Real-time PathTracing with global illumination in WebGL

Jaw-dropping browser lighting you can play with—and yes, it runs on a potato-phone

TLDR: A free in-browser demo brings movie-like lighting in real time. Comments swing from awe (it runs on “potato phones”) to complaints about camera controls, plus a mini-drama over whether it’s AI-written—spoiler: it’s hand-made, and the visuals slap.

The web just got a glow-up: a hand-made renderer delivers cinematic lighting—light bouncing, soft shadows, reflections—right in your browser. The demos range from a Geometry Showcase, to a moody Ocean & Sky, even the classic Cornell Box everyone uses to test realistic lighting. Commenters are doing spit-takes: ttul’s nostalgic “POV-Ray, but in my browser—WTF!” energy meets pixelpoet’s is this AI? side-eye, who then concedes it’s human-crafted and gushes over glass-sphere caustics from a famous lighting paper.

Then the controls sparked drama: modeless wants dragging to orbit the camera instead of panning, saying panning hides the 3D wow-factor, while gamers defend the first‑person WASD setup. Meanwhile, flowerbreeze flexes that it “runs on my potato‑phone,” turning performance into a meme. Crowds keep clicking: God Rays, Water, and Terrain. Also, the Volumetric Rendering demo shows glass spheres casting spooky light patterns almost instantly. Non‑nerd translation: path tracing simulates lots of light rays until images look real; global illumination is the extra bounce that makes rooms stop looking fake. Verdict: it’s fast, shiny, and surprisingly mobile‑friendly—just fix those camera vibes.

Key Points

  • THREE.js-PathTracing-Renderer provides real-time path tracing with global illumination and progressive rendering in the browser.
  • The project includes multiple live demos (e.g., Geometry Showcase, Cornell Box, Water, Volumetrics, Light Shafts) targeting 30–60 FPS, including on mobile.
  • Several scenes combine ray tracing with ray marching to achieve oceans, skies, water surfaces, and volumetric effects.
  • Interactive controls support desktop and mobile, including camera movement, orthographic/perspective toggle, and depth-of-field adjustments.
  • Terrain and Arctic Circle demos use ray marching for large procedural environments, minimizing mesh complexity (e.g., screen-space quad).

Hottest takes

"I suspected it might be an AI thing" — pixelpoet
"in realtime and in my browser. WTF!" — ttul
"most of the demoes run on my potato-phone" — flowerbreeze
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