This tutorial is free and open source, and all code uses the MIT license - so you are free to do with it as you like. My hope is that you will enjoy the tutorial, and make great games!

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Adding a colonist

A central theme of SecBot is locating the colonists who live in and around the mining facility. That makes adding them a top priority! So I started day #2 by trying to do just that.

Create a Colonist Tag

There needs to be a way to indicate that an Entity is a Colonist. The easy way to accomplish this is with another tag component - a component that doesn't contain data, but just indicates a flag is set by existing.

Open components/tag.rs and add the following tag component:

#![allow(unused)]
fn main() {
pub struct Colonist;
}

Spawning Colonists

We're going to be adding colonists all over the map. We'll eventually have some variation in colonists, too. Let's create a new module to hold the colonist spawning logic. Create a new file: src/map/layerbuilder/colonists.rs. Paste the following into it:

#![allow(unused)]
fn main() {
use bracket_lib::prelude::*;
use legion::*;
use crate::components::*;

pub fn spawn_random_colonist(ecs: &mut World, location: Point, layer: u32) {
    ecs.push((
        Colonist{},
        Position::with_pt(location, layer),
        Glyph{ glyph: to_cp437('☺'), color: ColorPair::new( LIME_GREEN, BLACK ) },
        Description("A squishy friend. You are here to rescue your squishies.".to_string())
    ));
}
}

This should look familar. It pushes a new entity, and gives them a Colonist tag as well as a Position (where they are on the map), a Glyph (how to render them), and a Description for tool-tips.

Activate the module and make it available by adding mod colonists; use colonists::*; to src/map/layerbuilder/mod.rs.

Adding the First Colonist

Open layerbuilder/entrance.rs. Add an import for the spawn_random_colonist function, modifying the previous use super::all_space import.

#![allow(unused)]
fn main() {
use super::{all_space, spawn_random_colonist};
}

Now scroll down to where we call add_exit in the add_docking_capsule function. Immediately after add_exit(...), add the following:

#![allow(unused)]
fn main() {
// Populate rooms
populate_rooms(&mut rooms, map, ecs);
}

Then, at the end of entrance.rs add the following function:

#![allow(unused)]
fn main() {
fn populate_rooms(rooms: &mut Vec<Rect>, map: &mut Layer, ecs: &mut World) {
    // The first room always contains a single colonist
    spawn_random_colonist(ecs, rooms[0].center(), 0);

    // Each room after that can be random
}
}

Give it a Go

The entry room now contains a colonist! They don't do anything other than exist and have a tool-tip, but it's good to see that the entity/component system we setup is working.

You can find the source code for hello_colonist here.

Up Next

In the next section, we'll be adding more colonists - and adding some UI to count them, and categorize their status.