Add combat example

build/entity.rs

@@ -455,7 +455,7 @@ const LIVING_ENTITY: Class = Class {
             typ: Type::OptBlockPos(None),
         },
     ],
-    events: &[],
+    events: &[Event::Hurt],
 };
 
 const MOB: Class = Class {

examples/combat.rs

@@ -0,0 +1,278 @@
+use std::net::SocketAddr;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use log::LevelFilter;
+use valence::block::{BlockPos, BlockState};
+use valence::client::Event::{self};
+use valence::client::{ClientId, GameMode, Hand, InteractWithEntityKind};
+use valence::config::{Config, ServerListPing};
+use valence::dimension::DimensionId;
+use valence::entity::state::Pose;
+use valence::entity::{EntityId, EntityKind, EntityState};
+use valence::server::{Server, SharedServer, ShutdownResult};
+use valence::text::{Color, TextFormat};
+use valence::{async_trait, Ticks};
+use vek::Vec3;
+
+pub fn main() -> ShutdownResult {
+    env_logger::Builder::new()
+        .filter_module("valence", LevelFilter::Trace)
+        .parse_default_env()
+        .init();
+
+    valence::start_server(
+        Game {
+            player_count: AtomicUsize::new(0),
+        },
+        (),
+    )
+}
+
+struct Game {
+    player_count: AtomicUsize,
+}
+
+#[derive(Default)]
+struct ClientData {
+    /// The client's player entity.
+    player: EntityId,
+    /// The extra knockback on the first hit while sprinting.
+    has_extra_knockback: bool,
+}
+
+#[derive(Default)]
+struct EntityData {
+    client: ClientId,
+    attacked: bool,
+    attacker_pos: Vec3<f64>,
+    extra_knockback: bool,
+    last_attack_time: Ticks,
+}
+
+const MAX_PLAYERS: usize = 10;
+
+const SPAWN_POS: BlockPos = BlockPos::new(0, 20, 0);
+
+#[async_trait]
+impl Config for Game {
+    type ChunkData = ();
+    type ClientData = ClientData;
+    type EntityData = EntityData;
+    type ServerData = ();
+    type WorldData = ();
+
+    fn max_connections(&self) -> usize {
+        // We want status pings to be successful even if the server is full.
+        MAX_PLAYERS + 64
+    }
+
+    fn online_mode(&self) -> bool {
+        // You'll want this to be true on real servers.
+        false
+    }
+
+    async fn server_list_ping(
+        &self,
+        _server: &SharedServer<Self>,
+        _remote_addr: SocketAddr,
+    ) -> ServerListPing {
+        ServerListPing::Respond {
+            online_players: self.player_count.load(Ordering::SeqCst) as i32,
+            max_players: MAX_PLAYERS as i32,
+            description: "Hello Valence!".color(Color::AQUA),
+            favicon_png: Some(include_bytes!("../assets/favicon.png")),
+        }
+    }
+
+    fn init(&self, server: &mut Server<Self>) {
+        let (_, world) = server.worlds.create(DimensionId::default(), ());
+        world.meta.set_flat(true);
+
+        let min_y = server.shared.dimension(DimensionId::default()).min_y;
+
+        // Create circular arena.
+        let size = 2;
+        for chunk_z in -size - 2..size + 2 {
+            for chunk_x in -size - 2..size + 2 {
+                let chunk = world.chunks.create([chunk_x, chunk_z], ());
+                let r = -size..size;
+                if r.contains(&chunk_x) && r.contains(&chunk_z) {
+                    for z in 0..16 {
+                        for x in 0..16 {
+                            let block_x = chunk_x * 16 + x as i32;
+                            let block_z = chunk_z * 16 + z as i32;
+                            if f64::hypot(block_x as f64, block_z as f64) <= size as f64 * 16.0 {
+                                for y in 0..(SPAWN_POS.y - min_y + 1) as usize {
+                                    chunk.set_block_state(x, y, z, BlockState::STONE);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        world.chunks.set_block_state(SPAWN_POS, BlockState::BEDROCK);
+    }
+
+    fn update(&self, server: &mut Server<Self>) {
+        let (world_id, world) = server.worlds.iter_mut().next().unwrap();
+
+        let current_tick = server.shared.current_tick();
+
+        server.clients.retain(|client_id, client| {
+            if client.created_tick() == current_tick {
+                if self
+                    .player_count
+                    .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |count| {
+                        (count < MAX_PLAYERS).then_some(count + 1)
+                    })
+                    .is_err()
+                {
+                    client.disconnect("The server is full!".color(Color::RED));
+                    return false;
+                }
+
+                client.spawn(world_id);
+                client.set_game_mode(GameMode::Survival);
+                client.teleport(
+                    [
+                        SPAWN_POS.x as f64 + 0.5,
+                        SPAWN_POS.y as f64 + 1.0,
+                        SPAWN_POS.z as f64 + 0.5,
+                    ],
+                    0.0,
+                    0.0,
+                );
+
+                world.meta.player_list_mut().insert(
+                    client.uuid(),
+                    client.username().to_owned(),
