Add chapter 2.6

src/components.rs

@@ -17,3 +17,52 @@ pub struct Renderable {
 
 #[derive(Component, Debug)]
 pub struct Player {}
+
+#[derive(Component)]
+pub struct Viewshed {
+    pub visible_tiles: Vec<rltk::Point>,
+    pub range: i32,
+    pub dirty: bool,
+}
+
+#[derive(Component)]
+pub struct Monster {}
+
+#[derive(Component, Debug)]
+pub struct Name {
+    pub name: String,
+}
+
+#[derive(Component, Debug)]
+pub struct BlocksTile {}
+
+#[derive(Component, Debug)]
+pub struct CombatStats {
+    pub max_hp: i32,
+    pub hp: i32,
+    pub defense: i32,
+    pub power: i32,
+}
+
+#[derive(Component, Debug, Clone)]
+pub struct WantsToMelee {
+    pub target: Entity,
+}
+
+#[derive(Component, Debug)]
+pub struct SufferDamage {
+    pub amount: Vec<i32>,
+}
+
+impl SufferDamage {
+    pub fn new_damage(store: &mut WriteStorage<SufferDamage>, victim: Entity, amount: i32) {
+        if let Some(suffering) = store.get_mut(victim) {
+            suffering.amount.push(amount);
+        } else {
+            let dmg = SufferDamage {
+                amount: vec![amount],
+            };
+            store.insert(victim, dmg).expect("Unable to insert damage");
+        }
+    }
+}

src/damage_system.rs

@@ -0,0 +1,45 @@
+use rltk::console;
+use specs::prelude::*;
+
+use crate::components::{CombatStats, Player, SufferDamage};
+
+pub struct DamageSystem {}
+
+impl<'a> System<'a> for DamageSystem {
+    type SystemData = (
+        WriteStorage<'a, CombatStats>,
+        WriteStorage<'a, SufferDamage>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (mut stats, mut damage) = data;
+
+        for (mut stats, damage) in (&mut stats, &damage).join() {
+            stats.hp -= damage.amount.iter().sum::<i32>();
+        }
+
+        damage.clear();
+    }
+}
+
+pub fn delete_the_dead(ecs: &mut World) {
+    let mut dead: Vec<Entity> = Vec::new();
+    {
+        let combat_stats = ecs.read_storage::<CombatStats>();
+        let players = ecs.read_storage::<Player>();
+        let entities = ecs.entities();
+        for (entity, stats) in (&entities, &combat_stats).join() {
+            if stats.hp < 1 {
+                let player = players.get(entity);
+                match player {
+                    None => dead.push(entity),
+                    Some(_) => console::log("You are dead"),
+                }
+            }
+        }
+    }
+
+    for victim in dead {
+        ecs.delete_entity(victim).expect("Unable to delete");
+    }
+}

src/main.rs

@@ -1,20 +1,54 @@
 use components::*;
+use damage_system::DamageSystem;
 use map::*;
+use map_indexing_system::MapIndexingSystem;
+use melee_combat_system::MeleeCombatSystem;
+use monster_ai_system::*;
 use player::*;
-use rltk::{GameState, RGB};
+use rltk::{GameState, Point, RGB};
+use visibility_system::*;
 
 use specs::prelude::*;
 
 mod components;
+mod damage_system;
 mod map;
+mod map_indexing_system;
+mod melee_combat_system;
+mod monster_ai_system;
 mod player;
+mod rect;
+mod visibility_system;
+
+#[derive(PartialEq, Copy, Clone)]
+pub enum RunState {
+    AwaitingInput,
+    PreRun,
+    PlayerTurn,
+    MonsterTurn,
+}
 
 pub struct State {
-    ecs: World,
+    pub ecs: World,
 }
 
 impl State {
     fn run_systems(&mut self) {
+        let mut vis = VisibilitySystem {};
+        vis.run_now(&self.ecs);
+
+        let mut mob = MonsterAI {};
+        mob.run_now(&self.ecs);
+
+        let mut mapindex = MapIndexingSystem {};
+        mapindex.run_now(&self.ecs);
+
+        let mut meleesystem = MeleeCombatSystem {};
+        meleesystem.run_now(&self.ecs);
+
+        let mut damagesystem = DamageSystem {};
+        damagesystem.run_now(&self.ecs);
+
         self.ecs.maintain();
     }
 }
@@ -23,20 +57,48 @@ impl GameState for State {
     fn tick(&mut self, ctx: &mut rltk::Rltk) {
         ctx.cls();
 
