feather-rs · caelunshun · Mar 5, 2021 · Mar 2, 2021 · Mar 3, 2021 · Mar 3, 2021
diff --git a/feather/common/src/entities/player.rs b/feather/common/src/entities/player.rs
@@ -1,8 +1,36 @@
+use anyhow::bail;
 use base::EntityKind;
-use ecs::EntityBuilder;
+use ecs::{EntityBuilder, SysResult};
 use quill_common::entities::Player;
 
 pub fn build_default(builder: &mut EntityBuilder) {
     super::build_default(builder);
     builder.add(Player).add(EntityKind::Player);
 }
+
+/// The hotbar slot a player's cursor is currently on
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub struct HotbarSlot(usize);
+
+impl HotbarSlot {
+    pub fn new(id: usize) -> Self {
+        Self(id)
+    }
+
+    pub fn default() -> Self {
+        Self(0)
+    }
+
+    pub fn get(&self) -> usize {
+        self.0
+    }
+
+    pub fn set(&mut self, id: usize) -> SysResult {
+        if id > 8 {
+            bail!("invalid hotbar slot id");
+        }
+
+        self.0 = id;
+        Ok(())
+    }
+}
diff --git a/feather/server/src/packet_handlers.rs b/feather/server/src/packet_handlers.rs
@@ -1,7 +1,10 @@
 use base::{Position, Text};
 use common::{chat::ChatKind, Game};
 use ecs::{Entity, EntityRef, SysResult};
-use interaction::{handle_interact_entity, handle_player_block_placement, handle_player_digging};
+use interaction::{
+    handle_held_item_change, handle_interact_entity, handle_player_block_placement,
+    handle_player_digging,
+};
 use protocol::{
     packets::{
         client,
@@ -56,6 +59,7 @@ pub fn handle_packet(
             handle_player_block_placement(game, server, packet, player_id)
         }
 
+        ClientPlayPacket::HeldItemChange(packet) => handle_held_item_change(player, packet),
         ClientPlayPacket::InteractEntity(packet) => {
             handle_interact_entity(game, server, packet, player_id)
         }
@@ -89,7 +93,6 @@ pub fn handle_packet(
         | ClientPlayPacket::AdvancementTab(_)
         | ClientPlayPacket::SelectTrade(_)
         | ClientPlayPacket::SetBeaconEffect(_)
-        | ClientPlayPacket::HeldItemChange(_)
         | ClientPlayPacket::UpdateCommandBlock(_)
         | ClientPlayPacket::UpdateCommandBlockMinecart(_)
         | ClientPlayPacket::UpdateJigsawBlock(_)

diff --git a/feather/server/src/packet_handlers/interaction.rs b/feather/server/src/packet_handlers/interaction.rs
@@ -1,14 +1,17 @@
 use crate::{ClientId, NetworkId, Server};
+use common::entities::player::HotbarSlot;
+use common::events::InteractEntityEvent;
 use common::Game;
 use common::{
-    events::{BlockInteractEvent, BlockPlacementEvent, InteractEntityEvent},
+    events::{BlockInteractEvent, BlockPlacementEvent},
     interactable::InteractableRegistry,
 };
-use ecs::{Entity, SysResult};
-use libcraft_core::{BlockFace as LibcraftBlockFace, Hand, InteractionType, Vec3f};
+use ecs::{Entity, EntityRef, SysResult};
+use libcraft_core::{BlockFace as LibcraftBlockFace, Hand};
+use libcraft_core::{InteractionType, Vec3f};
 use protocol::packets::client::{
-    BlockFace, InteractEntity, InteractEntityKind, PlayerBlockPlacement, PlayerDigging,
-    PlayerDiggingStatus,
+    BlockFace, HeldItemChange, InteractEntity, InteractEntityKind, PlayerBlockPlacement,
+    PlayerDigging, PlayerDiggingStatus,
 };
 
 /// Handles the player block placement packet. Currently just removes the block client side for the player.
@@ -193,3 +196,37 @@ pub fn handle_interact_entity(
 
     Ok(())
 }
+
+pub fn handle_held_item_change(player: EntityRef, packet: HeldItemChange) -> SysResult {
+    let new_id = packet.slot as usize;
+    let mut slot = player.get_mut::<HotbarSlot>()?;
+
+    log::trace!("Got player slot change from {} to {}", slot.get(), new_id);
+
+    slot.set(new_id)?;
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use common::Game;
+    use protocol::packets::client::HeldItemChange;
+
+    use super::*;
+
+    #[test]
+    fn held_item_change() {
+        let mut game = Game::new();
+        let entity = game.ecs.spawn((HotbarSlot::new(0),));
+        let player = game.ecs.entity(entity).unwrap();
+
+        let packet = HeldItemChange { slot: 8 };
+
+        handle_held_item_change(player, packet).unwrap();
+
+        assert_eq!(
+            *game.ecs.get::<HotbarSlot>(entity).unwrap(),
+            HotbarSlot::new(8)
+        );
+    }
+}
diff --git a/feather/server/src/systems/player_join.rs b/feather/server/src/systems/player_join.rs
@@ -1,6 +1,7 @@
 use base::{Inventory, Position, Text};
 use common::{
     chat::{ChatKind, ChatPreference},
+    entities::player::HotbarSlot,
     view::View,
     window::BackingWindow,
     ChatBox, Game, Window,
@@ -50,7 +51,8 @@ fn accept_new_player(game: &mut Game, server: &mut Server, client_id: ClientId)
         .add(client.profile().to_vec())
         .add(ChatBox::new(ChatPreference::All))
         .add(inventory)
-        .add(window);
+        .add(window)
+        .add(HotbarSlot::default());
 
     game.spawn_entity(builder);