From f1a7d8478e8cbae794057c5cf4aba9933088d4ac Mon Sep 17 00:00:00 2001
From: SamB440 <sam@islandearth.net>
Date: Thu, 23 May 2024 12:29:46 +0100
Subject: [PATCH] Fix some respawn issues for modern clients

---
 .../events/packets/PacketPlayerRespawn.java   | 49 ++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java
index a439b702ed..3c39526e6c 100644
--- a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java
+++ b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java
@@ -24,12 +24,39 @@
 import java.util.List;
 import java.util.Objects;
 
+/**
+ * PlayerRespawnS2CPacket info (1.20.2+):
+ * If the world is different (check via registry key), world is recreated (all entities etc destroyed).
+ * <p>
+ * Client player is ALWAYS recreated
+ * <p>
+ * If the packet has the `KEEP_TRACKED_DATA` flag:
+ * Sneaking and Sprinting fields are kept on the new client player.
+ * <p>
+ * If the packet has the `KEEP_ATTRIBUTES` flag:
+ * Attributes are kept.
+ * <p>
+ * New client player is initialised:
+ * Pose is set to standing.
+ * Velocity is set to zero.
+ * Pitch is set to 0.
+ * Yaw is set to -180.
+ */
+// TODO update for 1.20.2-
 public class PacketPlayerRespawn extends PacketListenerAbstract {
 
     public PacketPlayerRespawn() {
         super(PacketListenerPriority.HIGH);
     }
 
+    private static final byte KEEP_ATTRIBUTES = 1;
+    private static final byte KEEP_TRACKED_DATA = 2;
+    private static final byte KEEP_ALL = 3;
+
+    private boolean hasFlag(WrapperPlayServerRespawn respawn, byte flag) {
+        return (respawn.getKeptData() & flag) != 0;
+    }
+
     @Override
     public void onPacketSend(PacketSendEvent event) {
         if (event.getPacketType() == PacketType.Play.Server.UPDATE_HEALTH) {
@@ -101,11 +128,17 @@ public void onPacketSend(PacketSendEvent event) {
             player.latencyUtils.addRealTimeTask(player.lastTransactionSent.get() + 1, () -> {
                 player.isSneaking = false;
                 player.lastOnGround = false;
+                player.onGround = false;
                 player.isInBed = false;
                 player.packetStateData.packetPlayerOnGround = false; // If somewhere else pulls last ground to fix other issues
                 player.packetStateData.lastClaimedPosition = new Vector3d();
                 player.filterMojangStupidityOnMojangStupidity = new Vector3d();
-                player.lastSprintingForSpeed = false; // This is reverted even on 1.18 clients
+
+                if (player.getClientVersion().isNewerThanOrEquals(ClientVersion.V_1_19_4)) {
+                    player.isSprinting = !this.hasFlag(respawn, KEEP_TRACKED_DATA);
+                } else {
+                    player.lastSprintingForSpeed = false;
+                }
 
                 player.checkManager.getPacketCheck(BadPacketsE.class).handleRespawn(); // Reminder ticks reset
 
@@ -141,6 +174,20 @@ public void onPacketSend(PacketSendEvent event) {
                 if (PacketEvents.getAPI().getServerManager().getVersion().isNewerThanOrEquals(ServerVersion.V_1_17)) {
                     player.compensatedWorld.setDimension(respawn.getDimension(), event.getUser());
                 }
+
+                // TODO this needs to be done for other client versions as well. And there should probably be some attribute holder that we can just call reset() on.
+                if (player.getClientVersion().isNewerThanOrEquals(ClientVersion.V_1_20_5) && !this.hasFlag(respawn, KEEP_ATTRIBUTES)) {
+                    // Reset attributes if not kept
+                    final PacketEntitySelf self = player.compensatedEntities.getSelf();
+                    self.gravityAttribute = 0.08d;
+                    self.stepHeight = 0.6f;
+                    self.scale = 1.0f;
+                    self.setJumpStrength(0.42f);
+                    self.setBreakSpeedMultiplier(1.0f);
+                    self.setBlockInteractRange(4.5);
+                    self.setEntityInteractRange(3.0);
+                    player.compensatedEntities.hasSprintingAttributeEnabled = false;
+                }
             });
         }
     }