-        player_input(self, ctx);
-        self.run_systems();
+        let mut newrunstate;
+        {
+            let runstate = self.ecs.fetch::<RunState>();
+            newrunstate = *runstate;
+        }
 
-        let map = self.ecs.fetch::<Vec<TileType>>();
-        draw_map(&map, ctx);
+        match newrunstate {
+            RunState::PreRun => {
+                self.run_systems();
+                newrunstate = RunState::AwaitingInput;
+            }
+            RunState::AwaitingInput => newrunstate = player_input(self, ctx),
+            RunState::PlayerTurn => {
+                self.run_systems();
+                newrunstate = RunState::MonsterTurn;
+            }
+            RunState::MonsterTurn => {
+                self.run_systems();
+                newrunstate = RunState::AwaitingInput;
+            }
+        }
+
+        {
+            let mut runwriter = self.ecs.write_resource::<RunState>();
+            *runwriter = newrunstate;
+        }
+        damage_system::delete_the_dead(&mut self.ecs);
+
+        draw_map(&self.ecs, ctx);
 
         let positions = self.ecs.read_storage::<Position>();
         let renderables = self.ecs.read_storage::<Renderable>();
+        let map = self.ecs.fetch::<Map>();
 
         for (pos, render) in (&positions, &renderables).join() {
+            let idx = map.xy_idx(pos.x, pos.y);
+            if map.visible_tiles[idx] {
                 ctx.set(pos.x, pos.y, render.fg, render.bg, render.glyph)
             }
         }
     }
+}
 
 fn main() -> rltk::BError {
     use rltk::RltkBuilder;
@@ -47,21 +109,98 @@ fn main() -> rltk::BError {
         .build()?;
     let mut gs = State { ecs: World::new() };
 
+    gs.ecs.insert(RunState::PreRun);
+
     gs.ecs.register::<Position>();
     gs.ecs.register::<Renderable>();
     gs.ecs.register::<Player>();
-    gs.ecs.insert(new_map_rooms_and_corridors());
+    gs.ecs.register::<Viewshed>();
+    gs.ecs.register::<Monster>();
+    gs.ecs.register::<Name>();
+    gs.ecs.register::<BlocksTile>();
+    gs.ecs.register::<CombatStats>();
+    gs.ecs.register::<WantsToMelee>();
+    gs.ecs.register::<SufferDamage>();
+    let map = Map::new_map_rooms_and_corridors();
+    let (player_x, player_y) = map.rooms[0].center();
 
-    gs.ecs
+    gs.ecs.insert(Point::new(player_x, player_y));
+    let player_entity = gs
+        .ecs
         .create_entity()
-        .with(Position { x: 40, y: 25 })
+        .with(Position {
+            x: player_x,
+            y: player_y,
+        })
         .with(Renderable {
             glyph: rltk::to_cp437('@'),
             fg: RGB::named(rltk::YELLOW),
             bg: RGB::named(rltk::BLACK),
         })
         .with(Player {})
+        .with(Viewshed {
+            visible_tiles: Vec::new(),
+            range: 8,
+            dirty: true,
+        })
+        .with(Name {
+            name: "Player".to_string(),
+        })
+        .with(CombatStats {
+            max_hp: 30,
+            hp: 30,
+            defense: 2,
+            power: 5,
+        })
         .build();
 
