Merge branch '2020-main'

1 files changed, 205 insertions, 0 deletions

diff --git a/2020/src/bin/day_3.rs b/2020/src/bin/day_3.rs
new file mode 100644
index 0000000..5e6f0bd
--- /dev/null
+++ b/2020/src/bin/day_3.rs
@@ -0,0 +1,205 @@
+use bevy::app::AppExit;
+use bevy::prelude::*;
+use bevy::render::camera::Camera;
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+
+fn main() {
+    App::build()
+        .add_resource(WindowDescriptor {
+            title: "Advent of Code".to_string(),
+            width: 1920,
+            height: 1080,
+            ..Default::default()
+        })
+        .add_resource(ClearColor(Color::rgb(0., 0., 0.)))
+        .add_startup_system(setup_camera.system())
+        .add_startup_stage("game_entities")
+        .add_startup_system_to_stage("game_entities", read_input_file.system())
+        .add_system(move_tobogganist.system())
+        .add_system(collide_with_trees.system())
+        .add_system(clear_finished_tobogganists.system())
+        .add_system(end_of_slope.system())
+        .add_system(translate_positions.system())
+        .add_system(tobogganist_cam.system())
+        .add_plugins(DefaultPlugins)
+        .run();
+}
+
+fn setup_camera(mut commands: Commands, mut materials: ResMut<Assets<ColorMaterial>>) {
+    commands.spawn(Camera2dComponents::default());
+
+    commands.insert_resource(Materials {
+        tobogganist_material: materials.add(Color::rgb(0., 0., 255.).into()),
+        tree_material: materials.add(Color::rgb(0., 255., 0.).into()),
+    });
+}
+
+struct Materials {
+    tobogganist_material: Handle<ColorMaterial>,
+    tree_material: Handle<ColorMaterial>,
+}
+
+struct Tobogganist;
+
+struct Tree;
+#[derive(PartialEq, Eq)]
+struct Position {
+    x: usize,
+    y: usize,
+}
+struct Velocity {
+    x: usize,
+    y: usize,
+}
+struct MapSize {
+    width: usize,
+    height: usize,
+}
+struct TreeHitCount(usize);
+struct Score(usize);
+
+fn read_input_file(mut commands: Commands, materials: Res<Materials>) {
+    commands
+        .spawn(SpriteComponents {
+            sprite: Sprite::new(Vec2::new(10., 10.)),
+            material: materials.tobogganist_material.clone(),
+            ..Default::default()
+        })
+        .with(Tobogganist)
+        .with(Position { x: 0, y: 0 })
+        .with(Velocity { x: 1, y: 1 })
+        .with(TreeHitCount(0));
+
+    commands
+        .spawn(SpriteComponents {
+            sprite: Sprite::new(Vec2::new(10., 10.)),
+            material: materials.tobogganist_material.clone(),
+            ..Default::default()
+        })
+        .with(Tobogganist)
+        .with(Position { x: 0, y: 0 })
+        .with(Velocity { x: 3, y: 1 })
+        .with(TreeHitCount(0));
+
+    commands
+        .spawn(SpriteComponents {
+            sprite: Sprite::new(Vec2::new(10., 10.)),
+            material: materials.tobogganist_material.clone(),
+            ..Default::default()
+        })
+        .with(Tobogganist)
+        .with(Position { x: 0, y: 0 })
+        .with(Velocity { x: 5, y: 1 })
+        .with(TreeHitCount(0));
+
+    commands
+        .spawn(SpriteComponents {
+            sprite: Sprite::new(Vec2::new(10., 10.)),
+            material: materials.tobogganist_material.clone(),
+            ..Default::default()
+        })
+        .with(Tobogganist)
+        .with(Position { x: 0, y: 0 })
+        .with(Velocity { x: 7, y: 1 })
+        .with(TreeHitCount(0));
+
+    commands
+        .spawn(SpriteComponents {
+            sprite: Sprite::new(Vec2::new(10., 10.)),
+            material: materials.tobogganist_material.clone(),
+            ..Default::default()
+        })
+        .with(Tobogganist)
+        .with(Position { x: 0, y: 0 })
+        .with(Velocity { x: 1, y: 2 })
+        .with(TreeHitCount(0));
+
+    let f = File::open("./inputs/day_3.txt").expect("Failed to read file"); // TODO: Use the asset loading system to load this rather?
+    let mut width = 0;
+    let mut height = 0;
+    for (y, line) in BufReader::new(f).lines().enumerate() {
+        let line = line.expect("Error reading file");
+        let line = line.trim();
+        width = width.max(line.len());
+        for (x, c) in line.chars().enumerate() {
+            if c == '#' {
+                commands
+                    .spawn(SpriteComponents {
+                        sprite: Sprite::new(Vec2::new(10., 10.)),
+                        material: materials.tree_material.clone(),
+                        ..Default::default()
+                    })
+                    .with(Tree)
+                    .with(Position { x, y })
+                    .with(TreeHitCount(0));
+            }
+        }
+        height = y + 1;
+    }
+    commands.insert_resource(MapSize { width, height });
+    commands.insert_resource(Score(1));
+}
+
+fn translate_positions(mut transform: Mut<Transform>, position: &Position) {
+    transform.translation = Vec3::new(position.x as f32 * 10., position.y as f32 * -10., 0.);
+}
+
+fn tobogganist_cam(
+    tobogganist: Query<With<Tobogganist, &Transform>>,
+    mut camera: Query<With<Camera, &mut Transform>>,
+) {
+    for mut camera_transform in camera.iter_mut() {
+        if let Some(tobogganist_transform) = tobogganist.iter().next() {
+            camera_transform.translation = Vec3::new(0., tobogganist_transform.translation.y(), 0.);
+        }
+    }
+}
+
+fn move_tobogganist(map_size: Res<MapSize>, mut position: Mut<Position>, velocity: &Velocity) {
+    position.x += velocity.x;
+    position.x %= map_size.width;
+    position.y += velocity.y;
+}
+
+fn collide_with_trees(
+    mut tobogganists: Query<With<Tobogganist, (&Position, &mut TreeHitCount)>>,
+    trees: Query<With<Tree, &Position>>,
+) {
+    for (tobogganist_position, mut tree_hit_count) in tobogganists.iter_mut() {
+        for tree_position in trees.iter() {
+            if *tree_position == *tobogganist_position {
+                tree_hit_count.0 += 1;
+            }
+        }
+    }
+}
+
+fn clear_finished_tobogganists(
+    mut commands: Commands,
+    map_size: Res<MapSize>,
+    mut score: ResMut<Score>,
+    tobogganists: Query<With<Tobogganist, (Entity, &Position, &Velocity, &TreeHitCount)>>,
+) {
+    for (entity, position, velocity, tree_hit_count) in tobogganists.iter() {
+        if position.y >= map_size.height {
+            println!(
+                "A tobogganist finished heading at incline {} x {}, after hitting {} trees",
+                velocity.x, velocity.y, tree_hit_count.0
+            );
+            score.0 *= tree_hit_count.0;
+            commands.despawn(entity);
+        }
+    }
+}
+
+fn end_of_slope(
+    score: Res<Score>,
+    mut exit_events: ResMut<Events<AppExit>>,
+    tobogganists: Query<&Tobogganist>,
+) {
+    if tobogganists.iter().count() == 0 {
+        println!("All tobogganists finished. Total score: {}", score.0);
+        exit_events.send(AppExit);
+    }
+}