go-infinite-rail-generator

README

Go Infinite Rail Generator

The Go Infinite Rail Generator procedurally generates a one-dimensional rail word.

The generator uses Perlin Noise to achieve a smooth distribution of tracks. It generates the world tile-wise. The above image consists of six tiles next to each other. A tile represents 100m of track. This results in a possible world size of 19 times the earth's equatorial perimeter.

Currently, the generator is work in progress and will be improved by adding more structures and details to the generation algorithm.

Content

1. Features
2. Build Instructions
3. Render a single Tile
4. Run a Tile Server

Features

Generated structures

• variable amount of tracks
• areas with many tracks (e.g stations) and over-land tracks with only one or two tracks.
• switches when tracks merge or diverge
• siding tracks

Architecture

• Command-Line Tool to render a certain tile as SVG
• An OSM tile server to display the world like OSM maps
• A simple web app to display the generated world dynamically

Build instructions

You can either download the binaries from the Release tab (currently Linux only), or build the application from scratch.

Requirements

• Go 1.16 or higher
• npm 6.14.13 (only needed if you want to build the minimalistic Angular Frontend)

Only Go Application

If you just want to render SVG tiles locally, or running the tile server, it suffices to execute

go build cmd/rail-generator.go

Go Application and Web Frontend

If you want the minimalistic web frontend, too, just execute the command

/bin/bash build.sh

It compiles both the Go application and the frontend and puts everything in a directory dist. If you cannot execute bash, the manual steps are:

1. Build the Angular app: npm run-script build
2. Rename the dist directory into html.
3. Put the generated Go file into the same directory as the html directory.

Render a single tile

The following command renders a single tile to the standard output:

rail-generator [--seed=SEED] svg [--tile=TILE] [--size=SIZE]

If a seed is given, then subsequent executions of the command will produce the same rail world. The tile flag signifies which tile of the world is rendered, it defaults to "0". The size is the size of the SVG in pixel and is 200 pixel as default.

Run a tile-server

To run a tile server, execute the following command:

rail-generator [--seed=SEED] serve [--bind=BIND] [--port=PORT] [--shift=SHIFT]

The seed has the same function as in the rendering usecase. The flags bind and port define how the tile server is reachable. If they are omitted, the server binds to 127.0.0.1:9551.

The shift flag is a number which is added onto the x coordinate on each request to the tile server. The default is -131068. If you use a library like Leaflet or Openlayers to display the tiles, the library will request the tile * x=121068, y=131072* at coordinates longitude=1, latitude=0.00138 with zoom=18. Thus, via shifting, the map shows the first world tile at these coordinates near the origin.

The command runs a server with three endpoints:

• GET /tiles?tile={x}&vertical={y}&seed=${seed} Returns the x-shift world tile. Since the generated world is one-dimensional, the endpoint returns an empty SVG for values of y other than 131072. Since this value is near the equator, the maximal size of the world is used. The seed request parameter allows to overwrite the default seed (see progam flags) temporarily for the request.
• GET /config Returns a JSON file of the format {"defaultSeed":"defaultSeed"}.
• GET / (and any other endpoint) Can be used in browsers to download a minimalistic web app. This app utilizes Leaflet to explore the world.

The tile server is configured to allow CORS requests.

License

MIT. See License.