Space Bike

Space Bike is a side-scrolling physics-based Android game where you pilot a space bike through obstacle-filled levels. Tilt your device or use on-screen controls to lean the bike, and tap the screen to drive forward or reverse. Beat each level before your battery runs out!

Gameplay

• Objective: Reach the end of each level without crashing before the timer expires.
• Controls:
  • Tilt controls — tilt your device left/right to lean the bike.
  • Button controls — tap the right side of the screen to drive forward, the left side to reverse, and the center to brake.
  • Slider bar — an alternative touch layout where a horizontal strip controls both steering and throttle.
• Gravity panel — in later levels you can rotate gravity in any direction (up, down, left, right) or disable it entirely. Tap the directional arrows in the top-left corner of the screen.
• Battery meter — a countdown bar at the top of the screen represents your remaining power. When it reaches zero the bike shuts down.
• Level progression — complete a level to unlock the next one. Progress is saved automatically.

Levels

#	Name	Time Limit
1	Tutorial	4 min 10 s
2	Level 1	1 min
3	Level 2	2 min 30 s
4	Level 3	2 min 30 s

Settings

Option	Values
Graphics detail	Low / Medium / High
Tilt sensitivity	Slow / Normal / Fast
Feedback	Vibrate / Sound
Control layout	Normal buttons / Slider bar

Project Structure

src/main/
├── AndroidManifest.xml
├── assets/
│   ├── fonts/               # Custom fonts (space.ttf, sketch.ttf, Brushed.ttf)
│   └── doc/                 # Emini Physics Engine API documentation
├── java/com/doodle/physics2d/
│   ├── full/spacebike/      # Game logic
│   │   ├── DoodleBikeMain   # Main game Activity (physics loop, input, UI)
│   │   ├── Level            # Level-select and settings Activity
│   │   ├── LevelControl     # Level configuration (world files, gravity, timers)
│   │   ├── GameEvents       # Physics event handler (collisions, win/death)
│   │   ├── SoundManager     # Sound pool wrapper
│   │   └── MyCount          # (stub / unused)
│   └── graphics/            # Rendering layer
│       ├── GraphicsWorld    # Physics world + canvas drawing + sensor input
│       ├── SimulationView   # SurfaceView that hosts the game canvas
│       └── UserImages       # Bitmap loader for bike body and wheels
└── res/
    ├── layout/              # XML layouts (rotategame, level2, level3, …)
    ├── drawable/            # UI assets and shape drawables
    ├── raw/                 # Physics world files (.phy) and audio
    └── values/              # strings.xml, general.xml

Technology

• Language: Java
• Platform: Android (minSdk 7, targetSdk 20)
• Physics: Emini Physics Engine v1.3.4 by Alexander Adensamer — a 2D fixed-point rigid-body physics library
• Sensor: SensorManager.SENSOR_ACCELEROMETER for tilt controls
• Audio: SoundPool for sound effects; MediaPlayer for music (imported but managed via SoundManager)

Building an APK

Prerequisites

• Java Development Kit (JDK) 11 or 17 — required by the Android Gradle plugin.
• Android SDK — install via Android Studio or the standalone command-line tools. Make sure ANDROID_HOME (or ANDROID_SDK_ROOT) is set.
• Android SDK Platform 34 — install through Android Studio's SDK Manager or with:

  sdkmanager "platforms;android-34" "build-tools;34.0.0"

Build with the Gradle wrapper

If you have the Gradle wrapper installed (or generate it with gradle wrapper), you can build from the command line:

# Debug APK
./gradlew assembleDebug

# The APK will be at:
# build/outputs/apk/debug/SpaceBike-debug.apk

To create a release APK you must sign it. First create a keystore, then build:

# Generate a keystore (one-time step)
keytool -genkey -v -keystore my-release-key.jks \
  -keyalg RSA -keysize 2048 -validity 10000 -alias spacebike

# Build the release APK
./gradlew assembleRelease

# Sign the APK
apksigner sign --ks my-release-key.jks \
  build/outputs/apk/release/SpaceBike-release-unsigned.apk

Build with Android Studio

1. Open the project root folder in Android Studio.
2. Wait for Gradle sync to complete.
3. Select Build → Build Bundle(s) / APK(s) → Build APK(s).
4. The generated APK will be in build/outputs/apk/.

Install and run

# Install the debug APK on a connected device or emulator
adb install build/outputs/apk/debug/SpaceBike-debug.apk

Credits

• Game development: Brian Purgert
• Physics engine: Alexander Adensamer — Emini Physics

License

Copyright © 2010 Brian Purgert. All rights reserved.
Physics engine copyright © 2010 Alexander Adensamer (Emini Physics). All rights reserved.