+    gs.ecs.insert(player_entity);
+
+    let mut rng = rltk::RandomNumberGenerator::new();
+    for (i, room) in map.rooms.iter().skip(1).enumerate() {
+        let (x, y) = room.center();
+        let glyph: rltk::FontCharType;
+        let roll = rng.roll_dice(1, 2);
+        let name: String;
+        match roll {
+            1 => {
+                glyph = rltk::to_cp437('g');
+                name = "Goblin".to_string();
+            }
+            _ => {
+                glyph = rltk::to_cp437('o');
+                name = "Orc".to_string();
+            }
+        }
+
+        gs.ecs
+            .create_entity()
+            .with(Position { x, y })
+            .with(Renderable {
+                glyph,
+                fg: RGB::named(rltk::RED),
+                bg: RGB::named(rltk::BLACK),
+            })
+            .with(Viewshed {
+                visible_tiles: Vec::new(),
+                range: 8,
+                dirty: true,
+            })
+            .with(Monster {})
+            .with(Name {
+                name: format!("{} #{}", &name, i),
+            })
+            .with(BlocksTile {})
+            .with(CombatStats {
+                max_hp: 16,
+                hp: 16,
+                defense: 1,
+                power: 4,
+            })
+            .build();
+    }
+
+    gs.ecs.insert(map);
+
     rltk::main_loop(context, gs)
 }

src/map.rs

@@ -1,4 +1,9 @@
-use rltk::{Rltk, RGB};
+use std::cmp::{max, min};
+
+use rltk::{Algorithm2D, BaseMap, Point, RandomNumberGenerator, Rltk, RGB};
+use specs::prelude::*;
+
+use crate::rect::Rect;
 
 #[derive(PartialEq, Copy, Clone)]
 pub enum TileType {
@@ -6,69 +11,201 @@ pub enum TileType {
     Floor,
 }
 
-pub fn xy_idx(x: i32, y: i32) -> usize {
-    (y as usize * 80) + x as usize
+pub struct Map {
+    pub tiles: Vec<TileType>,
+    pub rooms: Vec<Rect>,
+    pub width: i32,
+    pub height: i32,
+    pub revealed_tiles: Vec<bool>,
+    pub visible_tiles: Vec<bool>,
+    pub blocked: Vec<bool>,
+    pub tile_content: Vec<Vec<Entity>>,
 }
 
-pub fn new_map_rooms_and_corridors() -> Vec<TileType> {
-    let mut map = vec![TileType::Wall; 80 * 50];
-
-    map
+impl Map {
+    pub fn xy_idx(&self, x: i32, y: i32) -> usize {
+        (y as usize * self.width as usize) + x as usize
     }
 
-/// Makes a map with solid boundaries and 400 randomly placed walls. No guarantees that it won't look awful
-pub fn new_map_test() -> Vec<TileType> {
-    let mut map = vec![TileType::Floor; 80 * 50];
-
-    for x in 0..80 {
-        map[xy_idx(x, 0)] = TileType::Wall;
-        map[xy_idx(x, 49)] = TileType::Wall;
+    fn apply_room_to_map(&mut self, room: &Rect) {
+        for y in room.y1 + 1..=room.y2 {
+            for x in room.x1 + 1..=room.x2 {
+                let idx = self.xy_idx(x, y);
+                self.tiles[idx] = TileType::Floor;
+            }
+        }
     }
 
-    for y in 0..50 {
-        map[xy_idx(0, y)] = TileType::Wall;
-        map[xy_idx(79, y)] = TileType::Wall;
+    fn apply_horizontal_tunnel(&mut self, x1: i32, x2: i32, y: i32) {
+        for x in min(x1, x2)..=max(x1, x2) {
+            let idx = self.xy_idx(x, y);
+            if idx > 0 && idx < self.width as usize * self.height as usize {
+                self.tiles[idx as usize] = TileType::Floor;
+            }
+        }
     }
 
-    let mut rng = rltk::RandomNumberGenerator::new();
+    fn apply_vertical_tunnel(&mut self, y1: i32, y2: i32, x: i32) {
+        for y in min(y1, y2)..=max(y1, y2) {
+            let idx = self.xy_idx(x, y);
+            if idx > 0 && idx < self.width as usize * self.height as usize {
+                self.tiles[idx as usize] = TileType::Floor;
+            }
+        }
+    }
 
