# ebruneton/precomputed_atmospheric_scattering

This project provides a new implementation of our EGSR 2008 paper "Precomputed Atmospheric Scattering".

Repository: https://github.com/ebruneton/precomputed_atmospheric_scattering
Canonical: https://ross.abutalabs.com/products/precomputed_atmospheric_scattering
Homepage: https://ebruneton.github.io/precomputed_atmospheric_scattering/
Language: C++
License: BSD-3-Clause
License Family: permissive
Topics: atmosphere, opengl, shader, sky, webgl
Last push: 2025-10-05T18:39:46+00:00

## Health v2 (maintenance only)
Score: 52/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 45, release rhythm 35, longevity 100
- inputs: {"age_days": 3502, "days_push": 332, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1061, forks 136 (observed 2026-08-28T04:03:26.037346+00:00)

## What it is
A reference C++/OpenGL implementation of the Precomputed Atmospheric Scattering (EGSR 2008) paper, with extensive documentation, unit tests, and a WebGL demo. It precomputes atmospheric scattering tables for realistic sky, aerial perspective, and light shaft rendering on Earth or other planets.

## Use cases
- render a physically based sky in a game engine
- simulate atmospheric scattering for other planets
- add aerial perspective and light shafts to a renderer
- learn how precomputed atmospheric scattering works
- port atmospheric scattering shaders to WebGL
- compute sky luminance from a solar spectrum

## When to choose
- you need physically accurate sky and atmosphere rendering
- you want a well-documented, tested reference implementation of the EGSR 2008 paper
- you need to adapt scattering to non-Earth planets
- you want a WebGL-ready atmosphere demo

## When to avoid
- you need a full game engine or turnkey rendering framework
- you want simple stylized sky gradients without physical accuracy
- you need the complete light shaft shadow volume algorithm, which is only partially implemented

## Facets
- artifact type: library
- maturity: stable
- function: graphics, simulation
- domain: graphics, simulation
- platform: cpp, cross-platform
- tags: atmospheric-scattering, opengl, webgl, sky-rendering, precomputed, physically-based-rendering, shader, game-development, web

## Member repositories
- ebruneton/precomputed_atmospheric_scattering (main) score 52

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:26.037346+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:56:49.941852+00:00, confidence not recorded.
  - readme: https://github.com/ebruneton/precomputed_atmospheric_scattering (fetched 2026-08-28T04:03:26.037346+00:00, sha 4ec81cfb64c7)
  - homepage: https://ebruneton.github.io/precomputed_atmospheric_scattering/ (fetched 2026-08-29T12:58:29.545468+00:00, sha 27ff669668d7)
- Data as of 2026-08-30T08:39:29.467469+00:00.