Add periodically spawning powerups to FFA and CTF (#156)

Now that support for powerups has been implemented we can start adding them to the game modes. This PR adds all the normal periodically-spawning powerups for both FFA and CTF (the 3 infernos, and the base shields for FFA).

ctf/src/main.rs

@@ -1,4 +1,6 @@
-use airmash::AirmashGame;
+use std::time::Duration;
+
+use airmash::{util::PeriodicPowerupSpawner, AirmashGame, Vector2};
 use serde_deserialize_over::DeserializeOver;
 
 fn set_default_var(name: &str, value: &str) {
@@ -61,5 +63,30 @@ fn main() {
 
   airmash_server_ctf::setup_ctf_server(&mut game);
 
+  // Inferno in Europe
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(920.0, -2800.0),
+    Duration::from_secs(105),
+  ));
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(-7440.0, -1360.0),
+    Duration::from_secs(105),
+  ));
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(6565.0, -935.0),
+    Duration::from_secs(105),
+  ));
+
+  // Blue base shield
+  game.register(PeriodicPowerupSpawner::shield(
+    Vector2::new(-9300.0, -1480.0),
+    Duration::from_secs(90),
+  ));
+  // Red base shield
+  game.register(PeriodicPowerupSpawner::shield(
+    Vector2::new(8350.0, -935.0),
+    Duration::from_secs(90),
+  ));
+
   game.run_until_shutdown();
 }

ffa/src/main.rs

@@ -1,5 +1,6 @@
 use std::env;
 use std::fs::File;
+use std::time::Duration;
 
 use clap::arg;
 use serde_deserialize_over::DeserializeOver;
@@ -8,6 +9,7 @@ use server::*;
 use server::{
   protocol::GameType,
   resource::{Config, RegionName},
+  util::PeriodicPowerupSpawner,
 };
 
 mod systems;
@@ -48,6 +50,20 @@ fn main() {
   // Use the provided FFA scoreboard systems.
   server::system::ffa::register_all(&mut game);
 
+  // Inferno in Europe
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(920.0, -2800.0),
+    Duration::from_secs(105),
+  ));
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(-7440.0, -1360.0),
+    Duration::from_secs(105),
+  ));
+  game.register(PeriodicPowerupSpawner::inferno(
+    Vector2::new(6565.0, -935.0),
+    Duration::from_secs(105),
+  ));
+
   if let Some(path) = matches.value_of("config") {
     let file = match File::open(path) {
       Ok(x) => x,

server-next/src/util/mod.rs

@@ -9,8 +9,11 @@ use nalgebra::vector;
 use std::time::{Duration, Instant};
 
 pub(crate) mod escapes;
+mod powerup_spawner;
 pub mod spectate;
 
+pub use self::powerup_spawner::PeriodicPowerupSpawner;
+
 pub fn convert_time(dur: Duration) -> Time {
   dur.as_secs_f32() * 60.0
 }

server-next/src/util/powerup_spawner.rs

@@ -0,0 +1,56 @@
+use std::time::{Duration, Instant};
+
+use crate::protocol::{MobType, Position};
+use crate::{event::Frame, Entity, EventHandler};
+
+#[derive(Copy, Clone)]
+enum SpawnerState {
+  Spawned(Entity),
+  Unspawned(Instant),
+}
+
+pub struct PeriodicPowerupSpawner {
+  state: SpawnerState,
+  interval: Duration,
+  mob: MobType,
+  pos: Position,
+}
+
+impl PeriodicPowerupSpawner {
+  pub fn new(mob: MobType, pos: Position, interval: Duration) -> Self {
+    Self {
+      mob,
+      pos,
+      interval,
+      state: SpawnerState::Unspawned(Instant::now()),
+    }
+  }
+
+  pub fn inferno(pos: Position, interval: Duration) -> Self {
+    Self::new(MobType::Inferno, pos, interval)
+  }
+
+  pub fn shield(pos: Position, interval: Duration) -> Self {
+    Self::new(MobType::Shield, pos, interval)
+  }
+}
+
+impl EventHandler<Frame> for PeriodicPowerupSpawner {
+  fn on_event(&mut self, _: &Frame, game: &mut crate::AirmashGame) {
+    let frame = game.this_frame();
+
+    match self.state {
+      SpawnerState::Spawned(entity) => {
+        if !game.world.contains(entity) {
+          self.state = SpawnerState::Unspawned(frame + self.interval);
+        }
+      }
+      SpawnerState::Unspawned(next) => {
+        if frame > next {
+          let entity = game.spawn_mob(self.mob, self.pos, Duration::from_secs(60));
+          self.state = SpawnerState::Spawned(entity);
+        }
+      }
+    }
+  }
+}