-    for _i in 0..400 {
-        let x = rng.roll_dice(1, 79);
-        let y = rng.roll_dice(1, 49);
-        let idx = xy_idx(x, y);
-        if idx != xy_idx(40, 25) {
-            map[idx] = TileType::Wall;
+    pub fn new_map_rooms_and_corridors() -> Map {
+        let mut map = Map {
+            tiles: vec![TileType::Wall; 80 * 50],
+            rooms: Vec::new(),
+            width: 80,
+            height: 50,
+            revealed_tiles: vec![false; 80 * 50],
+            visible_tiles: vec![false; 80 * 50],
+            blocked: vec![false; 80 * 50],
+            tile_content: vec![Vec::new(); 80 * 50],
+        };
+
+        const MAX_ROOMS: i32 = 30;
+        const MIN_SIZE: i32 = 6;
+        const MAX_SIZE: i32 = 10;
+
+        let mut rng = RandomNumberGenerator::new();
+
+        for _ in 0..MAX_ROOMS {
+            let w = rng.range(MIN_SIZE, MAX_SIZE);
+            let h = rng.range(MIN_SIZE, MAX_SIZE);
+            let x = rng.roll_dice(1, map.width - w - 1) - 1;
+            let y = rng.roll_dice(1, map.height - h - 1) - 1;
+            let new_room = Rect::new(x, y, w, h);
+            let mut ok = true;
+            for other_room in map.rooms.iter() {
+                if new_room.intersect(other_room) {
+                    ok = false
+                };
+            }
+            if ok {
+                map.apply_room_to_map(&new_room);
+
+                if !map.rooms.is_empty() {
+                    let (new_x, new_y) = new_room.center();
+                    let (prev_x, prev_y) = map.rooms[map.rooms.len() - 1].center();
+                    if rng.range(0, 2) == 1 {
+                        map.apply_horizontal_tunnel(prev_x, new_x, prev_y);
+                        map.apply_vertical_tunnel(prev_y, new_y, new_x);
+                    } else {
+                        map.apply_vertical_tunnel(prev_y, new_y, prev_x);
+                        map.apply_horizontal_tunnel(prev_x, new_x, new_y);
+                    }
+                }
+
+                map.rooms.push(new_room);
             }
         }
 
         map
     }
 
-pub fn draw_map(map: &[TileType], ctx: &mut Rltk) {
+    fn is_exit_valid(&self, x: i32, y: i32) -> bool {
+        if x < 1 || x > self.width - 1 || y < 1 || y > self.height - 1 {
+            return false;
+        }
+        let idx = self.xy_idx(x, y);
+        !self.blocked[idx]
+    }
+
+    pub fn populate_blocked(&mut self) {
+        for (i, tile) in self.tiles.iter_mut().enumerate() {
+            self.blocked[i] = *tile == TileType::Wall;
+        }
+    }
+
+    pub fn clear_content_index(&mut self) {
+        for content in self.tile_content.iter_mut() {
+            content.clear();
+        }
+    }
+}
+
+impl Algorithm2D for Map {
+    fn dimensions(&self) -> rltk::Point {
+        Point::new(self.width, self.height)
+    }
+}
+
+impl BaseMap for Map {
+    fn is_opaque(&self, idx: usize) -> bool {
+        self.tiles[idx as usize] == TileType::Wall
+    }
+
+    fn get_pathing_distance(&self, idx1: usize, idx2: usize) -> f32 {
+        let w = self.width as usize;
+        let p1 = Point::new(idx1 % w, idx1 / w);
+        let p2 = Point::new(idx2 % w, idx2 / w);
+        rltk::DistanceAlg::Pythagoras.distance2d(p1, p2)
+    }
+
+    fn get_available_exits(&self, idx: usize) -> rltk::SmallVec<[(usize, f32); 10]> {
+        let mut exits = rltk::SmallVec::new();
+        let x = idx as i32 % self.width;
+        let y = idx as i32 / self.width;
+        let w = self.width as usize;
+
+        if self.is_exit_valid(x - 1, y) {
+            exits.push((idx - 1, 1.0))
+        };
+        if self.is_exit_valid(x + 1, y) {
+            exits.push((idx + 1, 1.0))
+        };
+        if self.is_exit_valid(x, y - 1) {
+            exits.push((idx - w, 1.0))
+        };
+        if self.is_exit_valid(x, y + 1) {
+            exits.push((idx + w, 1.0))
+        };
+
+        if self.is_exit_valid(x - 1, y - 1) {
+            exits.push((idx - w - 1, 1.45))
+        };
+        if self.is_exit_valid(x + 1, y - 1) {
+            exits.push((idx - w + 1, 1.45))
+        };
+        if self.is_exit_valid(x - 1, y + 1) {
+            exits.push((idx + w - 1, 1.45))
+        };
+        if self.is_exit_valid(x + 1, y + 1) {
+            exits.push((idx + w + 1, 1.45))
+        };
+
+        exits
+    }
+}
+
+pub fn draw_map(ecs: &World, ctx: &mut Rltk) {
+    let map = ecs.fetch::<Map>();
+
     let mut y = 0;
     let mut x = 0;
-    for tile in map.iter() {
+    for (idx, tile) in map.tiles.iter().enumerate() {
+        if map.revealed_tiles[idx] {
+            let glyph;
+            let mut fg;
             match tile {
                 TileType::Floor => {
-                ctx.set(
-                    x,
-                    y,
-                    RGB::from_f32(0.5, 0.5, 0.5),
-                    RGB::from_f32(0., 0., 0.),
-                    rltk::to_cp437('.'),
-                );
+                    fg = RGB::from_f32(0.5, 0.5, 0.5);
+                    glyph = rltk::to_cp437('.');
                 }
 
