A tight, responsive 2D platformer written in Jai, targeting Android ARM64.

• Super Meat Boy-style controls

  • Instant acceleration (no floaty movement)
  • High air control
  • Wall sliding and wall jumping
  • Variable jump height (release to cut jump short)
  • Coyote time (jump grace period after leaving platform)
  • Jump buffering (queue jump before landing)

• Android ARM64 native

  • Pure NativeActivity (no Java)
  • OpenGL ES 3.0 rendering
  • Touch controls with virtual D-pad
  • Internet and file system permissions

• JSON level loading

  • Tile-based collision
  • Hazards (instant death)
  • Spawn points and goals
  • Easily create new levels

jai-meatboy-android/
├── src/
│   ├── main.jai           # Entry point, Android setup
│   ├── game.jai           # Game state, core logic
│   ├── player.jai         # Player controller (SMB-style)
│   ├── level.jai          # Level loading from JSON
│   ├── renderer.jai       # OpenGL ES 3.0 batch renderer
│   ├── physics.jai        # Collision utilities
│   └── input_handler.jai  # Touch & keyboard input
├── assets/
│   └── levels/
│       └── level1.json    # First level
├── android/
│   └── AndroidManifest.xml
├── build.jai              # Build configuration
├── package_apk.sh         # APK packaging script
└── README.md

• Jai compiler (beta access required)
• OpenGL 3.3+ capable GPU

• Jai compiler with cross-compilation support
• Android NDK r21+ (for ARM64)
• Android SDK with build-tools 34+
• Java JDK (for APK signing)

# Debug build
jai build.jai

# Release build
jai build.jai - release

# Run
./build/desktop/meatboy

# Build native library
jai build.jai - android

# Package APK
chmod +x package_apk.sh
./package_apk.sh

# Install on device
adb install -r build/output/JaiMeatboy.apk

Levels are JSON files in assets/levels/:

{
    "name": "Level Name",
    "par_time": 15.0,
    "width": 40,
    "height": 23,
    
    "spawn": { "x": 3, "y": 19 },
    "goal": { "x": 36, "y": 3, "width": 2, "height": 3 },
    
    "background_color": [25, 25, 40],
    
    "tiles": [
        [1, 1, 1, ...],  // 1 = solid, 0 = empty
        ...
    ],
    
    "hazards": [
        { "x": 6, "y": 20, "width": 3, "height": 1 },
        ...
    ]
}

• 0 - Empty (air)
• 1 - Solid (collision)
• 2 - One-way platform (planned)

• Arrow Keys / WASD - Move
• Space / Z / Up - Jump
• Escape - Pause
• Ctrl+Q - Quit

• Left side - Virtual D-pad (drag to move)
• Right side - Jump button
• Back button - Pause

The app requests:

• INTERNET - For future online features
• READ/WRITE_EXTERNAL_STORAGE - Save files, custom levels
• WAKE_LOCK - Keep screen on during play

• Zero-cost abstractions
• Compile-time execution
• No garbage collector
• Direct memory control
• Fast iteration times

• Batch renderer for efficiency
• Single draw call per frame (typically)
• Colored quads (no textures yet)
• Camera with smooth follow and screen shake

• Fixed timestep (60 FPS)
• Tile-based collision
• AABB overlap detection
• Sweep collision for tunneling prevention

• Sprite-based rendering
• Particle effects polish
• Sound effects
• Music
• More levels
• Level editor
• Leaderboards
• Replays

MIT License - See LICENSE file

Inspired by:

• Super Meat Boy (Team Meat)
• Celeste (Matt Makes Games)
• N++ (Metanet Software)