# Ebiten
Ship Ebiten games to the web with Go's built-in js/wasm target.
Source: https://docs.wavedash.com/engines/ebiten
[Ebiten](https://ebitengine.org/) runs on any platform Go runs on, including the browser via `GOOS=js GOARCH=wasm`. Ebiten handles canvas creation and the game loop, so you just write `Update`/`Draw`/`Layout` and call `ebiten.RunGame`.
## Setup
The Go toolchain includes the `js/wasm` target out of the box. No extra install.
```bash
GOOS=js GOARCH=wasm go build -ldflags="-s -w" -o build/game.wasm .
```
You also need the `wasm_exec.js` shim that ships with your Go install:
```bash
cp "$(go env GOROOT)/lib/wasm/wasm_exec.js" build/wasm_exec.js
# (older Go versions keep it under misc/wasm/)
```
## SDK integration
Go accesses browser globals through `syscall/js`. Ebiten's game loop is synchronous from Go's perspective — call the SDK just before `RunGame`:
**Calling `Wavedash.init()` is required.** Your game stays hidden behind the Wavedash loading screen until you do. Call it once your game is ready to play.
```go
package main
import (
"syscall/js"
"github.com/hajimehoshi/ebiten/v2"
)
type Game struct{}
func (g *Game) Update() error { return nil }
func (g *Game) Draw(screen *ebiten.Image) {}
func (g *Game) Layout(_, _ int) (int, int) { return 900, 600 }
func main() {
sdk := js.Global().Get("Wavedash")
sdk.Call("updateLoadProgressZeroToOne", 1)
sdk.Call("init")
if err := ebiten.RunGame(&Game{}); err != nil {
panic(err)
}
}
```
Call `updateLoadProgressZeroToOne(...)` with intermediate values during async asset loading (embedded files, HTTP fetches, etc.). `init()` automatically signals load completion, so call it last.
## HTML shell
A minimal shell that loads `wasm_exec.js`, instantiates the module, and hands off to Ebiten:
```html
```
## Build script
```bash
#!/usr/bin/env sh
set -eu
mkdir -p build
GOOS=js GOARCH=wasm go build -ldflags="-s -w" -o build/game.wasm .
if [ -f "$(go env GOROOT)/lib/wasm/wasm_exec.js" ]; then cp "$(go env GOROOT)/lib/wasm/wasm_exec.js" build/wasm_exec.js
elif [ -f "$(go env GOROOT)/misc/wasm/wasm_exec.js" ]; then cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" build/wasm_exec.js
fi
cp web/index.html build/index.html
```
## wavedash.toml
```toml
game_id = "YOUR_GAME_ID_HERE"
upload_dir = "./build"
```
## Other SDK features
Once initialized, `Wavedash` exposes leaderboards, achievements, stats, and user data. Call them the same way:
```go
sdk.Call("setAchievement", "first_win", true)
user := sdk.Call("getUser")
```
See the [SDK reference](/sdk/overview) for the full API.