From 6705af361125041c2227fce0be6331d26c633269 Mon Sep 17 00:00:00 2001
From: Peter Hart <cinphart@gmail.com>
Date: Sun, 15 Mar 2020 16:25:37 -0400
Subject: [PATCH] movement and simple map drawing

---
 src/main.rs | 143 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 135 insertions(+), 8 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index bc21f88..3ad4c8f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,9 +22,130 @@ struct State {
     ecs: World
 }
 
+#[derive(Component)]
+struct LeftMover {}
+
+
+#[derive(PartialEq, Copy, Clone)]
+enum TileType {
+    Wall, Floor
+}
+
+pub fn xy_idx(x: i32, y: i32) -> usize {
+    (y as usize * 80) + x as usize
+}
+
+fn new_map() -> Vec<TileType> {
+    let mut map = vec![TileType::Floor; 80*50];
+
+    // Make the boundaries 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 we'll randomly splat a bunch of walls. It won't be pretty, but it's a decent illustration.
+    // First, obtain the thread-local RNG:
+    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() {
+        // Render a tile depending upon the tile type
+        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 the coordinates
+        x += 1;
+        if x > 79 {
+            x = 0;
+            y += 1;
+        }
+    }
+}
+
+
+#[derive(Component, Debug)]
+struct Player {}
+
+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>();
+
+    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));
+    }
+}
+
+fn player_input(gs: &mut State, ctx: &mut Rltk) {
+    // Player movement
+    match ctx.key {
+        None => {} // Nothing happened
+        Some(key) => match key {
+            VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs),
+            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),
+            _ => {}
+        },
+    }
+}
+
+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) {
+        let mut lw = LeftWalker{};
+        lw.run_now(&self.ecs);
+        self.ecs.maintain();
+    }
+}
+
 impl GameState for State {
     fn tick(&mut self, ctx : &mut Rltk) {
         ctx.cls();
+	self.run_systems();
+	player_input(self, ctx);
+	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>();
 
@@ -44,6 +165,8 @@ fn main() {
     };
     gs.ecs.register::<Position>();
     gs.ecs.register::<Renderable>();
+    gs.ecs.register::<LeftMover>();
+    gs.ecs.register::<Player>();
 
     gs.ecs
         .create_entity()
@@ -53,20 +176,24 @@ fn main() {
             fg: RGB::named(rltk::YELLOW),
             bg: RGB::named(rltk::BLACK),
         })
+	.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),
-        })
-        .build();
+            .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();
     }
 
+    gs.ecs.insert(new_map());
+    
     rltk::main_loop(context, gs);
 }