+                    client.textures().cloned(),
+                    client.game_mode(),
+                    0,
+                    None,
+                );
+
+                let (player_id, player) = server
+                    .entities
+                    .create_with_uuid(EntityKind::Player, client.uuid(), EntityData::default())
+                    .unwrap();
+
+                client.data.player = player_id;
+                client.data.has_extra_knockback = true;
+
+                player.data.client = client_id;
+                player.data.last_attack_time = 0;
+
+                client.send_message("Welcome to the arena.".italic());
+                if self.player_count.load(Ordering::SeqCst) <= 1 {
+                    client.send_message("Have another player join the game with you.".italic());
+                }
+            }
+
+            if client.is_disconnected() {
+                self.player_count.fetch_sub(1, Ordering::SeqCst);
+                server.entities.delete(client.data.player);
+                world.meta.player_list_mut().remove(client.uuid());
+                return false;
+            }
+
+            while let Some(event) = client.pop_event() {
+                match event {
+                    Event::StartSprinting => {
+                        client.data.has_extra_knockback = true;
+                    }
+                    Event::InteractWithEntity {
+                        id,
+                        kind: InteractWithEntityKind::Attack,
+                        ..
+                    } => {
+                        if let Some(target) = server.entities.get_mut(id) {
+                            if !target.data.attacked
+                                && current_tick - target.data.last_attack_time >= 10
+                                && id != client.data.player
+                            {
+                                target.data.attacked = true;
+                                target.data.attacker_pos = client.position();
+                                target.data.extra_knockback = client.data.has_extra_knockback;
+                                target.data.last_attack_time = current_tick;
+
+                                client.data.has_extra_knockback = false;
+                            }
+                        }
+                    }
+                    Event::ArmSwing(hand) => {
+                        let player = server.entities.get_mut(client.data.player).unwrap();
+
+                        if let EntityState::Player(e) = &mut player.state {
+                            match hand {
+                                Hand::Main => e.trigger_swing_main_arm(),
+                                Hand::Off => e.trigger_swing_offhand(),
+                            }
+                        }
+                    }
+                    _ => (),
+                }
+            }
+
+            if client.position().y <= 0.0 {
+                client.teleport(
+                    [
+                        SPAWN_POS.x as f64 + 0.5,
+                        SPAWN_POS.y as f64 + 1.0,
+                        SPAWN_POS.z as f64 + 0.5,
+                    ],
+                    client.yaw(),
+                    client.pitch(),
+                );
+            }
+
+            let player = server.entities.get_mut(client.data.player).unwrap();
+
+            player.set_world(client.world());
+            player.set_position(client.position());
+            player.set_yaw(client.yaw());
+            player.set_head_yaw(client.yaw());
+            player.set_pitch(client.pitch());
+            player.set_on_ground(client.on_ground());
+
+            if let EntityState::Player(player) = &mut player.state {
+                if client.is_sneaking() {
+                    player.set_pose(Pose::Sneaking);
+                } else {
+                    player.set_pose(Pose::Standing);
+                }
+
+                player.set_sprinting(client.is_sprinting());
+            }
+
+            true
+        });
+
+        for (_, e) in server.entities.iter_mut() {
+            if e.data.attacked {
+                e.data.attacked = false;
+                let victim = server.clients.get_mut(e.data.client).unwrap();
+
+                let mut vel = (victim.position() - e.data.attacker_pos).normalized();
+
+                let knockback_xz = if e.data.extra_knockback { 18.0 } else { 8.0 };
+                let knockback_y = if e.data.extra_knockback { 8.432 } else { 6.432 };
+
+                vel.x *= knockback_xz;
+                vel.y = knockback_y;
+                vel.z *= knockback_xz;
+
+                victim.set_velocity(victim.velocity() / 2.0 + vel.as_());
+
+                if let EntityState::Player(e) = &mut e.state {
+                    e.trigger_take_damage();
+                    e.trigger_hurt();
+                }
+                victim.player_mut().trigger_take_damage();
+                victim.player_mut().trigger_hurt();
+            }
+        }
+    }
+}

