feat: vanish 💨 (#670)

added `/vanish` command for admins.

---------

Co-authored-by: Andrew Gazelka <andrew.gazelka@gmail.com>

Author: Tebarem

Cargo.lock

@@ -258,17 +258,6 @@ pub fn player_join_world(
 
                     metadata.encode(*flags);
 
-                    if let Some(view) = metadata.get_and_clear() {
-                        let pkt = play::EntityTrackerUpdateS2c {
-                            entity_id: VarInt(query_entity.minecraft_id()),
-                            tracked_values: RawBytes(&view),
-                        };
-
-                        bundle
-                            .add_packet(&pkt)
-                            .context("failed to send player spawn packet")?;
-                    }
-
                     Ok(())
                 };
 

crates/hyperion/src/egress/player_join/mod.rs

@@ -6,12 +6,19 @@ use glam::Vec3;
 use hyperion_inventory::PlayerInventory;
 use hyperion_utils::EntityExt;
 use tracing::error;
-use valence_protocol::{RawBytes, VarInt, packets::play};
+use valence_protocol::{
+    RawBytes, VarInt,
+    packets::play::{self},
+};
 
 use crate::{
     Prev,
     net::{Compose, ConnectionId},
-    simulation::{Position, Velocity, Xp, animation::ActiveAnimation, metadata::MetadataChanges},
+    simulation::{
+        Position, Velocity, Xp,
+        animation::ActiveAnimation,
+        metadata::{MetadataChanges, get_and_clear_metadata},
+    },
 };
 
 #[derive(Component)]
@@ -115,7 +122,7 @@ impl Module for EntityStateSyncModule {
                 let entity = it.entity(row);
                 let entity_id = VarInt(entity.minecraft_id());
 
-                let metadata = metadata_changes.get_and_clear();
+                let metadata = get_and_clear_metadata(metadata_changes);
 
                 if let Some(view) = metadata {
                     let pkt = play::EntityTrackerUpdateS2c {

crates/hyperion/src/egress/sync_entity_state.rs

@@ -233,16 +233,6 @@ impl MetadataChanges {
         let r#type = metadata.to_type();
         r#type.encode(&mut self.0).unwrap();
     }
-
-    pub fn get_and_clear(&mut self) -> Option<MetadataView<'_>> {
-        if self.is_empty() {
-            return None;
-        }
-        // denote end of metadata
-        self.0.push(0xff);
-
-        Some(MetadataView(self))
-    }
 }
 
 #[derive(Debug)]
@@ -261,3 +251,14 @@ impl Drop for MetadataView<'_> {
         self.0.0.clear();
     }
 }
+
+/// This is only meant to be called from egress systems
+pub(crate) fn get_and_clear_metadata(metadata: &mut MetadataChanges) -> Option<MetadataView<'_>> {
+    if metadata.is_empty() {
+        return None;
+    }
+    // denote end of metadata
+    metadata.0.push(0xff);
+
+    Some(MetadataView(metadata))
+}

crates/hyperion/src/simulation/metadata/mod.rs

@@ -25,7 +25,8 @@ tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 tracing-tracy = { workspace = true }
 uuid = { version = "1.11.0", features = ["v4"] }
-
+valence_protocol = { workspace = true }
+valence_server = { workspace = true }
 
 [dev-dependencies]
 tracing = {workspace = true, features = ["release_max_level_info"]}

events/tag/Cargo.toml

@@ -4,7 +4,7 @@ use hyperion_clap::{MinecraftCommand, hyperion_command::CommandRegistry};
 use crate::command::{
     bow::BowCommand, class::ClassCommand, fly::FlyCommand, gui::GuiCommand,
     raycast::RaycastCommand, replace::ReplaceCommand, shoot::ShootCommand, spawn::SpawnCommand,
-    speed::SpeedCommand, xp::XpCommand,
+    speed::SpeedCommand, vanish::VanishCommand, xp::XpCommand,
 };
 
 mod bow;
@@ -16,17 +16,19 @@ mod replace;
 mod shoot;
 mod spawn;
 mod speed;
+mod vanish;
 mod xp;
 
 pub fn register(registry: &mut CommandRegistry, world: &World) {
     BowCommand::register(registry, world);
     ClassCommand::register(registry, world);
     FlyCommand::register(registry, world);
+    GuiCommand::register(registry, world);
     RaycastCommand::register(registry, world);
     ReplaceCommand::register(registry, world);
     ShootCommand::register(registry, world);
+    SpawnCommand::register(registry, world);
     SpeedCommand::register(registry, world);
+    VanishCommand::register(registry, world);
     XpCommand::register(registry, world);
-    SpawnCommand::register(registry, world);
-    GuiCommand::register(registry, world);
 }

