# Opening in Unity The download button on a cart. Needs a Unity project (6.3 or newer) with [OneJS](https://onejs.com/docs) installed from the Package Manager: `https://github.com/Singtaa/OneJS.git` At the project's root, where `Assets` and `ProjectSettings` are: ```bash npx ojplay add @/ ``` That is the line under the download button. It puts the cart in its own folder at the project's root, beside `Assets`, installs it, and puts a runner for it in a scene: your first build scene, or a new `Assets/Scenes/Main.unity`. Open that scene and press Play. OneJS builds the cart when the project opens, and again each time you save. With the project open in Unity, it leaves your scenes alone and says which prefab to drag in. | | | |---|---| | Your own cart | Lands as a git clone, or a submodule in a project that is a git repository. Edit, save, `git push`: the site builds it | | Somebody else's | Lands as the build they published. To change it, fork it on the site and add yours | | Private cart | `npx ojplay login` first, once per machine | | A piece of an app you have | Run the line in that app's `~` folder instead. `oj.json` lists the cart, and `import { Bolt } from "@/"` works; its art ships with your build | Your cart file does not change. ## What it writes | | | |---|---| | `/` | The cart, beside `Assets`. What `ojplay init` adds there (`package.json`, `tsconfig.json`, types) is kept out of git, so `git status` shows only your cart | | `Assets//.prefab` | A `JSRunner` that runs the cart, linked by the `name` in its `oj.json`: the thing placed in the scene | | `Assets//PanelSettings.asset` | The runner's panel settings | | `Assets/Scenes/Main.unity` | Only when the build list has no scene, and then added to it | Unity writes nothing inside the cart. It builds the cart into `Library/`, and a player build ships the cart's [files](/docs/files) under `StreamingAssets`. By hand, the same thing: `git clone https://play.onejs.com/@/.git` at the project's root (or `git submodule add` in a project that is a git repository), then add a `JSRunner`, pick the cart from the **Cart** dropdown in its inspector, and press **Set Up**. [Running a Root Cart](https://onejs.com/docs/guides/project-setup#running-a-root-cart) on onejs.com has the rest. ## Carts in `Assets//~` A OneJS older than 3.9.9 cannot run a cart from the project's root, so there `ojplay add` puts it in `Assets//~`, inside a OneJS app with OneJS's own build files around it. It keeps working there. On OneJS 3.9.11 or newer, that app's runner offers **Move to Project Root** in its inspector. It moves the cart to `/` beside `Assets` (with `git mv` when git tracks it), links the runner to the cart by name, deletes the app's built bundle, and takes out the files OneJS's setup put in the cart. A file somebody changed is left, and listed in the Console. The PanelSettings and the prefab stay. A runner in a scene that is not open still points at the app: pick the cart in its **Cart** field. ## Input `input` needs the Input System package, with **Active Input Handling** set to *Input System* or *Both*. New Unity 6 projects have it. Without it: one warning, and input stays idle. Positions from Input System **actions** are in screen space. `input.mouse` and `input.touches` are converted for you. ## What changes | | In Unity | |---|---| | [`assetUrl`](/docs/files) | The cart's own folder, or `StreamingAssets` in a build | | `mount()` | Starts its own runtime | | A [`.sl` shader](/docs/effects) | Becomes a real shader, compiled by Unity | | The control theme | Comes with you | What you gain: your own C#, all of Unity, scenes, 3D, every build target, no sandbox. ## From your own machine Every cart is a git repository, and the editor is one client of it. A new cart can start on your machine instead of the site: `ojplay new ""` writes the starter into a new repository with no account, and its first `ojplay push` makes the cart on the site, private, logging you in first if you are not. A name you already use is refused at that push, and nothing is made; rename it in `oj.json`, commit and push again. A cart already on the site clones with its address plus `.git`: a public cart needs nothing, and a private one of yours needs `npx ojplay login` once per machine first. ```bash git clone https://play.onejs.com/@/.git cd ojplay init # package.json, tsconfig.json and types, all gitignored npm install ojplay run # the cart in the site's real container, in a local Chrome git push origin main # builds on the site, and becomes what everyone plays ``` A push to `main` builds the commit on the site and, if it builds, makes it what everyone plays. The result comes back on the `remote:` lines, with the file, line and column of any compile error. The push lands either way, so the last commit that built keeps running until the next one that does. `ojplay` is a command you install once, `npm install -g ojplay` (or prefix each command with `npx`, which needs no install). It wraps the rest: `new`, `add`, `build`, `typecheck`, `run`, `test`, `status`, `push` and `runtime`, and `ojplay help` describes each one. Inside a cart that has its own ojplay in `node_modules`, it runs that one. An AI agent handed a cart should start at [agents.md](/agents.md), which the first lines of a new cart's `index.tsx` point at. The editor keeps your typing as a draft only you see, and its Push commits on top of whatever `main` holds by then, so a `git push` in between is kept: Push lists what came in, and asks which version to keep of any file both changed. Git refuses a push that is not a fast forward, so whoever is second finds out rather than winning. The site does accept a force push, and it replaces what was pushed from the editor, so pull instead.