Plan M — GPU Barnes-Hut Octree (The Best)

This repository hosts Plan M: a GPU-resident Barnes-Hut octree implementation for interactive N-body simulation and visualization.

Overview

• Plan M implements a 3D octree (64^3 L0 grid) stored in 2D textures using Z-slice stacking.
• Forces are computed in GLSL using a 3D Barnes-Hut traversal with Plummer softening.
• The app is designed as a browser-based demo built with Three.js and raw WebGL2 shaders.

Quick start (development)

npm install
npm run build
npm start

Open http://localhost:8333 in your browser. The landing page runs Plan M by default.

Controls

• • / = : increase Plan M timestep (faster)
• • / _ : decrease Plan M timestep (slower)
• 0 : reset Plan M timestep

Project Layout (important)

• src/plan-m/ — Plan M implementation (shaders, pipeline, integrator)
• src/index.js — application entry point (now runs Plan M only)
• public/ — static landing page and built JS

Legacy plans

• Older experimental plans (Plan A, C, D) have been archived under legacy/ and are no longer part of the primary UI. They remain available for reference and historical comparison.

Future

• The codebase can be converted to an npm package or library in the future; current focus is to keep a production-ready demo app.

License: MIT