                 TileType::Wall => {
-                ctx.set(
-                    x,
-                    y,
-                    RGB::from_f32(0.0, 1.0, 0.0),
-                    RGB::from_f32(0., 0., 0.),
-                    rltk::to_cp437('#'),
-                );
+                    fg = RGB::from_f32(0.0, 1.0, 0.0);
+                    glyph = rltk::to_cp437('#');
                 }
             }
+            if !map.visible_tiles[idx] {
+                fg = fg.to_greyscale()
+            }
+            ctx.set(x, y, fg, RGB::from_f32(0., 0., 0.), glyph);
+        }
 
         x += 1;
         if x > 79 {

src/map_indexing_system.rs

@@ -0,0 +1,34 @@
+use specs::prelude::*;
+
+use crate::{
+    components::{BlocksTile, Position},
+    map::Map,
+};
+
+pub struct MapIndexingSystem {}
+
+impl<'a> System<'a> for MapIndexingSystem {
+    type SystemData = (
+        WriteExpect<'a, Map>,
+        ReadStorage<'a, Position>,
+        ReadStorage<'a, BlocksTile>,
+        Entities<'a>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (mut map, position, blockers, entities) = data;
+
+        map.populate_blocked();
+        map.clear_content_index();
+        for (entity, position) in (&entities, &position).join() {
+            let idx = map.xy_idx(position.x, position.y);
+
+            let _p: Option<&BlocksTile> = blockers.get(entity);
+            if let Some(_p) = _p {
+                map.blocked[idx] = true;
+            }
+
+            map.tile_content[idx].push(entity);
+        }
+    }
+}

src/melee_combat_system.rs

@@ -0,0 +1,48 @@
+use rltk::console;
+use specs::prelude::*;
+
+use crate::components::{CombatStats, Name, SufferDamage, WantsToMelee};
+
+pub struct MeleeCombatSystem {}
+
+impl<'a> System<'a> for MeleeCombatSystem {
+    type SystemData = (
+        Entities<'a>,
+        WriteStorage<'a, WantsToMelee>,
+        ReadStorage<'a, Name>,
+        ReadStorage<'a, CombatStats>,
+        WriteStorage<'a, SufferDamage>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (entities, mut wants_melee, names, combat_stats, mut inflict_damage) = data;
+
+        for (_entity, wants_melee, name, stats) in
+            (&entities, &wants_melee, &names, &combat_stats).join()
+        {
+            if stats.hp > 0 {
+                let target_stats = combat_stats.get(wants_melee.target).unwrap();
+                if target_stats.hp > 0 {
+                    let target_name = names.get(wants_melee.target).unwrap();
+
+                    let damage = i32::max(0, stats.power - target_stats.defense);
+
+                    if damage == 0 {
+                        console::log(&format!(
+                            "{} is unable to hurt {}",
+                            &name.name, &target_name.name
+                        ));
+                    } else {
+                        console::log(&format!(
+                            "{} hits {}, for {} hp.",
+                            &name.name, &target_name.name, damage
+                        ));
+                        SufferDamage::new_damage(&mut inflict_damage, wants_melee.target, damage)
+                    }
+                }
+            }
+        }
+
+        wants_melee.clear();
+    }
+}

