ishtaria-worldgen

Primary source: https://git.vitexsoftware.com/Ishtaria/ishtaria-worldgen (development happens there). GitHub (https://github.com/Vitexus/ishtaria-worldgen) is a secondary mirror; packages and binaries are not built from GitHub.

Deterministic procedural generator of an Earth-sized planet. Terrain is a pure function of (seed, position) on a cube-sphere; worlds store only deltas.

ishtaria-worldgen 42 256 > planet.pgm     # six cube faces as a height-map strip

While rendering, the binary writes PROGRESS <done>/<total> lines to stderr (one per completed face row). stdout stays a clean P5 PGM so scripts that only capture stdout keep working; ishtaria-admin reads both to drive its progress bar when generating or preparing a world update.

The generator combines continental shelves, lowland hills and ridged mountain regions. Noise is sampled in three-dimensional sphere coordinates, so neighboring cube faces meet without seams. Default elevation amplitude is 8000 metres. The strip is a 16-bit P5 PGM (maxval 65535, big-endian): a sample is the height in steps of 0.25 m from -8000 m, sea level is exactly 32000, water samples never rise above it and land samples never sink to it. The local relief of the seed (up to about +/-12 m, faded out at the coast) is generated into every land sample (strip and relief modules, ADR 0020), so the server and every client read one surface. Servers derive lakes, downhill drainage, river catchments and climate biomes from the persisted map; clients render water, snow and biome-selected scenery.

Real planets (datadisks)

A story datadisk may define the world's real planet: the real continent outlines, heights and water of the Earth as it was when the story takes place (maximum historical fidelity — see ADR 0017 and the datadisk schema's world.terrain). The disk ships two equirectangular P5 PGMs of the same size (width == 2 * height, row 0 at +90 degrees, column 0 at -180 degrees): a 16-bit heightmap (maxval 65535, big-endian, pixel = elevation in metres as a signed value, 0 is sea level) and an 8-bit water mask (0 land, 255 water). --earth renders the strip from them instead of the noise:

ishtaria-server --print-world-terrain gilgamesh    # prints the disk's two rasters
ishtaria-worldgen --seed 2577465639 --earth HEIGHT.pgm --water MASK.pgm 512 > planet.pgm

The sphere is mapped to the planet's real geography as latitude = asin(y) and longitude = atan2(-z, x) (the +Y face is the north pole; east is towards -Z, so the map is not a mirror image), so the server's compass and historical bearings are the real ones. The water mask decides the coastline: water pixels stay at or below sea level (so the shallow Persian Gulf stays sea), land pixels stay above it (so the dry Qattara depression stays land). The seed (--seed, required in this mode; the world's seed as the server stores it) only sets the local relief generated into the land samples.

This terrain algorithm changes newly generated maps, including maps generated with an existing seed. Do not regenerate over an imported world's source file or overwrite its database. Existing imports remain intact and conflicting imports are rejected. An algorithm upgrade for a populated world requires a separate version/migration decision. The finite PGM is a preview, not metre-resolution Earth terrain or hydraulic/erosion simulation.

Installation

Debian / Ubuntu (x86-64) only:

echo "deb http://repo.vitexsoftware.com $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/vitexsoftware.list
sudo wget -O /etc/apt/trusted.gpg.d/vitexsoftware.gpg http://repo.vitexsoftware.com/keyring.gpg
sudo apt update
sudo apt install ishtaria-worldgen

License: MIT

Part of Ishtaria

Ishtaria is an open-source, persistent, federated virtual planet of Earth size. Documentation: https://vitexsoftware.github.io/ishtaria-docs/ · All repositories: https://git.vitexsoftware.com/Ishtaria