Automated extraction in your game (resource.extraction) #

What it is for #

resource.extraction connects a machine to the resource node it stands on: a drill on an ore vein, a pump on a spring, a harvester on a crystal field. A machine of machines.production that carries the extractor component and is placed on (or near) a node marked extractable draws one gather from it each cycle instead of needing inputs, and fills its own output store. Neither the machine rules nor the node rules change: the node runs out and grows back by its own rules, or never runs out. Good for factory, survival, colony and idle games.

Turn it on #

gripforge_gamekit_install   { project_id: "gkp_…", id: "resource.extraction" }
gripforge_gamekit_configure { project_id: "gkp_…", id: "resource.extraction",
                              config: { "radius": 2, "infinite": false } }

It requires machines.production, resource.nodes and game.engine. It has no screen of its own. Targets: web and the Rust kit host.

First example #

<!-- test: kits/game_engine/host/tests/resource_extraction.rs::an_extractor_draws_from_the_node_it_stands_on --> A node that is extractable, a machine, and a buildable that carries the component:

{ "resource_nodes": [ { "id": "iron_vein", "name": "Iron vein", "item": "iron_ore", "uses": 20, "respawnSeconds": 120, "extractable": true } ],
  "machines": [ { "id": "drill", "name": "Drill", "seconds": 6 } ],
  "buildables": [ { "id": "drill", "name": "Drill", "cost": [{ "item": "plate", "count": 4 }],
                   "components": { "machine": { "machine": "drill" }, "extractor": { "rate": 1 } } } ] }

In the test, a drill with attach(drill, 2) standing near a vein of 2 uses (2 ore per gather) draws two gathers at rate 2, so its output store holds 8 ore, then the vein runs out. The nearer bush is ignored because it is not extractable, and attach on it answers false. After the vein grows back the drill starts again, and the link survives a save and load.

Rules #

• Who: a machine that carries the component extractor ({ rate? }), through a buildable's components, an archetype, a spawn, or attach.
• Where: the nearest free node within radius whose document says extractable: true and that has uses left. One machine per node. A machine with no node waits (inputs) and draws no power.
• What: each machine cycle draws one gather (the node item, count times rate units) into the output store. The machine waits while the node has nothing or while its store is full.
• The node loses one use per cycle, runs out and grows back by its own rules (respawnSeconds); the machine starts again when it does. The kit sweeps four times a second for nodes.

Settings and defaults #

The component extractor takes rate (0.01 to 1000, default 1): a multiplier of the units drawn per cycle.

Service, events and hooks #

Service resource.extraction:

• extractors(): [{ machine, node, item, rate }], the current links.
• attach(machine, rate?): makes a machine an extractor; false when it is not a machine.

The kit listens to entity.spawned and entity.despawned. The links are saved: a load goes on without announcing them again.

Hooks and modding #

{ "id": "deep_drills", "hook": "extraction.extract", "match": { "nodeId": "iron_vein" }, "mul": { "rate": 2 } }

A mod may override radius and infinite. The yield of the node itself is the hook resource.extract of resource.nodes (see Resource nodes).

When it does not do what you expect #

• The machine never works: no node within radius, the node is not extractable, or it has no uses left (it waits, drawing no power).
• Two drills on one vein: only one links; the other waits.
• The player still depletes a node with infinite on: that setting only protects it from extractors.
• extraction.stopped with far: the machine or the node moved away.

Limits #

• It draws only from resource.nodes; the machine must belong to machines.production.
• One machine per node, one gather per cycle.

Versions #

Kit 1.2.0; service resource.extraction 1.0.0. Hooks and moddable config since 1.1.0; since 1.2.0 a refused link is saved with the game.