ebiten

Ebitengine (Ebiten v2)

Go 2D game engine skill - covers the full Ebitengine API and ecosystem. Routes to sub-skills by domain.

Ebitengine is a dead simple 2D game library for Go. Cross-platform: desktop (Windows/macOS/Linux), mobile (iOS/Android), WebAssembly, and Nintendo Switch.

Import: github.com/hajimehoshi/ebiten/v2

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When to Use This Skill

You are building a 2D game or interactive graphical application in Go using Ebitengine (Ebiten v2).

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Sub-Skill Routing

If you need...	Use Sub-Skill
Game loop, ebiten.Game interface, TPS/FPS, window config	ebiten/game-loop
Keyboard, mouse, gamepad, touch input	ebiten/input
Images, sprites, tiles, camera, shaders, text	ebiten/rendering
Entity Component System (Donburi, Ark, etc.)	ebiten/ecs
Collision detection, physics, pathfinding	ebiten/physics
Sound effects, music, audio playback	ebiten/audio
WASM, mobile, Steam, cross-platform build	ebiten/deployment
Asset loading, tilemaps (LDtk, Tiled), resource management	ebiten/resources

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Minimal Game Template

package main

import (
	"log"

	"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(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
	return 320, 240
}

func main() {
	ebiten.SetWindowSize(640, 480)
	ebiten.SetWindowTitle("Title")
	if err := ebiten.RunGame(&Game{}); err != nil {
		log.Fatal(err)
	}
}

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Ecosystem Libraries

Architecture

Library	Purpose	Stars
donburi	ECS for Ebitengine	500+
ark	Archetype-based ECS	400+
mizu	ECS framework	400+
ebiten-extended	Godot-inspired scene graph, camera, sprites	100+

GUI

Library	Purpose
ebitenui	Full widget library (buttons, lists, combo boxes)
furex	Flexbox-based UI framework
etk	Toolkit for graphical interfaces

Graphics & Animation

Library	Purpose
ganim8	Animation library inspired by anim8
aseprite	Aseprite file parser (layers, tags, slices)
aseplayer	Aseprite animation player
etxt	Font management and text rendering
colorgrad	Color scales for data viz and games
tetra3d	3D software renderer via Ebitengine

Physics & Collision

Library	Purpose
resolv	2D collision detection and resolution
cp	Chipmunk2D physics port
box2d-go	Box2D v3 physics port
coll	2D collision detection

World & Maps

Library	Purpose
ldtkgo	LDtk level designer loader
go-tiled	Tiled map editor (TMX) parser
dngn	Random map generation
paths	A* pathfinding

Input

Library	Purpose
ebitengine-input	Godot-inspired action input system

Audio

Library	Purpose
resound	Sound effects (delay, low-pass, panning, distortion)
xm	XM music format playback

Resources & Tools

Library	Purpose
ebitengine-resource	Resource manager
gdata	Cross-platform gamedata storage
kamera	Camera with shake, lerp, zoom

Networking

Library	Purpose
necs	Networking layer for Donburi ECS

Integration

Library	Purpose
go-steamworks	Steamworks SDK binding

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Key Concepts

TPS vs FPS

• TPS (Ticks Per Second): How often Update() is called. Default: 60. Set via ebiten.SetTPS().
• FPS (Frames Per Second): How often Draw() is called. Tied to monitor refresh rate.
• ebiten.CurrentTPS() / ebiten.CurrentFPS() for monitoring.
• Use ebiten.SetTPS(ebiten.SyncWithFPS) to decouple update from render.

Coordinate System

• Origin (0,0) is top-left
• X increases right, Y increases down
• Layout() defines logical screen size; engine scales to window

Image Model

• ebiten.Image is the core drawing surface
• screen parameter in Draw() is the final render target
• Use SubImage() for sprite sheet regions (zero-copy)
• Use ebiten.NewImage() for off-screen buffers

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Anti-Patterns

Don't	Do
Call ebiten.NewImage() in Update()/Draw()	Create images once in NewGame() or load phase
Use floating-point for pixel positions	Use float64 with GeoM (engine handles sub-pixel)
Load assets in Draw()	Load in init() or dedicated load phase
Ignore Layout() return values	Return consistent logical size
Use ebiten.IsKeyPressed() for single actions	Use inpututil.IsKeyJustPressed() for one-shot triggers
Create *ebiten.DrawImageOptions each frame	Reuse and reset with opts.GeoM.Reset()
Mix game state with rendering logic	Keep Update() pure logic, Draw() pure rendering

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References

• Docs: https://ebitengine.org/en/documents/
• Cheat Sheet: https://ebitengine.org/en/documents/cheatsheet.html
• Examples: https://github.com/hajimehoshi/ebiten/tree/main/examples
• Awesome List: https://github.com/sedyh/awesome-ebitengine
• Kage Shaders: https://ebitengine.org/en/documents/shader.html
• TPS vs FPS: https://github.com/tinne26/tps-vs-fps

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Remember: Ebitengine is intentionally simple. Start with the Game interface, add libraries only when needed.

Limitations

• Use this skill only when the task clearly matches the scope described above.
• Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
• Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.