src/monster_ai_system.rs

@@ -0,0 +1,75 @@
+use rltk::{console, Point};
+use specs::prelude::*;
+
+use crate::{
+    components::{Monster, Position, Viewshed, WantsToMelee},
+    map::Map,
+    RunState,
+};
+
+pub struct MonsterAI {}
+
+impl<'a> System<'a> for MonsterAI {
+    #[allow(clippy::type_complexity)]
+    type SystemData = (
+        WriteExpect<'a, Map>,
+        ReadExpect<'a, Point>,
+        ReadExpect<'a, Entity>,
+        ReadExpect<'a, RunState>,
+        Entities<'a>,
+        WriteStorage<'a, Viewshed>,
+        ReadStorage<'a, Monster>,
+        WriteStorage<'a, Position>,
+        WriteStorage<'a, WantsToMelee>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (
+            mut map,
+            player_pos,
+            player_entity,
+            runstate,
+            entities,
+            mut viewshed,
+            monster,
+            mut position,
+            mut wants_to_melee,
+        ) = data;
+
+        if *runstate != RunState::MonsterTurn {
+            return;
+        }
+
+        for (entity, mut viewshed, _monster, mut pos) in
+            (&entities, &mut viewshed, &monster, &mut position).join()
+        {
+            let distance =
+                rltk::DistanceAlg::Pythagoras.distance2d(Point::new(pos.x, pos.y), *player_pos);
+            if distance < 1.5 {
+                wants_to_melee
+                    .insert(
+                        entity,
+                        WantsToMelee {
+                            target: *player_entity,
+                        },
+                    )
+                    .expect("Unable to insert attack");
+            } else if viewshed.visible_tiles.contains(&*player_pos) {
+                let path = rltk::a_star_search(
+                    map.xy_idx(pos.x, pos.y) as i32,
+                    map.xy_idx(player_pos.x, player_pos.y) as i32,
+                    &mut *map,
+                );
+                if path.success && path.steps.len() > 1 {
+                    let mut idx = map.xy_idx(pos.x, pos.y);
+                    map.blocked[idx] = false;
+                    pos.x = path.steps[1] as i32 % map.width;
+                    pos.y = path.steps[1] as i32 / map.width;
+                    idx = map.xy_idx(pos.x, pos.y);
+                    map.blocked[idx] = true;
+                    viewshed.dirty = true;
+                }
+            }
+        }
+    }
+}

src/player.rs

@@ -1,35 +1,67 @@
 use crate::{
-    components::{Player, Position},
-    map::{xy_idx, TileType},
-    State,
+    components::{CombatStats, Player, Position, Viewshed, WantsToMelee},
+    map::{Map, TileType},
+    RunState, State,
 };
-use rltk::Rltk;
+use rltk::{console, Point, Rltk, VirtualKeyCode};
 use specs::prelude::*;
 use std::cmp::{max, min};
 
 pub fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut positions = ecs.write_storage::<Position>();
     let mut players = ecs.write_storage::<Player>();
-    let map = ecs.fetch::<Vec<TileType>>();
+    let mut viewsheds = ecs.write_storage::<Viewshed>();
+    let combat_stats = ecs.read_storage::<CombatStats>();
+    let entities = ecs.entities();
+    let mut wants_to_melee = ecs.write_storage::<WantsToMelee>();
+    let map = ecs.fetch::<Map>();
 
