Remote Harvesting

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Remote harvesting is a strategy used by many players to harvest more energy than is available in the rooms they own. It involves sending creeps into a nearby room, either an unowned room or a Source Keeper room, and harvesting the energy from those rooms and bringing it back.

Restrictions

There are multiple obstacles with remote mining. These include gaining vision to the room, making sure your code supports multiple room pathing, hauling resources back from the remove rooms, the threat of invaders, and the logistics of reserving the room.

Strategies

Generic Long-range harvesters

The first and most basic of remote harvesting, generally generic body creeps or 'harvesters' can be allowed to either roam, or target adjacent rooms to look for more energy. On finding a source, they harvest their fill as their carry parts allow and return to their home room to use it on whatever task/goal/role they are assigned. While this can be a very easy method of gaining more energy than you could normally with the one-to-two sources provided in your default room, it does take your generic creeps outside the safety of your home room and, unless alot of creeps are involved it is hard to maximize the sources as time is required for the creeps to travel back and forth.

Miners & Haulers

The most common tactic for harvesting a nearby room for energy, each source is normally set up with a 'team' of two or more creeps, normally one 'miner' and one 'hauler'. The miner will spawn and path to its designated source or roomPosition and dedicate its life to harvesting energy solely from the source assigned, in the mean time a hauler or haulers will travel back and forth from the location being mined to ferry energy from where the miner has dropped it (or container that it is mining to) and return it to the main room for storage, use, ect. This tactic is very useful as you can maximize the amount of energy you get from the sources with less travel back and forth.

Reserving

Sources start out with 1500 energy in non-claimed or reserved rooms, so reserving them allows the sources to regenerate up to 3000 instead, allowing for more energy to be gained from the room. However, claim parts are expensive and so is having a creep constantly spam intents, which increases the more rooms you reserve. A creep with claim parts can reserve the controller in a proxy room (as long as it is not claimed) for one tick each claim part it has, and the 'reservation' will decay one each tick. The controller can have up to 5000 'reserved ticks' (effectively 4999 shown at any time), meaning you can have quite some time without a creep attending it. As claim (reserve) part creeps last only 600 ticks, balancing sending a creep to reserve and for how long, is important to both save energy & CPU.

Defense

As with any room you harvest energy in, around every 100,000 energy harvested, as long as there is one exit open to a neutral room invaders will attack. As creeps that harvest/transport/claim are normally non-combat creeps, and invaders by default live for 1500 ticks, simply letting them be can result in a large loss of energy. Effectively detecting, spawning and, deploying a combat creep to deal with the invaders automatically in a timely manner helps improve overall energy gains due to not needing downtime to avoid/respawn harvesting creeps.

With the advent of strongholds invaderCores can now spawn in rooms that are not owned by a user and start attacking/reserving a controller which can block your creeps from being able to harvest. As invaderCores are 'alien' technology and can not be dismantled by worker/harvester creeps, a creep needs to be dispatched to attack and remove the invaderCore. As some strongholds can spawn these quite often, dealing with them quickly and in a timely manner is critical.

Beyond NPC threats, other users can also disrupt your proxy harvesting. Other user's attacks tend to be more dynamic / threating so require some combat code to effectively deal with. But at base level, detecting the threat and responding to it is more or less the same as with an invader.

Source Keeper Rooms

Each 10x10 sector of the map contains 8 source keeper rooms in a ring around the center. These rooms have no controller, so they cannot be owned. However, they contain 3 sources each, and each source contains a maximum of 4000 energy rather than 3000. This makes them a good source of energy. They also contain a mineral, just like other rooms, with an extractor already built on top that allows for harvesting.

However, these rooms are guarded by non-player Source Keepers, which will attack creeps that try to harvest the sources. In addition, non-player Invaders will appear in greater numbers with increased frequency and strength. Extra precautions must be taken to ensure the safety of your harvesters.