Initial commit

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "azalea-hax"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+azalea = { git = "https://github.com/mat-1/azalea" }
+# azalea = { path = "../azalea/azalea" }

README.md

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+# Azalea Hax
+
+An [Azalea](https://github.com/azalea-rs/azalea) plugin with useful features that will probably trigger anticheats.
+
+## Features
+
+- Anti-knockback

src/lib.rs

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+use azalea::{
+    app::{App, Plugin, PreUpdate},
+    ecs::prelude::*,
+    entity::indexing::EntityIdIndex,
+    packet_handling::game::PacketEvent,
+    prelude::*,
+    protocol::packets::game::ClientboundGamePacket,
+    world::MinecraftEntityId,
+};
+
+pub struct HaxPlugin;
+impl Plugin for HaxPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(
+            PreUpdate,
+            anti_knockback
+                .before(azalea::packet_handling::game::process_packet_events)
+                .after(azalea::packet_handling::game::send_packet_events),
+        );
+    }
+}
+
+pub trait HaxClientExt {
+    fn has_anti_knockback(&self) -> bool;
+    /// Enable or disable anti-knockback for this client. If enabled, then the server won't be able
+    /// to change this client's velocity.
+    fn set_anti_knockback(&self, value: bool);
+}
+
+impl HaxClientExt for azalea::Client {
+    fn has_anti_knockback(&self) -> bool {
+        self.get_component::<AntiKnockback>().is_some()
+    }
+
+    fn set_anti_knockback(&self, enabled: bool) {
+        let mut ecs = self.ecs.lock();
+        let mut entity_mut = ecs.entity_mut(self.entity);
+        if enabled {
+            entity_mut.insert(AntiKnockback);
+        } else {
+            entity_mut.remove::<AntiKnockback>();
+        }
+    }
+}
+
+/// The component that controls whether we have anti-knockback or not.
+#[derive(Component, Clone)]
+pub struct AntiKnockback;
+
+fn anti_knockback(
+    events: ResMut<Events<PacketEvent>>,
+    player_query: Query<&EntityIdIndex>,
+    entity_query: Query<(), With<AntiKnockback>>,
+) {
+    // bevy please merge this https://github.com/bevyengine/bevy/pull/8051
+    // :pleading:
+    #[allow(invalid_reference_casting)]
+    for event in events
+        .iter_current_update_events()
+        // you didn't see anything
+        .map(|e| unsafe { &mut *(e as *const PacketEvent as *mut PacketEvent) })
+    {
+        if let ClientboundGamePacket::SetEntityMotion(p) = &mut event.packet {
+            let Ok(entity_id_index) = player_query.get(event.entity) else {
+                continue;
+            };
+            let Some(ecs_entity) = entity_id_index.get(&MinecraftEntityId(p.id)) else {
+                continue;
+            };
+            // only apply if the entity has the AntiKnockback component
+            if entity_query.get(ecs_entity).is_ok() {
+                (p.xa, p.ya, p.za) = (0, 0, 0);
+            }
+        } else if let ClientboundGamePacket::Explode(p) = &mut event.packet {
+            // only apply if the entity has the AntiKnockback component
+            if entity_query.get(event.entity).is_ok() {
+                (p.knockback_x, p.knockback_y, p.knockback_z) = (0., 0., 0.);
+            }
+        }
+    }
+}