Work in progress train graph + game demo on top.

Play

Fetch, run npm install, and run with dhost or something that will rewrite your ESM imports:

dhost -m

Focus and tap "a" to add a line. Use your mouse and click to finish the line (potentially joining to other lines).

Tap "s" to add a train (it's basically a snake). Trains just bounce around forever.

Tap "p" to start pathfinding when focused on a line. This is just a demo and nothing uses this yet.

Configure

Some constants are in "src/shared.js", around units and so on.

Design

The Game class uses GraphType for its graph code, as well as SnakeMan to manage trains. Trains are basically snakes, and move by growing on one side and shrinking on another.

Graph

This is based on a generic GraphType interface (and Graph implementation in "src/graph.js") which contains edges and nodes.

• Each edge has at least two nodes (end nodes) and can be split by adding further nodes.

• These edges don't exist in physical space, and can be joined in non-euclidian ways, although do have physical length (as an integer).

• Nodes can be merged with other nodes (although they don't have to "pair"—think a line crossing over another).

  • They can be paired via Graph.join, which creates a path between them (in the game, this is where a red line appear to show connectivity).
  • Nodes will be on at least one edge, but perhaps multiple.

• There are some restrictions on graph operations for sanity.

  • Nodes cannot exist at multiple places on the same edge.
  • Edges can only be joined together at one place.
  • Because of this, it's possible to unambiguously match a segment via a request for two distinct nodes on the same edge.

Goals

The SVG renderer is really just a demo over the graph code. I have a personal goal to write a train game—while this might be used for casual games, I'm inspiring more from Factorio or similar in terms of the feature set.