From 7923d488ef6cf62f5757cb4ecfaf89e1cbb9441c Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Thu, 21 Oct 2021 14:52:03 -0400
Subject: [PATCH] Complete chapter 2.2

---
 src/main.rs | 127 ++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 88 insertions(+), 39 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 0b49d56..90aae53 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,9 +16,6 @@ struct Renderable {
     bg: RGB,
 }
 
-#[derive(Component)]
-struct LeftMover {}
-
 #[derive(Component, Debug)]
 struct Player {}
 
@@ -26,13 +23,23 @@ struct State {
     ecs: World,
 }
 
+#[derive(PartialEq, Copy, Clone)]
+enum TileType {
+    Wall,
+    Floor,
+}
+
 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>>();
 
     for (_player, pos) in (&mut players, &mut positions).join() {
-        pos.x = min(79, max(0, pos.x + delta_x));
-        pos.y = min(49, max(0, pos.y + delta_y));
+        let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
+        if map[destination_idx] != TileType::Wall {
+            pos.x = min(79, max(0, pos.x + delta_x));
+            pos.y = min(49, max(0, pos.y + delta_y));
+        }
     }
 }
 
@@ -45,11 +52,76 @@ fn player_input(gs: &mut State, ctx: &mut Rltk) {
             VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs),
             VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs),
             VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs),
-            _ => {},
+            _ => {}
         },
     }
 }
 
+fn new_map() -> Vec<TileType> {
+    let mut map = vec![TileType::Floor; 80 * 50];
+
+    // Make the boundary walls
+    for x in 0..80 {
+        map[xy_idx(x, 0)] = TileType::Wall;
+        map[xy_idx(x, 49)] = TileType::Wall;
+    }
+    for y in 0..50 {
+        map[xy_idx(0, y)] = TileType::Wall;
+        map[xy_idx(79, y)] = TileType::Wall;
+    }
+
+    // Now randomly add a bunch of walls.
+    // First get the random number generator
+    let mut rng = rltk::RandomNumberGenerator::new();
+
+    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;
+        }
+    }
+
+    map
+}
+
+fn draw_map(map: &[TileType], ctx: &mut Rltk) {
+    let mut y = 0;
+    let mut x = 0;
+
+    for tile in map.iter() {
+        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('.'),
+                );
+            }
+            TileType::Wall => {
+                ctx.set(
+                    x,
+                    y,
+                    RGB::from_f32(0.0, 1.0, 0.0),
+                    RGB::from_f32(0., 0., 0.),
+                    rltk::to_cp437('#'),
+                );
+            }
+        }
+
+        // Move to the next set of coordinates
+        x += 1;
+        if x > 79 {
+            x = 0;
+            y += 1;
+        }
+    }
+}
+
 impl GameState for State {
     fn tick(&mut self, ctx: &mut Rltk) {
         ctx.cls();
@@ -57,6 +129,9 @@ impl GameState for State {
         player_input(self, ctx);
         self.run_systems();
 
+        let map = self.ecs.fetch::<Vec<TileType>>();
+        draw_map(&map, ctx);
+
         let positions = self.ecs.read_storage::<Position>();
         let renderables = self.ecs.read_storage::<Renderable>();
 
@@ -66,28 +141,14 @@ impl GameState for State {
     }
 }
 
-struct LeftWalker {}
-
-impl<'a> System<'a> for LeftWalker {
-    type SystemData = (ReadStorage<'a, LeftMover>, WriteStorage<'a, Position>);
-
-    fn run(&mut self, (lefty, mut pos): Self::SystemData) {
-        for (_lefty, pos) in (&lefty, &mut pos).join() {
-            pos.x -= 1;
-
-            if pos.x < 0 {
-                pos.x = 79;
-            }
-        }
+impl State {
+    fn run_systems(&mut self) {
+        self.ecs.maintain();
     }
 }
 
-impl State {
-    fn run_systems(&mut self) {
-        let mut lw = LeftWalker{};
-        lw.run_now(&self.ecs);
-        self.ecs.maintain();
-    }
+pub fn xy_idx(x: i32, y: i32) -> usize {
+    (y as usize * 80) + x as usize
 }
 
 fn main() -> rltk::BError {
@@ -101,9 +162,10 @@ fn main() -> rltk::BError {
 
     gs.ecs.register::<Position>();
     gs.ecs.register::<Renderable>();
-    gs.ecs.register::<LeftMover>();
     gs.ecs.register::<Player>();
 
+    gs.ecs.insert(new_map());
+
     gs.ecs
         .create_entity()
         .with(Position { x: 40, y: 25 })
@@ -115,18 +177,5 @@ fn main() -> rltk::BError {
         .with(Player {})
         .build();
 
-    for i in 0..10 {
-        gs.ecs
-            .create_entity()
-            .with(Position { x: i * 7, y: 20 })
-            .with(Renderable {
-                glyph: rltk::to_cp437('☺'),
-                fg: RGB::named(rltk::RED),
-                bg: RGB::named(rltk::BLACK),
-            })
-            .with(LeftMover {})
-            .build();
-    }
-
     rltk::main_loop(context, gs)
 }