Variables & types
Values, mutability, primitives and vectors.
Sindri's gameplay language
Build game logic.
Keep Rust underneath.
Decay is a Rust-inspired, statically typed language made for gameplay. Learn it by building, look up exact syntax when you need it, and get back to your game.
player.decay
script Player {
@export
var speed: f32 = 220.0;
fn update(dt: f32) {
let direction = Input.axis("move_left", "move_right");
this.transform.position.x += direction * speed * dt;
}
}Start here
Learn by making things happen.
Short lessons introduce language features when a game actually needs them. Revolutionary concept, apparently.
01→
02
03
04
05
06
Your first script
Attach behaviour, expose a value, and understand the update loop.
Functions
Turn behaviour into readable, reusable pieces.
Entities & scripts
Understand where gameplay behaviour lives.
Communication
Typed script messages, events and shared state.
Put it together
Build a small playable system from the pieces.
Learn Decay / Getting started
Your first Decay script
A Decay script adds gameplay behaviour to an entity. Start with the smallest useful thing: a value you can tune in Sindri and code that runs every frame.
What you'll learn
Scripts, exported fields, typed values, functions, update, and why dt exists.
Declare a script
script Player {
@export
var speed: f32 = 220.0;
}script Player declares a gameplay script type. @export makes speed editable from Sindri instead of burying tuning values in source.
Run behaviour every frame
fn update(dt: f32) {
let direction = Input.axis("move_left", "move_right");
this.transform.position.x += direction * speed * dt;
}The engine calls update while the script is active. Multiplying movement by dt makes speed depend on time rather than frame rate.
Next lessonVariables & types →
Guided project
Make a complete game.
One project from empty scene to exported build. No mysterious starter project quietly doing half the work.
Coming next
Build a tiny arena game
Movement, enemies, collisions, health, score, events, shared state, audio, Weave UI and export, introduced because the game needs them.
15 chapters
Knowledgebase foundation in progress
Cookbook
How do I…?
Answers for when you already know enough Decay and simply need the thing on screen to behave.
Move an entity
Read input and apply frame-rate-independent movement.
Talk to another script
Use typed script references instead of property-name strings.
Keep game-wide score
Choose shared state when data belongs to the game rather than one entity.
Reference
Exact answers, quickly.
Language truth comes from Decay. Sindri host API truth comes from Sindri. This site presents it instead of inventing a third version.
Choose the right communication tool.
One particular script?Typed script reference / message
→Announce something happened?Event
→Game-wide data?Shared state