Powder4J

Powder4J is a high-performance 2D cellular automata physics engine designed for simulating granular materials, liquids, gases, and their physical interactions on a discrete grid.

Overview

Powder4J models complex emergent physics through local cell interactions. By applying custom rules for individual elements (such as gravity, displacement, ignition, and fluid dynamics), simple particle-level behaviors combine to create rich, interactive environments in real time.

Core Features

• Dynamic Material Engine: Simulates distinct physical properties for solids, fluids, gases, and reactive elements (Sand, Water, Fire, Lava, Mercury, etc.) with custom visual shading and noise filters.
• Radial Selection Menus:
  • Element Wheel (TAB): Quick-access radial HUD to select materials on the fly.
  • Change Brush Size (Wheel): Adjusts the brush size in real-time.
  • Shape Wheel (ALT): Radial menu to switch brush geometries (Circle, Square, Triangle).
  • Tool Wheel (SHIFT): Radial menu to switch brush tools (Brush, Eraser, Fill).
  • Temperature Regulator (CTRL + Wheel): Adjusts the ambient temperature of the scene.
  • Toggle Current Element Info (V): Displays the current material's properties in a HUD.
  • Toggle HeatMap (T): Displays a heat map of the current material's density.
  • Clear Everything (E): Just a tiny bit more convinient than clearing by hand.
  • Take Screnshot (F12): Saves a screenshot of the current view.
• Customizable Brush System: Real-time radius adjustments with visual fading HUD slider feedback and geometric shape masking.
• Fast Buffer Rendering: Optimized direct pixel buffer strategy ensuring high frame rates even under heavy grid loads.

Getting Started

Prerequisites

• Java 25 or higher
• Maven

Build and Run

To build and execute Powder4J from the project root:

mvn clean compile exec:java -Dexec.mainClass="org.p4j.App"