Status bar

src/main.rs

@@ -93,6 +93,41 @@ impl Object {
     let dy = other.y - self.y;
     ((dx.pow(2) + dy.pow(2)) as f32).sqrt()
   }
+
+  pub fn take_damage(&mut self, damage: i32) {
+    // Apply damage if possible
+    if let Some(fighter) = self.fighter.as_mut() {
+      if damage > 0 {
+        fighter.hp -= damage;
+      }
+    }
+
+    // Check for death, call the death function
+    if let Some(fighter) = self.fighter {
+      if fighter.hp <= 0 {
+        self.alive = false;
+        fighter.on_death.callback(self);
+      }
+    }
+  }
+
+  pub fn attack(&mut self, target: &mut Object) {
+    // A simple formula for attack damage
+    let damage = self.fighter.map_or(0, |f| f.power) - target.fighter.map_or(0, |f| f.defense);
+    if damage > 0 {
+      // Make the target take some damage
+      println!(
+        "{} attacks {} for {} hit points.",
+        self.name, target.name, damage
+      );
+      target.take_damage(damage);
+    } else {
+      println!(
+        "{} attacks {} but it has no effect!",
+        self.name, target.name
+      )
+    }
+  }
 }
 
 #[derive(Clone, Copy, Debug)]
@@ -163,6 +198,7 @@ struct Fighter {
   hp: i32,
   defense: i32,
   power: i32,
+  on_death: DeathCallback,
 }
 
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -177,6 +213,23 @@ enum Ai {
   Basic,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq)]
+enum DeathCallback {
+  Player,
+  Monster,
+}
+
+impl DeathCallback {
+  fn callback(self, object: &mut Object) {
+    use DeathCallback::*;
+    let callback: fn(&mut Object) = match self {
+      Player => player_death,
+      Monster => monster_death,
+    };
+    callback(object);
+  }
+}
+
 fn handle_keys(tcod: &mut Tcod, game: &Game, objects: &mut Vec<Object>) -> PlayerAction {
   use tcod::input::Key;
   use tcod::input::KeyCode::*;
@@ -305,6 +358,7 @@ fn place_objects(room: Rect, map: &Map, objects: &mut Vec<Object>) {
           hp: 10,
           defense: 0,
           power: 3,
+          on_death: DeathCallback::Monster,
         });
         orc.ai = Some(Ai::Basic);
         orc
@@ -316,6 +370,7 @@ fn place_objects(room: Rect, map: &Map, objects: &mut Vec<Object>) {
           hp: 16,
           defense: 1,
           power: 4,
+          on_death: DeathCallback::Monster,
         });
         troll.ai = Some(Ai::Basic);
         troll
@@ -351,15 +406,15 @@ fn player_move_or_attack(dx: i32, dy: i32, game: &Game, objects: &mut [Object])
   let y = objects[PLAYER].y + dy;
 
   // Try to find an attackable object there
-  let target_id = objects.iter().position(|object| object.pos() == (x, y));
+  let target_id = objects
+    .iter()
+    .position(|object| object.fighter.is_some() && object.pos() == (x, y));
 
   // Attack target if found, move otherwise
   match target_id {
     Some(target_id) => {
-      println!(
-        "The {} laughs at your puny efforts to attack him!",
-        objects[target_id].name
-      );
+      let (player, target) = mut_two(PLAYER, target_id, objects);
+      player.attack(target);
     }
     None => {
       move_by(PLAYER, dx, dy, &game.map, objects);
@@ -390,15 +445,44 @@ fn ai_take_turn(monster_id: usize, tcod: &Tcod, game: &Game, objects: &mut [Obje
       move_towards(monster_id, player_x, player_y, &game.map, objects);
     } else if objects[PLAYER].fighter.map_or(false, |f| f.hp > 0) {
       // Close enough, attach! (if the player is still alive.)
-      let monster = &objects[monster_id];
-      println!(
-        "The attack of the {} bounces off your shiny metal armor!",
-        monster.name
-      );
+      let (monster, player) = mut_two(monster_id, PLAYER, objects);
+      monster.attack(player);
     }
   }
 }
 
+fn mut_two<T>(first_index: usize, second_index: usize, items: &mut [T]) -> (&mut T, &mut T) {
+  assert!(first_index != second_index);
+  let split_at_index = cmp::max(first_index, second_index);
+  let (first_slice, second_slice) = items.split_at_mut(split_at_index);
+  if first_index < second_index {
+    (&mut first_slice[first_index], &mut second_slice[0])
+  } else {
+    (&mut second_slice[0], &mut first_slice[second_index])
+  }
+}
+
+fn player_death(player: &mut Object) {
+  // The game ended!
+  println!("You died!");
+
+  // For added effect, transform the player into corpse!
+  player.char = '%';
+  player.color = DARK_RED;
+}
+
+fn monster_death(monster: &mut Object) {
+  // Transform it into a nasty corpse! It doesn't block, can't be
+  // attacked and doesn't move
+  println!("{} is dead!", monster.name);
+  monster.char = '%';
+  monster.color = DARK_RED;
+  monster.blocks = false;
+  monster.fighter = None;
+  monster.ai = None;
+  monster.name = format!("remains of {}", monster.name);
+}
+
 fn render_all(tcod: &mut Tcod, game: &mut Game, objects: &[Object], fov_recompute: bool) {
   if fov_recompute {
     let player = &objects[PLAYER];
@@ -407,11 +491,18 @@ fn render_all(tcod: &mut Tcod, game: &mut Game, objects: &[Object], fov_recomput
       .compute_fov(player.x, player.y, TORCH_RADIUS, FOV_LIGHT_WALLS, FOV_ALGO);
   }
 
-  // Draw all objects in the list
-  for object in objects {
-    if tcod.fov.is_in_fov(object.x, object.y) {
-      object.draw(&mut tcod.con);
-    }
+  // Only render objects in fov
+  let mut to_draw: Vec<_> = objects
+    .iter()
+    .filter(|o| tcod.fov.is_in_fov(o.x, o.y))
+    .collect();
+
+  // Sort so that non-blocking objects are rendered behind blocking objects
+  to_draw.sort_by(|o1, o2| o1.blocks.cmp(&o2.blocks));
+
+  // Draw objects in the list
+  for object in &to_draw {
+    object.draw(&mut tcod.con);
   }
 
   // Go through all tiles and set their background color
@@ -439,6 +530,18 @@ fn render_all(tcod: &mut Tcod, game: &mut Game, objects: &[Object], fov_recomput
     }
   }
 
+  // Show the player's stats
+  tcod.root.set_default_foreground(WHITE);
+  if let Some(fighter) = objects[PLAYER].fighter {
+    tcod.root.print_ex(
+      1,
+      SCREEN_HEIGHT - 2,
+      BackgroundFlag::None,
+      TextAlignment::Left,
+      format!("HP: {}/{} ", fighter.hp, fighter.max_hp),
+    );
+  }
+
   // Blit contents of "con" to the root console
   blit(
     &tcod.con,
@@ -475,6 +578,7 @@ fn main() {
     hp: 30,
     defense: 2,
     power: 5,
+    on_death: DeathCallback::Player,
   });
 
   // List of objects in the world