redo system since it was becoming a premonition of a technical debt👀

And of course I decided to make it animated. How hard can it be, right!? 😂 [1/10]

#screenshotsaturday #indiegamedev #rustlang 🦀 #procgen #bevyengine

[2/10] Undo is essential for this game to stay playful and relaxing: if you misclick, a cat jumps on the keyboard, or you simply change your mind, it should always be easy to go back.

I had been scheming an undo system for a while, and now was the time to roll up my sleeves 💪

[3/10] Undo-redo for terrain and paths was pretty straightforward. Since the interactions between systems are procedural, a lot of animation is happening for free 😎 For ex, arches appearing where paths cross walls, stones arranging along a path, or walls sticking to the ground

[4/10] The clip above is undoing-redoing a single terrain edit, and the one below is undoing-redoing a single path stroke.

[5/10] Undo for walls, however, turned into one of the most intricate bits of software engineering I've ever had to do 😅 A single eraser stroke can have many possible outcomes - a wall is split multiple times, erased from different sides, deleted, or any combination of those.

[6/10] I ended up writing a compiler for these events into a smaller number of lower-level operations that can be sanely maintained and replayed 🤓

Now, if you split a wall when erasing, undo will play the expected merging animation 🙌 No new specific case handling required!

[7/10] Originally, I wasn't even planning to add animations 😮 This month was only about undo-redo. But mid-way through, I realized that if I "just" added animations, I could extend undo-redo into a replay system, letting you watch your build recreated from scratch 🤩

[8/10] Being a huge fan of time lapses made by the Sims community, and the time lapse feature in Procreate, I felt that it would resonate with the vibe of my game ✨

Et voilà! I can now replay this small "Thank you" scene, hehe 😊

[9/10] Aaand that's all for the May update~ thank you for reading!

And huge big mountainous thank you @h3r2tic for feedback, brainstorms and being my editor for this post 🤗🙇‍♀️💖

[10/10] PS: if you'd like to receive these updates in your mailbox, I have a newsletter 💌tinyurl.com/2p8u9rzp

🤔 I should probably put this link somewhere in my bio so I don't need to keep linking it every time 😅