Initial flight implementation

Author: mmvanheusden

common/src/main/kotlin/com/lambda/module/modules/movement/Flight.kt

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2025 Lambda
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lambda.module.modules.movement
+
+import com.lambda.event.events.MovementEvent
+import com.lambda.event.events.PacketEvent
+import com.lambda.event.listener.SafeListener.Companion.listen
+import com.lambda.module.tag.ModuleTag
+import com.lambda.module.Module
+import com.lambda.util.Communication.debug
+import com.lambda.util.Communication.info
+import com.lambda.util.NamedEnum
+import net.minecraft.network.packet.c2s.play.UpdatePlayerAbilitiesC2SPacket
+import net.minecraft.network.packet.s2c.play.PlayerAbilitiesS2CPacket
+
+
+object Flight : Module(
+    name = "Flight",
+    description = "Allows you to fly",
+    defaultTags = setOf(ModuleTag.MOVEMENT)
+) {
+    val mode by setting("Mode", Mode.CREATIVE);
+
+    private val speed by setting("Speed", 1.0, 0.1..5.0, 0.01)
+
+    // Creative
+    private val preventDisable by setting("Prevent Disable", true, description = "Prevent the server from disabling the flying ability") { mode == Mode.CREATIVE }
+    private val conceal by setting("Conceal", true, description = "Cancels outgoing player ability update packets") { mode == Mode.CREATIVE }
+    private val onlyAllow by setting("Only Allow", false, description = "Allows you to fly just like in creative mode") { mode == Mode.CREATIVE }
+
+    data class Abilities(val flyingAllowed: Boolean, val flySpeed: Float)
+
+    private var preAbilities = Abilities(false, 0.15F) // Store if server allows us to fly so we don't break flying ability after disabling
+
+    enum class Mode(override val displayName: String) : NamedEnum {
+        GROUNDSPOOF("Ground spoof"), // TODO: Implement
+        CREATIVE("Creative"),
+    }
+
+
+    init {
+        // Cancel packets that disable flying state/ability
+        listen<PacketEvent.Receive.Pre> { event ->
+            if (!preventDisable) return@listen
+            val packet = event.packet
+            if (packet is PlayerAbilitiesS2CPacket) {
+                // If the server attempts to enforce the abilities present before toggling, cancel
+                if (packet.allowFlying() == preAbilities.flyingAllowed || packet.isFlying != isEnabled) {
+                    info("server tried to cancel flight")
+                    debug(packet.toString())
+                    event.cancel()
+                }
+            }
+        }
+
+        // Prevent outgoing player ability updates because it will stand out when a survival player starts flying
+        listen<PacketEvent.Send.Pre> { event ->
+            if (!conceal) return@listen
+            val packet = event.packet
+            if (packet is UpdatePlayerAbilitiesC2SPacket) {
+                debug(packet.toString())
+                event.cancel()
+            }
+        }
+
+        listen<MovementEvent.Player.Pre> { event ->
+            when (mode) {
+                Mode.GROUNDSPOOF -> {
+                }
+
+                Mode.CREATIVE -> {
+                    player.abilities.allowFlying = true
+                    if (!onlyAllow) {
+                        player.abilities.flying = true
+                        player.abilities.flySpeed = 0.05F * speed.toFloat()
+                    }
+                }
+            }
+        }
+
+        onEnable {
+            when (mode) {
+                Mode.GROUNDSPOOF -> {
+                }
+
+                Mode.CREATIVE -> {
+                    preAbilities = Abilities(player.abilities.allowFlying,player.abilities.flySpeed)
+                    player.abilities.allowFlying = true;
+                    if (!onlyAllow) player.abilities.flying = true;
+                }
+            }
+        }
+
+        onDisable {
+            when (mode) {
+                Mode.GROUNDSPOOF -> {
+                }
+
+                Mode.CREATIVE -> {
+                    player.abilities.flying = false;
+
+                    // Set abilities back to server defaults
+                    player.abilities.allowFlying = preAbilities.flyingAllowed
+                    player.abilities.flySpeed = preAbilities.flySpeed
+                }
+            }
+        }
+    }
+}