Add first entity

src/main.rs

@@ -1,6 +1,24 @@
-use rltk::{Rltk, GameState};
+use rltk::{GameState, Rltk, VirtualKeyCode, RGB};
+use specs::prelude::*;
+use specs_derive::Component;
+use std::cmp::{max, min};
 
-struct State {}
+#[derive(Component)]
+struct Position {
+    x: i32,
+    y: i32,
+}
+
+#[derive(Component)]
+struct Renderable {
+    glyph: rltk::FontCharType,
+    fg: RGB,
+    bg: RGB,
+}
+
+struct State {
+    ecs: World,
+}
 
 impl GameState for State {
     fn tick(&mut self, ctx: &mut Rltk) {
@@ -16,7 +34,20 @@ fn main() -> rltk::BError {
         .with_title("Roguelike Tutorial")
         .build()?;
 
-    let gs = State {};
+    let mut gs = State { ecs: World::new() };
+
+    gs.ecs.register::<Position>();
+    gs.ecs.register::<Renderable>();
+
+    gs.ecs
+        .create_entity()
+        .with(Position { x: 40, y: 25 })
+        .with(Renderable {
+            glyph: rltk::to_cp437('@'),
+            fg: RGB::named(rltk::YELLOW),
+            bg: RGB::named(rltk::BLACK),
+        })
+        .build();
 
     rltk::main_loop(context, gs)
 }