-    for (_player, pos) in (&mut players, &mut positions).join() {
-        let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
-        if map[destination_idx] != TileType::Wall {
+    for (entity, _player, pos, viewshed) in
+        (&entities, &mut players, &mut positions, &mut viewsheds).join()
+    {
+        let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
+
+        for potential_target in map.tile_content[destination_idx].iter() {
+            let target = combat_stats.get(*potential_target);
+            if let Some(_target) = target {
+                wants_to_melee
+                    .insert(
+                        entity,
+                        WantsToMelee {
+                            target: *potential_target,
+                        },
+                    )
+                    .expect("Add target failed");
+            }
+        }
+
+        if !map.blocked[destination_idx] {
             pos.x = min(79, max(0, pos.x + delta_x));
             pos.y = min(49, max(0, pos.y + delta_y));
+
+            viewshed.dirty = true;
+            let mut ppos = ecs.write_resource::<Point>();
+            ppos.x = pos.x;
+            ppos.y = pos.y;
         }
     }
 }
 
-pub fn player_input(gs: &mut State, ctx: &mut Rltk) {
+pub fn player_input(gs: &mut State, ctx: &mut Rltk) -> RunState {
     match ctx.key {
-        None => {}
+        None => return RunState::AwaitingInput,
         Some(key) => match key {
-            rltk::VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
-            rltk::VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
-            rltk::VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
-            rltk::VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            _ => {}
+            VirtualKeyCode::Left | VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Right | VirtualKeyCode::L => try_move_player(1, 0, &mut gs.ecs),
+            VirtualKeyCode::Up | VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Down | VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Y => try_move_player(1, -1, &mut gs.ecs),
+            VirtualKeyCode::U => try_move_player(-1, -1, &mut gs.ecs),
+            VirtualKeyCode::N => try_move_player(1, 1, &mut gs.ecs),
+            VirtualKeyCode::B => try_move_player(-1, 1, &mut gs.ecs),
+            _ => return RunState::AwaitingInput,
         },
     }
+
+    RunState::PlayerTurn
 }

src/rect.rs

@@ -0,0 +1,25 @@
+pub struct Rect {
+    pub x1: i32,
+    pub x2: i32,
+    pub y1: i32,
+    pub y2: i32,
+}
+
+impl Rect {
+    pub fn new(x: i32, y: i32, w: i32, h: i32) -> Self {
+        Self {
+            x1: x,
+            y1: y,
+            x2: x + w,
+            y2: y + h,
+        }
+    }
+
+    pub fn intersect(&self, other: &Rect) -> bool {
+        self.x1 <= other.x2 && self.x2 >= other.x1 && self.y1 <= other.y2 && self.y2 >= other.y1
+    }
+
+    pub fn center(&self) -> (i32, i32) {
+        ((self.x1 + self.x2) / 2, (self.y1 + self.y2) / 2)
+    }
+}

src/visibility_system.rs

@@ -0,0 +1,47 @@
+use rltk::{field_of_view, Point};
+use specs::prelude::*;
+
+use crate::{
+    components::{Player, Position, Viewshed},
+    map::Map,
+};
+
+pub struct VisibilitySystem {}
+
+impl<'a> System<'a> for VisibilitySystem {
+    type SystemData = (
+        WriteExpect<'a, Map>,
+        Entities<'a>,
+        WriteStorage<'a, Viewshed>,
+        WriteStorage<'a, Position>,
+        ReadStorage<'a, Player>,
+    );
+
+    fn run(&mut self, data: Self::SystemData) {
+        let (mut map, entities, mut viewshed, pos, player) = data;
+        for (ent, viewshed, pos) in (&entities, &mut viewshed, &pos).join() {
+            if !viewshed.dirty {
+                return;
+            }
+
+            viewshed.dirty = false;
+            viewshed.visible_tiles.clear();
+            viewshed.visible_tiles = field_of_view(Point::new(pos.x, pos.y), viewshed.range, &*map);
+            viewshed
+                .visible_tiles
+                .retain(|p| p.x >= 0 && p.x < map.width && p.y >= 0 && p.y < map.height);
+
+            let p: Option<&Player> = player.get(ent);
+            if let Some(_p) = p {
+                for t in map.visible_tiles.iter_mut() {
+                    *t = false
+                }
+                for vis in viewshed.visible_tiles.iter() {
+                    let idx = map.xy_idx(vis.x, vis.y);
+                    map.revealed_tiles[idx] = true;
+                    map.visible_tiles[idx] = true;
+                }
+            }
+        }
+    }
+}