examples/conway.rs

@@ -145,14 +145,12 @@ impl Config for Game {
                     None,
                 );
 
-                let player_id = server
+                client.data.player = server
                     .entities
                     .create_with_uuid(EntityKind::Player, client.uuid(), ())
                     .unwrap()
                     .0;
 
-                client.data = ClientData { player: player_id };
-
                 client.send_message("Welcome to Conway's game of life in Minecraft!".italic());
                 client.send_message("Hold the left mouse button to bring blocks to life.".italic());
             }
@@ -164,12 +162,12 @@ impl Config for Game {
                 return false;
             }
 
-            true
-        });
-
-        for (_, client) in server.clients.iter_mut() {
             let player = server.entities.get_mut(client.data.player).unwrap();
 
+            if client.position().y <= 0.0 {
+                client.teleport(spawn_pos, client.yaw(), client.pitch());
+            }
+
             while let Some(event) = client.pop_event() {
                 match event {
                     Event::Digging { position, .. } => {
@@ -181,40 +179,6 @@ impl Config for Game {
                                 true;
                         }
                     }
-                    Event::Movement { .. } => {
-                        if client.position().y <= 0.0 {
-                            client.teleport(spawn_pos, client.yaw(), client.pitch());
-                        }
-
-                        player.set_world(client.world());
-                        player.set_position(client.position());
-                        player.set_yaw(client.yaw());
-                        player.set_head_yaw(client.yaw());
-                        player.set_pitch(client.pitch());
-                        player.set_on_ground(client.on_ground());
-                    }
-                    Event::StartSneaking => {
-                        if let EntityState::Player(e) = &mut player.state {
-                            e.set_crouching(true);
-                            e.set_pose(Pose::Sneaking);
-                        }
-                    }
-                    Event::StopSneaking => {
-                        if let EntityState::Player(e) = &mut player.state {
-                            e.set_pose(Pose::Standing);
-                            e.set_crouching(false);
-                        }
-                    }
-                    Event::StartSprinting => {
-                        if let EntityState::Player(e) = &mut player.state {
-                            e.set_sprinting(true);
-                        }
-                    }
-                    Event::StopSprinting => {
-                        if let EntityState::Player(e) = &mut player.state {
-                            e.set_sprinting(false);
-                        }
-                    }
                     Event::ArmSwing(hand) => {
                         if let EntityState::Player(e) = &mut player.state {
                             match hand {
@@ -226,8 +190,27 @@ impl Config for Game {
                     _ => {}
                 }
             }
+
+            player.set_world(client.world());
+            player.set_position(client.position());
+            player.set_yaw(client.yaw());
+            player.set_head_yaw(client.yaw());
+            player.set_pitch(client.pitch());
+            player.set_on_ground(client.on_ground());
+
+            if let EntityState::Player(player) = &mut player.state {
+                if client.is_sneaking() {
+                    player.set_pose(Pose::Sneaking);
+                } else {
+                    player.set_pose(Pose::Standing);
                 }
 