events/tag/src/command.rs

@@ -0,0 +1,44 @@
+use clap::Parser;
+use flecs_ecs::{
+    core::{Entity, EntityView, EntityViewGet, WorldProvider},
+    prelude::*,
+};
+use hyperion::net::{Compose, ConnectionId};
+use hyperion_clap::{CommandPermission, MinecraftCommand};
+
+use crate::module::vanish::Vanished;
+
+#[derive(Parser, CommandPermission, Debug)]
+#[command(name = "vanish")]
+#[command_permission(group = "Admin")]
+pub struct VanishCommand;
+
+impl MinecraftCommand for VanishCommand {
+    fn execute(self, system: EntityView<'_>, caller: Entity) {
+        let world = system.world();
+
+        world.get::<&Compose>(|compose| {
+            caller.entity_view(world).get::<(
+                Option<&Vanished>,
+                &ConnectionId,
+                &hyperion::simulation::Name,
+            )>(|(vanished, stream, name)| {
+                let is_vanished = vanished.is_some_and(Vanished::is_vanished);
+                let caller = caller.entity_view(world);
+                if is_vanished {
+                    caller.set(Vanished::new(false));
+                    let packet = hyperion::net::agnostic::chat(format!(
+                        "§7[Admin] §f{name} §7is now visible",
+                    ));
+                    compose.unicast(&packet, *stream, system).unwrap();
+                } else {
+                    caller.set(Vanished::new(true));
+                    let packet = hyperion::net::agnostic::chat(format!(
+                        "§7[Admin] §f{name} §7is now vanished",
+                    ));
+                    compose.unicast(&packet, *stream, system).unwrap();
+                }
+            });
+        });
+    }
+}

events/tag/src/command/vanish.rs

@@ -12,7 +12,7 @@ use hyperion::{
     simulation::{Player, blocks::Blocks},
 };
 use hyperion_clap::hyperion_command::CommandRegistry;
-use module::block::BlockModule;
+use module::{block::BlockModule, vanish::VanishModule};
 
 mod module;
 
@@ -97,6 +97,7 @@ impl Module for TagModule {
         world.import::<hyperion_utils::HyperionUtilsModule>();
         world.import::<hyperion_clap::ClapCommandModule>();
         world.import::<SkinModule>();
+        world.import::<VanishModule>();
 
         world.get::<&mut CommandRegistry>(|registry| {
             command::register(registry, world);

events/tag/src/lib.rs

@@ -6,3 +6,4 @@ pub mod level;
 pub mod regeneration;
 pub mod spawn;
 pub mod stats;
+pub mod vanish;

events/tag/src/module.rs

@@ -0,0 +1,87 @@
+use flecs_ecs::{core::World, prelude::*};
+use hyperion::{
+    net::{Compose, ConnectionId},
+    simulation::{Uuid, metadata::entity::EntityFlags},
+};
+use valence_protocol::packets::play::{self, player_list_s2c::PlayerListActions};
+use valence_server::GameMode;
+
+#[derive(Component)]
+pub struct VanishModule;
+
+#[derive(Default, Component, Debug)]
+pub struct Vanished(pub bool);
+
+impl Vanished {
+    #[must_use]
+    pub const fn new(is_vanished: bool) -> Self {
+        Self(is_vanished)
+    }
+
+    #[must_use]
+    pub const fn is_vanished(&self) -> bool {
+        self.0
+    }
+}
+
+impl Module for VanishModule {
+    fn module(world: &World) {
+        world.component::<Vanished>();
+
+        system!(
+            "vanish_sync",
+            world,
+            &Compose($),
+            &ConnectionId,
+            &Vanished,
+            &Uuid,
+        )
+        .multi_threaded()
+        .kind::<flecs::pipeline::PreStore>()
+        .each_iter(move |it, row, (compose, _connection_id, vanished, uuid)| {
+            let entity = it.entity(row);
+            let system = it.system();
+            let world = it.world();
+
+            if vanished.is_vanished() {
+                // Remove from player list and make them invisible
+                let remove_packet = play::PlayerListS2c {
+                    actions: PlayerListActions::new()
+                        .with_update_listed(true)
+                        .with_update_game_mode(true),
+                    entries: vec![play::player_list_s2c::PlayerListEntry {
+                        player_uuid: uuid.0,
+                        listed: false,
+                        game_mode: GameMode::Survival,
+                        ..Default::default()
+                    }]
+                    .into(),
+                };
+                compose.broadcast(&remove_packet, system).send().unwrap();
+
+                // Set entity flags to make them invisible
+                let flags = EntityFlags::INVISIBLE;
+                entity.entity_view(world).set(flags);
+            } else {
+                // Add back to player list and make them visible
+                let add_packet = play::PlayerListS2c {
+                    actions: PlayerListActions::new()
+                        .with_update_listed(true)
+                        .with_update_game_mode(true),
+                    entries: vec![play::player_list_s2c::PlayerListEntry {
+                        player_uuid: uuid.0,
+                        listed: true,
+                        game_mode: GameMode::Survival,
+                        ..Default::default()
+                    }]
+                    .into(),
+                };
+                compose.broadcast(&add_packet, system).send().unwrap();
+
+                // Clear invisible flag
+                let flags = EntityFlags::default();
+                entity.entity_view(world).set(flags);
+            }
+        });
+    }
+}