GoP

GoP is a 2D platformer built in Go with Ebiten v2. The repository includes both:

• a playable game runtime
• a full level editor with in-editor playtesting

Levels are stored in Tiled-compatible JSON and loaded from embedded assets.

Requirements

• Go 1.24+
• A desktop environment that supports Ebiten

Quick Start

Run the game

go run ./cmd/game

Run the level editor

go run ./cmd/editor

Build

# Game
make build
# or
go build -o bin/game ./cmd/game

# Editor
make build-editor
# or
go build -o bin/editor ./cmd/editor

Common Development Commands

# Tests
go test ./...
# or
make test

# Format
gofmt -w .
# or
make fmt

# Dependency cleanup
go mod tidy
# or
make tidy

# Static checks
go vet ./...

Utility Tools

# Generate test sprite sheet
go run ./cmd/gensheet

# Generate tileset
go run ./cmd/gentiles

# Verify level object parsing
go run ./cmd/verify_objects

Project Structure

cmd/               # Entrypoints (game, editor, tooling)
internal/
  app/             # App loop and scene lifecycle
  scenes/sandbox/  # Main game scene
  entities/        # Gameplay entities (platforms, switches, doors, etc.)
  physics/         # Collision and movement logic
  world/           # Tilemap loading/rendering and object parsing
  camera/          # Camera behavior (deadzone/smoothing)
  gfx/             # Sprite and animation helpers
  gameplay/        # Spawn/state orchestration
  input/           # Input abstractions
  assets/          # Embedded asset access
  editor/          # Level editor implementation
  game/            # Game tuning parameters
  time/            # Fixed timestep utilities
assets/            # Source art and level JSON
docs/              # Design and architecture docs

Editor

The editor supports painting/erasing/fill/select/object placement, undo/redo, validation, and playtest mode.

• Press P in the editor to enter playtest.
• Press Escape to return from playtest to editing.
• Press R during playtest to restart.

Screenshots

Tile Mode

Collision Mode

Playtest Mode

Architecture Highlights

• Scene-based runtime: scenes implement update/fixed-update/draw/layout lifecycle.
• Fixed timestep physics: simulation runs at a stable update rate independent of rendering.
• ID-based entity linking: interactions (for example switch-to-door) are resolved by IDs via a registry.
• RenderContext drawing model: rendering passes shared camera/debug/screen context instead of raw offsets.

Assets and Levels

Assets are embedded in the binary via Go embed and loaded through internal/assets.

• assets/tiles/tiles.png
• assets/sprites/test_sheet.png
• assets/levels/level_01.json

Documentation

See docs/ for detailed subsystem designs:

• docs/architecture-overview.md
• docs/level-editor-design.md
• docs/tilemap-collision-design.md
• docs/moving-platforms-design.md
• docs/asset-rendering-design.md
• docs/feel-camera-design.md
• docs/interactive-world-design.md

CI

CI runs:

• go vet ./...
• go test ./...