+                player.set_sprinting(client.is_sprinting());
+            }
+
+            true
+        });
+
         if server.shared.current_tick() % 4 != 0 {
             return;
         }

src/client.rs

@@ -41,7 +41,7 @@ use crate::slotmap::{Key, SlotMap};
 use crate::text::Text;
 use crate::util::{chunks_in_view_distance, is_chunk_in_view_distance};
 use crate::world::{WorldId, Worlds};
-use crate::{ident, Ticks, LIBRARY_NAMESPACE};
+use crate::{ident, Ticks, LIBRARY_NAMESPACE, STANDARD_TPS};
 
 /// A container for all [`Client`]s on a [`Server`](crate::server::Server).
 ///
@@ -175,6 +175,8 @@ pub struct Client<C: Config> {
     world: WorldId,
     new_position: Vec3<f64>,
     old_position: Vec3<f64>,
+    /// Measured in m/s.
+    velocity: Vec3<f32>,
     /// Measured in degrees
     yaw: f32,
     /// Measured in degrees
@@ -228,7 +230,8 @@ pub(crate) struct ClientFlags {
     hardcore: bool,
     attack_speed_modified: bool,
     movement_speed_modified: bool,
-    #[bits(5)]
+    velocity_modified: bool,
+    #[bits(4)]
     _pad: u8,
 }
 
@@ -252,6 +255,7 @@ impl<C: Config> Client<C> {
             world: WorldId::default(),
             new_position: Vec3::default(),
             old_position: Vec3::default(),
+            velocity: Vec3::default(),
             yaw: 0.0,
             pitch: 0.0,
             teleport_id_counter: 0,
@@ -294,6 +298,16 @@ impl<C: Config> Client<C> {
         &self.username
     }
 
+    /// Returns the sneaking state of this client.
+    pub fn is_sneaking(&self) -> bool {
+        self.flags.sneaking()
+    }
+
+    /// Returns the sprinting state of this client.
+    pub fn is_sprinting(&self) -> bool {
+        self.flags.sprinting()
+    }
+
     /// Gets the player textures of this client. If the client does not have
     /// a skin, then `None` is returned.
     pub fn textures(&self) -> Option<&SignedPlayerTextures> {
@@ -333,9 +347,9 @@ impl<C: Config> Client<C> {
     /// If you want to change the client's world, use [`Self::spawn`].
     pub fn teleport(&mut self, pos: impl Into<Vec3<f64>>, yaw: f32, pitch: f32) {
         self.new_position = pos.into();
-
         self.yaw = yaw;
         self.pitch = pitch;
+        self.velocity = Vec3::default();
 
         if !self.flags.teleported_this_tick() {
             self.flags.set_teleported_this_tick(true);
@@ -353,11 +367,18 @@ impl<C: Config> Client<C> {
         }
     }
 
+    /// Gets the velocity of this client in m/s.
+    ///
+    /// The velocity of a client is derived from their current and previous
+    /// position.
+    pub fn velocity(&self) -> Vec3<f32> {
+        self.velocity
+    }
+
+    /// Sets the client's velocity in m/s.
     pub fn set_velocity(&mut self, velocity: impl Into<Vec3<f32>>) {
-        self.send_packet(SetEntityMotion {
-            entity_id: VarInt(0),
-            velocity: velocity_to_packet_units(velocity.into()),
-        });
+        self.velocity = velocity.into();
+        self.flags.set_velocity_modified(true);
     }
 
