Auto spawning creeps

Until now, we have created new creeps directly in the console. It’s not a good idea to do it constantly since the very idea of Screeps is making your colony control itself. You will do well if you teach your spawn to produce creeps in the room on its own.

This is a rather complicated topic and many players spend months perfecting and refining their auto-spawning code. But let’s try at least something simple and master some basic principles to start with.

You will have to create new creeps when old ones die from age or some other reasons. Since there are no events in the game to report death of a particular creep, the easiest way is to just count the number of required creeps, and if it becomes less than a defined value, to start spawning.

There are several ways to count the number of creeps of the required type. One of them is filtering Game.creeps with the help of the _.filter function and using the role in their memory. Let’s try to do that and bring the number of creeps into the console.

Add the output of the number of creeps with the role harvester into the console.

var roleHarvester = require('role.harvester');
var roleUpgrader = require('role.upgrader');

module.exports.loop = function () {

    var harvesters = _.filter(Game.creeps, (creep) => creep.memory.role == 'harvester');
    console.log('Harvesters: ' + harvesters.length);

    for(var name in Game.creeps) {
        var creep = Game.creeps[name];
        if(creep.memory.role == 'harvester') {
            roleHarvester.run(creep);
        }
    if(creep.memory.role == 'upgrader') {
        roleUpgrader.run(creep);
    }
}
}

Let’s say we want to have at least two harvesters at any time. The easiest way to achieve this is to run StructureSpawn.createCreep each time we discover it’s less than this number. You may not define its name (if will be given automatically in this case), but don’t forget to define the needed role.

Add the logic for StructureSpawn.createCreep in your main module.

var roleHarvester = require('role.harvester');
var roleUpgrader = require('role.upgrader');

module.exports.loop = function () {

var harvesters = _.filter(Game.creeps, (creep) => creep.memory.role == 'harvester');
console.log('Harvesters: ' + harvesters.length);

if(harvesters.length < 2) {
    var newName = Game.spawns.Spawn1.createCreep([WORK,CARRY,MOVE], undefined, {role: 'harvester'});
    console.log('Spawning new harvester: ' + newName);
}

for(var name in Game.creeps) {
    var creep = Game.creeps[name];
    if(creep.memory.role == 'harvester') {
        roleHarvester.run(creep);
    }
    if(creep.memory.role == 'upgrader') {
        roleUpgrader.run(creep);
    }
}
}

Now let’s try to emulate a situation when one of our harvesters dies. You can now give the command suicide to the creep via the console or its properties panel on the right.

Make one of the harvesters suicide.

Game.creeps.Harvester1.suicide()

As you can see from the console, after we lacked one harvester, the spawn instantly started building a new one with a new name.

An important point here is that the memory of dead creeps is not erased but kept for later reuse. If you create creeps with random names each time it may lead to memory overflow, so you should clear it in the beginning of each tick (prior to the creep creation code).

Add code to clear the memory.

var roleHarvester = require('role.harvester');
var roleUpgrader = require('role.upgrader');

module.exports.loop = function () {

for(var name in Memory.creeps) {
    if(!Game.creeps[name]) {
        delete Memory.creeps[name];
    }
}

var harvesters = _.filter(Game.creeps, (creep) => creep.memory.role == 'harvester');
console.log('Harvesters: ' + harvesters.length);

if(harvesters.length < 2) {
    var newName = Game.spawns.Spawn1.createCreep([WORK,CARRY,MOVE], undefined, {role: 'harvester'});
    console.log('Spawning new harvester: ' + newName);
}

for(var name in Game.creeps) {
    var creep = Game.creeps[name];
    if(creep.memory.role == 'harvester') {
        roleHarvester.run(creep);
    }
    if(creep.memory.role == 'upgrader') {
        roleUpgrader.run(creep);
    }
}
}

Now the memory of the deceased is relegated to oblivion which saves us resources.

Apart from creating new creeps after the death of old ones, there is another way to maintain the needed number of creeps: the method StructureSpawn.renewCreep. Creep aging is disabled in the Tutorial, so we recommend that you familiarize yourself with it on your own.

StructureSpawn.renewCreep

Increase the remaining time to live of the target creep. The target should be at adjacent square. The spawn should not be busy with the spawning process. Each execution increases the creep's timer by amount of ticks according to this formula: floor(600/body_size). Energy required for each execution is determined using this formula: ceil(creep_cost/2.5/body_size). Renewing a creep removes all of its boosts.

To make this more efficient there is another method StructureSpawn.canCreateCreep. this method has LOW cpu cost therefore it is better to check if the creep can be spawned before attempting a spawn and failing which is a CONST cpu cost (0.2).

var roleHarvester = require('role.harvester');
var roleUpgrader = require('role.upgrader');

module.exports.loop = function () {

for(var name in Memory.creeps) {
    if(!Game.creeps[name]) {
        delete Memory.creeps[name];
    }
}

var harvesters = _.filter(Game.creeps, (creep) => creep.memory.role == 'harvester');
console.log('Harvesters: ' + harvesters.length);
var upgraders = _.filter(Game.creeps, (creep) => creep.memory.role == 'upgrader');
console.log('Upgraders: ' + upgraders.length);
if (Game.spawns.Spawn1.canCreateCreep([WORK,CARRY,MOVE],undefined)== OK){
    console.log('Can create creep')
        if(harvesters.length < 5) {
    var newName = Game.spawns.Spawn1.createCreep([WORK,CARRY,MOVE], undefined, {role: 'harvester'});
    console.log('Spawning new harvester: ' + newName);
}
if(upgraders.length < 30) {
    var newName = Game.spawns.Spawn1.createCreep([WORK,CARRY,MOVE], undefined, {role: 'upgrader'});
    console.log('Spawning new upgrader: ' + newName);
}
}
for(var name in Game.creeps) {
    var creep = Game.creeps[name];
    if(creep.memory.role == 'harvester') {
        roleHarvester.run(creep);
    }
    if(creep.memory.role == 'upgrader') {
        roleUpgrader.run(creep);
    }
}
}