Planet Formation Playground

A playful Swing demo of a protoplanetary disk: dust orbits a warm sun, bumps together, and grows into baby planets. Built to show a 4-year-old how planets form, with simple tools, comets, captions, and synthesized sounds.

What’s Inside

• Simulation: physics, collisions, auto-comets, naming/stages, events.
• RenderPanel: draws bodies, HUD, labels; view-only zoom via mouse wheel.
• ControlBar: toolbar for tools/comets/shake/cleanup/auto-comet toggle.
• InputBinder: keyboard/mouse bindings for tools and toggles.
• Managers: CaptionManager (kid-friendly captions), SoundManager + Sound (whoosh/chime synth).
• Data/Styling: Body, Stage, ToolMode, SimulationSnapshot, PlanetStyling (colors/names), ToolModeHolder, FormatUtil.

Run It

• Eclipse: run com.example.PlanetFormationDemo.PlanetFormationDemo.
• CLI (with Maven on PATH and GUI available):
  mvn -q compile exec:java -Dexec.mainClass=com.example.PlanetFormationDemo.PlanetFormationDemo

Note: Swing needs a display; headless shells will throw HeadlessException.

Controls

• Tools: 1 Star wand, 2 Wind, 3 Gravity glove.
• Toolbar buttons: Make comet, Shake disk, Clean up dust, Toggle auto-comets.
• Mouse: Click/drag applies current tool; mouse wheel zooms view (non-destructive).
• ESC closes the app.

Behavior Highlights

• Planets keep their names on merges; labels show name + particle count after 5k particles.
• Color stages: rock → ocean → garden → mystery at lower thresholds for variety.
• Auto-comets (12–24s interval) on by default; toggle via toolbar or C.
• Captions react to events (new planet, stage change, dense dust, comets) with friendly text.
• Sounds: synthesized whoosh on comets, chime on meaningful merges (gated to avoid flood).
• Sun/disk recenters on resize; bodies fill the window at startup.

Build Notes

• Maven compiler set to Java 25; adjust pom.xml if needed for your JDK.
• If Maven fails on *.part.lock in ~/.m2, delete stale lockfiles and retry.
• Build output should go to target/; source tree should not contain .class files (.gitignore provided).

Files of Interest

• src/main/java/com/example/PlanetFormationDemo/PlanetFormationDemo.java — Bootstrap UI.
• Simulation.java, RenderPanel.java, ControlBar.java, InputBinder.java — core components.
• CaptionManager.java, SoundManager.java, Sound.java — captions/sounds.
• PlanetStyling.java, FormatUtil.java, Body.java, Stage.java, ToolMode.java, ToolModeHolder.java, SimulationSnapshot.java — data/styling/utilities.

Enjoy exploring how “space dust” turns into “planet babies!” 🎈