     /// Gets this client's yaw.
@@ -610,14 +631,25 @@ impl<C: Config> Client<C> {
             if client.pending_teleports == 0 {
                 // TODO: validate movement using swept AABB collision with the blocks.
                 // TODO: validate that the client is actually inside/outside the vehicle?
+
+                // Movement packets should be coming in at a rate of STANDARD_TPS.
+                let new_velocity = (new_position - client.new_position).as_() * STANDARD_TPS as f32;
+
                 let event = Event::Movement {
-                    position: client.new_position,
-                    yaw: client.yaw,
-                    pitch: client.pitch,
-                    on_ground: client.flags.on_ground(),
+                    old_position: client.new_position,
+                    old_velocity: client.velocity,
+                    old_yaw: client.yaw,
+                    old_pitch: client.pitch,
+                    old_on_ground: client.flags.on_ground(),
+                    new_position,
+                    new_velocity,
+                    new_yaw,
+                    new_pitch,
+                    new_on_ground,
                 };
 
                 client.new_position = new_position;
+                client.velocity = new_velocity;
                 client.yaw = new_yaw;
                 client.pitch = new_pitch;
                 client.flags.set_on_ground(new_on_ground);
@@ -787,21 +819,34 @@ impl<C: Config> Client<C> {
                 // - Can't jump with a horse if not on a horse
                 // - Can't open horse inventory if not on a horse.
                 // - Can't fly with elytra if not wearing an elytra.
+                // - Can't jump with horse while already jumping & vice versa?
                 self.events.push_back(match e.action_id {
                     PlayerCommandId::StartSneaking => {
+                        if self.flags.sneaking() {
+                            return;
+                        }
                         self.flags.set_sneaking(true);
                         Event::StartSneaking
                     }
                     PlayerCommandId::StopSneaking => {
+                        if !self.flags.sneaking() {
+                            return;
+                        }
                         self.flags.set_sneaking(false);
                         Event::StopSneaking
                     }
                     PlayerCommandId::LeaveBed => Event::LeaveBed,
                     PlayerCommandId::StartSprinting => {
+                        if self.flags.sprinting() {
+                            return;
+                        }
                         self.flags.set_sprinting(true);
                         Event::StartSprinting
                     }
                     PlayerCommandId::StopSprinting => {
+                        if !self.flags.sprinting() {
+                            return;
+                        }
                         self.flags.set_sprinting(false);
                         Event::StopSprinting
                     }
@@ -914,6 +959,7 @@ impl<C: Config> Client<C> {
             self.teleport(self.position(), self.yaw(), self.pitch());
         } else {
             if self.flags.spawn() {
+                self.flags.set_spawn(false);
                 self.loaded_entities.clear();
                 self.loaded_chunks.clear();
 
@@ -1117,6 +1163,17 @@ impl<C: Config> Client<C> {
             });
         }
 
+        // Set velocity. Do this after teleporting since teleporting sets velocity to
+        // zero.
+        if self.flags.velocity_modified() {
+            self.flags.set_velocity_modified(false);
+
+            self.send_packet(SetEntityMotion {
+                entity_id: VarInt(0),
+                velocity: velocity_to_packet_units(self.velocity),
+            });
+        }
+
         // Send chat messages.
         for msg in self.msgs_to_send.drain(..) {
             send_packet(
@@ -1244,7 +1301,6 @@ impl<C: Config> Client<C> {
                 metadata: RawBytes(data),
             });
         }
-        self.player_data.clear_modifications();
 
         // Spawn new entities within the view distance.
         let pos = self.position();
@@ -1253,7 +1309,7 @@ impl<C: Config> Client<C> {
             |id, _| {
                 let entity = entities
                     .get(id)
-                    .expect("entities in spatial index should be valid");
+                    .expect("entity IDs in spatial index should be valid at this point");
                 if entity.kind() != EntityKind::Marker
                     && entity.uuid() != self.uuid
                     && self.loaded_entities.insert(id)
@@ -1288,8 +1344,8 @@ impl<C: Config> Client<C> {
             // any effect.
         }
 
