Knock Knock 🎃

The town is overrun with monsters! And kids... sometimes they’re hard to tell apart. But it would be a sin to deny kids their well-earned trick-or-treat candy. Inspired by the classic Halloween tradition, I wanted to create a simple loop where you give candy to the kids and, hopefully, refuse any monster that tries to wriggle its way inside.

You have tonight’s list, with a photo of every child who’s coming. Someone knocks and gives a name. Look through the peephole, switch on the porch light, wave, and compare them with the photo. A real child matches it exactly; a monster is always wrong in one way you can check, and later nights add signs like a shadow that won’t wave back. I made a full post detailing the process on my website: https://www.sagitsoftware.com/projects/knock-knock/

Built with the Rive CLI and GPU Canvas, plus Scripting, Data Binding and a State Machine:

• Rive CLI: the whole scene is RML, written with a coding agent and built, previewed and tested from the terminal: 15 rule tests and 62 scripted playthroughs, each with its own capture. • GPU Canvas (WGSL): six shaders. They draw the porch under the lamp with 2.5D-lit characters and their shadows, raymarched ground mist that the porch posts and visitor cut shadows through, moths and leaves, the moon, and a fisheye peephole lens with colour fringing and breath that fogs the glass. • Scripting (Luau): the rules, the seeded nights and every cut-out character, drawn as vectors in script. • Data Binding and State Machine: a view model for the game and one for each visitor, and listeners that route every control into the game.

Play it: https://knock-knock-t9a870.rive.to/?fit=contain

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