place simple monsters, add dirty flag for viewshed

src/main.rs

@@ -17,17 +17,19 @@ pub struct State {
     ecs: World,
 }
 
-fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
+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 mut viewsheds = ecs.write_storage::<Viewshed>();
     let map = ecs.fetch::<Map>();
 
-    for (_player, pos) in (&mut players, &mut positions).join() {
-        let x = min(79, max(0, pos.x + delta_x));
-        let y = min(49, max(0, pos.y + delta_y));
-        if map.tile_at(x, y) != TileType::Wall {
-            pos.x = x;
-            pos.y = y;
+    for (_player, pos, viewshed) in (&mut players, &mut positions, &mut viewsheds).join() {
+        let destination_idx = map.xy_idx(pos.x + delta_x, pos.y + delta_y);
+        if map.tiles[destination_idx] != TileType::Wall {
+            pos.x = min(79 , max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
+
+            viewshed.dirty = true;
         }
     }
 }
@@ -141,9 +143,28 @@ fn main() {
         .with(Viewshed {
             visible_tiles: Vec::new(),
             range: 8,
+            dirty: true,
         })
         .build();
 
+    for room in map.rooms.iter().skip(1) {
+        let (x, y) = room.center();
+        gs.ecs
+            .create_entity()
+            .with(Position { x, y })
+            .with(Renderable {
+                glyph: rltk::to_cp437('g'),
+                fg: RGB::named(rltk::RED),
+                bg: RGB::named(rltk::BLACK),
+            })
+            .with(Viewshed {
+                visible_tiles: Vec::new(),
+                range: 8,
+                dirty: true,
+            })
+            .build();
+    }
+
     gs.ecs.insert(map);
 
     rltk::main_loop(context, gs);