First good iteration of field of view

src/components.rs

@@ -1,6 +1,6 @@
+use rltk::RGB;
 use specs::prelude::*;
 use specs_derive::*;
-use rltk::{RGB};
 
 #[derive(Component)]
 pub struct Position {
@@ -17,3 +17,9 @@ pub struct Renderable {
 
 #[derive(Component, Debug)]
 pub struct Player {}
+
+#[derive(Component)]
+pub struct Viewshed {
+    pub visible_tiles: Vec<rltk::Point>,
+    pub range: i32,
+}

src/main.rs

@@ -8,6 +8,9 @@ pub use map::*;
 mod player;
 use player::*;
 mod rect;
+mod visibility_system;
+use visibility_system::VisibilitySystem;
+
 pub use rect::Rect;
 
 pub struct State {
@@ -16,6 +19,9 @@ pub struct State {
 
 impl State {
     fn run_systems(&mut self) {
+        let mut vis = VisibilitySystem {};
+        vis.run_now(&self.ecs);
+
         self.ecs.maintain();
     }
 }
@@ -50,6 +56,7 @@ fn main() -> rltk::BError {
     gs.ecs.register::<Position>();
     gs.ecs.register::<Renderable>();
     gs.ecs.register::<Player>();
+    gs.ecs.register::<Viewshed>();
 
     let map: Map = Map::new_map_rooms_and_corridors();
     let (player_x, player_y) = map.rooms[0].center();
@@ -58,13 +65,20 @@ fn main() -> rltk::BError {
 
     gs.ecs
         .create_entity()
-        .with(Position { x: player_x, y: player_y })
+        .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,
+        })
         .build();
 
     rltk::main_loop(context, gs)

src/map.rs

@@ -1,7 +1,7 @@
-use rltk::{ RGB, Rltk, RandomNumberGenerator };
-use super::{Rect};
-use std::cmp::{min, max};
+use super::Rect;
+use rltk::{Algorithm2D, BaseMap, Point, RandomNumberGenerator, Rltk, RGB};
 use specs::prelude::*;
+use std::cmp::{max, min};
 
 #[derive(PartialEq, Copy, Clone)]
 pub enum TileType {
@@ -14,6 +14,7 @@ pub struct Map {
     pub rooms: Vec<Rect>,
     pub width: i32,
     pub height: i32,
+    pub revealed_tiles: Vec<bool>,
 }
 
 impl Map {
@@ -57,7 +58,8 @@ impl Map {
             tiles: vec![TileType::Wall; 80 * 50],
             rooms: Vec::new(),
             width: 80,
-            height: 50
+            height: 50,
+            revealed_tiles: vec![false; 80 * 50],
         };
 
         const MAX_ROOMS: i32 = 30;
@@ -105,13 +107,27 @@ impl Map {
     }
 }
 
+impl Algorithm2D for Map {
+    fn dimensions(&self) -> 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
+    }
+}
+
 pub fn draw_map(ecs: &World, ctx: &mut Rltk) {
     let map = ecs.fetch::<Map>();
 
     let mut y = 0;
     let mut x = 0;
 
-    for (_idx, tile) in map.tiles.iter().enumerate() {
+    for (idx, tile) in map.tiles.iter().enumerate() {
+        // Render a tile depending on the tile type
+        if map.revealed_tiles[idx] {
             match tile {
                 TileType::Floor => {
                     ctx.set(
@@ -132,6 +148,7 @@ pub fn draw_map(ecs: &World, ctx: &mut Rltk) {
                     );
                 }
             }
+        }
 
         // Move to the next set of coordinates
         x += 1;

src/player.rs

@@ -1,7 +1,7 @@
-use rltk::{VirtualKeyCode, Rltk};
+use super::{Map, Player, Position, State, TileType};
+use rltk::{Rltk, VirtualKeyCode};
 use specs::prelude::*;
-use super::{Position, Player, TileType, State, Map};
-use std::cmp::{min, max};
+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>();
@@ -22,21 +22,21 @@ pub fn player_input(gs: &mut State, ctx: &mut Rltk) {
     match ctx.key {
         None => {} // Nothing happened
         Some(key) => match key {
-            VirtualKeyCode::Left |
-            VirtualKeyCode::Numpad4 |
-            VirtualKeyCode::H => try_move_player(-1, 0, &mut gs.ecs),
+            VirtualKeyCode::Left | VirtualKeyCode::Numpad4 | VirtualKeyCode::H => {
+                try_move_player(-1, 0, &mut gs.ecs)
+            }
 
-            VirtualKeyCode::Right |
-            VirtualKeyCode::Numpad6 |
-            VirtualKeyCode::L=> try_move_player(1, 0, &mut gs.ecs),
+            VirtualKeyCode::Right | VirtualKeyCode::Numpad6 | VirtualKeyCode::L => {
+                try_move_player(1, 0, &mut gs.ecs)
+            }
 
-            VirtualKeyCode::Up |
-            VirtualKeyCode::Numpad8 |
-            VirtualKeyCode::K => try_move_player(0, -1, &mut gs.ecs),
+            VirtualKeyCode::Up | VirtualKeyCode::Numpad8 | VirtualKeyCode::K => {
+                try_move_player(0, -1, &mut gs.ecs)
+            }
 
-            VirtualKeyCode::Down |
-            VirtualKeyCode::Numpad2 |
-            VirtualKeyCode::J => try_move_player(0, 1, &mut gs.ecs),
+            VirtualKeyCode::Down | VirtualKeyCode::Numpad2 | VirtualKeyCode::J => {
+                try_move_player(0, 1, &mut gs.ecs)
+            }
 
             _ => {}
         },

src/visibility_system.rs

@@ -0,0 +1,36 @@
+use super::{Map, Player, Position, Viewshed};
+use rltk::{field_of_view, Point};
+use specs::prelude::*;
+
+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() {
+            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);
+
+            // if this is the player, reveal what they can see
+            let p: Option<&Player> = player.get(ent);
+            if let Some(p) = p {
+                for vis in viewshed.visible_tiles.iter() {
+                    let idx = map.xy_idx(vis.x, vis.y);
+                    map.revealed_tiles[idx] = true;
+                }
+            }
+        }
+    }
+}