HelioSim – Real-time N-body simulator in WebAssembly

Name: HelioSim – Real-time N-body simulator in WebAssembly
Availability: InStock
Author: JustClemens

by JustClemens·Feb 26, 2026·1 point·0 comments

Visit Project View on HN

AI Analysis

●●SolidWizardryEye CandyRabbit Hole

C++ + OpenGL ES compiled to WASM—browser physics sim with predictive orbits.

Strengths

•Full simulation and rendering pipeline in WebAssembly shows genuine WASM+graphics mastery
•Predictive orbit trails and collision detection add physical accuracy beyond basic n-body
•Live browser demo is immediately interactive and performs well

Weaknesses

•Physics simulator is a solved category; many alternatives exist (three.js sims, desktop tools)
•First WASM project by author—lacks polish in JS↔C++ bridging, limiting extensibility

Post Description

Hi HN!

I built HelioSim, a real-time N-body gravitational system simulator running directly in the browser via WebAssembly.

It’s written in C++ and uses OpenGL ES 3.0, GLFW, and Emscripten. The entire simulation and rendering pipeline runs in WebAssembly.

Features: - Real-time N-body gravitational simulation - Predictive orbit trails - Collision handling - Time controls (slow motion / fast-forward) - Dynamic body spawning

This was my first larger WebAssembly project, and I was honestly surprised how well modern browsers handle a C++ + OpenGL ES pipeline compiled to WASM.

One interesting challenge was bridging events and state between JavaScript and C++, which can honestly be a bit exhausting.

Source code:https://github.com/clemenskoprolin/heliosim

I’d love feedback on performance on other machines. Thanks!