What is this?

This is a hobby, tiny 3D engine targetting WASM and the browser, capable of doing N-body physics simulations.

The main goal is to be able to quickly visualize and move around solar systems in the correct scale, and simulate their motion and lighting in a natural way. Also this was a way for me to practice Rust, Entity-Component systems and targetting the WebAssembly ecosystem.

I tried to stick to trusted source data and approximations for body physical parameters, so most of this data comes from NASA's HORIZONS system and JPL's Small-Body Database Search Engine, and when required evolved to the J2000 epoch using the mean orbital elements. It uses a bunch of Python scripts (see /scripts) to download/process all of this data and combine it into a set of large .json files (/public/database), which are read by the app. The source data downloaded from NASA is not on this repo, but the final database files are.

I have many cool plans for this like visualizing asteroids/comets in the solar system, artificial satellites around the Earth and doing physically-correct relativistic motion effects. Progress doesn't go as fast as I would like though, as this is just one of many side projects.

Sources and references

• CC4 solar system body textures from here: https://www.solarsystemscope.com/textures/
• Starmap from the Hipparcos-2, Tycho-2 and Gaia Data Release 2: https://svs.gsfc.nasa.gov/4851
• https://360toolkit.co/ to convert the cubemap images
• egui_web as a source of the gui_backend inner crate

Usage:

Running

Check it out on your browser by clicking here!

It's still a work-in-progress though, and it may stutter a little bit while it downloads all the high-resolution textures.

Development

Run this:

git clone https://github.com/1danielcoelho/system-viewer
cd system-viewer
npm install
npm run dev

It should open the browser right away. If not you can open http://localhost:9000/ manually.

Within the app, make sure you go to Settings and Allow Local Storage if you wish: That will allow it to store app state on your browser, as well as the last opened scene.

See the /schemas folder for schemas describing the format for the database and scene description files. New scenes can be added to the /public/scenes folder and hot-reloaded, but will need to also be listed on the /public/scenes/auto_load_manifest.txt file.

Deployment

Run this:

git clone https://github.com/1danielcoelho/system-viewer
cd system-viewer
npm install
npm run build

The packaged build is fully contained within /dist. To deploy the build locally for a sanity check, run this from /dist:

python -m http.server 8000

Then open http://localhost:8000/

Source data

This part is not meant to be done by users/dev, but if you have the source data on your drive, run /scripts/main.py. There are a few hard-coded paths within the files pointing to where that data is, and those would need to be manually edited. Some of the source data can be downloaded with the download_horizons_files.py script.

Features:

• WebGL2 (GLSL 300);
• Egui for immediate-mode UI;
• wasm-pack and wasm-bindgen for Rust to WASM;
• Full, custom entity-component-system for Data Oriented Design;
• Semi-implicit Euler integration for N-body (may be switched to RK4 eventually).

Conventions

• UV(0, 0) is on top left
• Right-handed, Z-up
• NDC space: Left-handed, X right, Y up, Z into the screen, (-1, -1, -1) on bottom left close, (1, 1, 1) on top right far