From 6fc5d07699d3c68a653821af3a6d6cf8fca8e719 Mon Sep 17 00:00:00 2001
From: p2r3 <p2r3@p2r3.com>
Date: Fri, 22 Aug 2025 13:41:19 +0300
Subject: [PATCH] support common miscellaneous packets

---
 include/packets.h |  1 +
 src/main.c        | 26 ++++++++++++++++++++------
 src/packets.c     |  7 +++++++
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/include/packets.h b/include/packets.h
index 98db4dc..9fa5632 100644
--- a/include/packets.h
+++ b/include/packets.h
@@ -10,6 +10,7 @@ int cs_useItemOn (int client_fd);
 int cs_setPlayerPositionAndRotation (int client_fd, double *x, double *y, double *z, float *yaw, float *pitch, uint8_t *on_ground);
 int cs_setPlayerPosition (int client_fd, double *x, double *y, double *z, uint8_t *on_ground);
 int cs_setPlayerRotation (int client_fd, float *yaw, float *pitch, uint8_t *on_ground);
+int cs_setPlayerMovementFlags (int client_fd, uint8_t *on_ground);
 int cs_setHeldItem (int client_fd);
 int cs_clickContainer (int client_fd);
 int cs_closeContainer (int client_fd);
diff --git a/src/main.c b/src/main.c
index 915daa8..1f80d5d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -157,9 +157,19 @@ void handlePacket (int client_fd, int length, int packet_id) {
       }
       break;
 
+    case 0x1B: {
+      if (state == STATE_PLAY) {
+        // Serverbound keep-alive (ignored)
+        recv_all(client_fd, recv_buffer, 8, false);
+        return;
+      }
+      break;
+    }
+
     case 0x1D:
     case 0x1E:
     case 0x1F:
+    case 0x20:
       if (state == STATE_PLAY) {
 
         double x, y, z;
@@ -169,17 +179,12 @@ void handlePacket (int client_fd, int length, int packet_id) {
         // Read player position (and rotation)
         if (packet_id == 0x1D) cs_setPlayerPosition(client_fd, &x, &y, &z, &on_ground);
         else if (packet_id == 0x1F) cs_setPlayerRotation (client_fd, &yaw, &pitch, &on_ground);
+        else if (packet_id == 0x20) cs_setPlayerMovementFlags (client_fd, &on_ground);
         else cs_setPlayerPositionAndRotation(client_fd, &x, &y, &z, &yaw, &pitch, &on_ground);
 
         PlayerData *player;
         if (getPlayerData(client_fd, &player)) break;
 
-        // Update rotation in player data (if applicable)
-        if (packet_id != 0x1D) {
-          player->yaw = ((short)(yaw + 540) % 360 - 180) * 127 / 180;
-          player->pitch = pitch / 90.0f * 127.0f;
-        }
-
         // Handle fall damage
         if (on_ground) {
           int8_t damage = player->grounded_y - player->y - 3;
@@ -192,6 +197,15 @@ void handlePacket (int client_fd, int length, int packet_id) {
           player->grounded_y = player->y;
         }
 
+        // Don't continue if all we got were flags
+        if (packet_id == 0x20) return;
+
+        // Update rotation in player data (if applicable)
+        if (packet_id != 0x1D) {
+          player->yaw = ((short)(yaw + 540) % 360 - 180) * 127 / 180;
+          player->pitch = pitch / 90.0f * 127.0f;
+        }
+
         // Broadcast player position to other players
         #ifdef SCALE_MOVEMENT_UPDATES_TO_PLAYER_COUNT
           // If applicable, broadcast only every client_count-th movement update
diff --git a/src/packets.c b/src/packets.c
index 96aa18f..30d0637 100644
--- a/src/packets.c
+++ b/src/packets.c
@@ -651,6 +651,13 @@ int cs_setPlayerRotation (int client_fd, float *yaw, float *pitch, uint8_t *on_g
   return 0;
 }
 
+int cs_setPlayerMovementFlags (int client_fd, uint8_t *on_ground) {
+
+  *on_ground = readByte(client_fd) & 0x01;
+
+  return 0;
+}
+
 // C->S Set Held Item (serverbound)
 int cs_setHeldItem (int client_fd) {