scratch-coder

# Scratch Coder Create Scratch 3.0 projects with Python and ScratchGen. ## Setup ```bash pip install "ScratchGen~=1.1" ``` ## Quick start ```python from ScratchGen import * project = Project() sprite = project.createSprite('Cat') sprite.createScript( WhenFlagClicked(), Show(), Say('Hello!') ) project.save('hello.sb3') ``` ## Common pitfalls - Sprites are hidden by default. Call `Show()` in `WhenFlagClicked()`. - Sprites have no default costume. Add costumes via `addCostume()` or inject them after saving. - `Broadcast()` / `WhenBroadcastReceived()` use null IDs in ScratchGen. Use `ChangeVariable` on global stage variables for cross-sprite state instead. - `GetAttribute` requires ScratchGen constants, not strings: `GetAttribute(Y_POSITION, ball)`. - `Stop(ALL)` clears speech bubbles before rendering. Use a `game_over` state variable plus a dedicated message sprite. - Stage fence clamps sprites at `y = -180` to `180`. Keep detection thresholds inside the bounds. ## Stage coordinates - x: -240 to 240 - y: -180 to 180 ## Physics tips - Keep `MoveSteps(N)` <= half the target sprite's width to avoid tunneling. - For axis-aligned games, store direction as `dx`/`dy` stage variables and move with `ChangeX(Multiply(dx, speed))`. ## Save pipeline ``` project.save() -> add_costumes() -> add_monitors() ``` ## Testing ```bash python -c "import zipfile; print(zipfile.ZipFile('project.sb3').namelist())" ``` Open the file in TurboWarp to verify. ## Reference - `references/block-reference.md` — complete block reference