+        self.player_data.clear_modifications();
         self.old_position = self.new_position;
-        self.flags.set_spawn(false);
     }
 }
 

src/client/event.rs

@@ -24,17 +24,28 @@ pub enum Event {
     /// Settings were changed. The value in this variant is the _previous_
     /// client settings.
     SettingsChanged(Option<Settings>),
-    /// The client moved. The values in this
-    /// variant are the _previous_ position and look.
+    /// The client moved.
     Movement {
         /// Absolute coordinates of the previous position.
-        position: Vec3<f64>,
+        old_position: Vec3<f64>,
+        /// Previous velocity in m/s.
+        old_velocity: Vec3<f32>,
         /// The previous yaw (in degrees).
-        yaw: f32,
+        old_yaw: f32,
         /// The previous pitch (in degrees).
-        pitch: f32,
+        old_pitch: f32,
         /// If the client was previously on the ground.
-        on_ground: bool,
+        old_on_ground: bool,
+        /// Absolute coodinates of the new position.
+        new_position: Vec3<f64>,
+        /// New velocity in m/s.
+        new_velocity: Vec3<f32>,
+        /// The new yaw (in degrees).
+        new_yaw: f32,
+        /// The new pitch (in degrees).
+        new_pitch: f32,
+        /// If the client is now on the ground.
+        new_on_ground: bool,
     },
     StartSneaking,
     StopSneaking,

src/config.rs

@@ -10,7 +10,7 @@ use crate::biome::Biome;
 use crate::dimension::Dimension;
 use crate::server::{NewClientData, Server, SharedServer};
 use crate::text::Text;
-use crate::Ticks;
+use crate::{Ticks, STANDARD_TPS};
 
 /// A trait for the configuration of a server.
 ///
@@ -65,9 +65,9 @@ pub trait Config: 'static + Sized + Send + Sync + UnwindSafe + RefUnwindSafe {
     ///
     /// # Default Implementation
     ///
-    /// Returns `20`, which is the same as Minecraft's official server.
+    /// Returns [`STANDARD_TPS`].
     fn tick_rate(&self) -> Ticks {
-        20
+        STANDARD_TPS
     }
 
     /// Called once at startup to get the "online mode" option, which determines

src/entity.rs

@@ -22,6 +22,7 @@ use crate::protocol_inner::{ByteAngle, RawBytes, VarInt};
 use crate::slotmap::{Key, SlotMap};
 use crate::util::aabb_from_bottom_and_size;
 use crate::world::WorldId;
+use crate::STANDARD_TPS;
 
 /// A container for all [`Entity`]s on a [`Server`](crate::server::Server).
 ///
@@ -583,7 +584,7 @@ impl<C: Config> Entity<C> {
 
 pub(crate) fn velocity_to_packet_units(vel: Vec3<f32>) -> Vec3<i16> {
     // The saturating cast to i16 is desirable.
-    (vel * 400.0).as_()
+    (8000.0 / STANDARD_TPS as f32 * vel).as_()
 }
 
 pub(crate) enum EntitySpawnPacket {

src/lib.rs

@@ -168,11 +168,15 @@ pub const VERSION_NAME: &str = "1.19";
 /// [identifiers](crate::ident::Ident).
 ///
 /// You should avoid using this namespace in your own identifiers.
-const LIBRARY_NAMESPACE: &str = "valence";
+pub const LIBRARY_NAMESPACE: &str = "valence";
 
 /// A discrete unit of time where 1 tick is the duration of a
 /// single game update.
 ///
-/// The duration of a game update depends on the current configuration, which
-/// may or may not be the same as Minecraft's standard 20 ticks/second.
+/// The duration of a game update on a Valence server depends on the current
+/// configuration. In some contexts, "ticks" refer to the configured tick rate
+/// while others refer to Minecraft's [standard TPS](STANDARD_TPS).
 pub type Ticks = i64;
+
+/// Minecraft's standard ticks per second (TPS).
+pub const STANDARD_TPS: Ticks = 20;