implement respawning

include/globals.h

@@ -40,6 +40,8 @@ extern uint8_t recv_buffer[256];
 extern uint32_t world_seed;
 extern uint32_t rng_seed;
 
+extern uint64_t world_time;
+
 extern uint16_t client_count;
 
 #pragma pack(push, 1)

include/packets.h

@@ -13,6 +13,7 @@ int cs_setPlayerRotation (int client_fd, float *yaw, float *pitch, uint8_t *on_g
 int cs_setHeldItem (int client_fd);
 int cs_clickContainer (int client_fd);
 int cs_closeContainer (int client_fd);
+int cs_clientStatus (int client_fd);
 
 int sc_loginSuccess (int client_fd, uint8_t *uuid, char *name);
 int sc_knownPacks (int client_fd);
@@ -39,6 +40,7 @@ int sc_setHeadRotation (int client_fd, int id, uint8_t yaw);
 int sc_updateEntityRotation (int client_fd, int id, uint8_t yaw, uint8_t pitch);
 int sc_damageEvent (int client_fd, int id, int type);
 int sc_setHealth (int client_fd, uint8_t health, uint8_t food);
+int sc_respawn (int client_fd);
 int sc_registries (int client_fd);
 
 #endif

include/tools.h

@@ -42,10 +42,12 @@ void setClientState (int client_fd, int new_state);
 int getClientState (int client_fd);
 int getClientIndex (int client_fd);
 
+void resetPlayerData (PlayerData *player);
 int reservePlayerData (int client_fd, uint8_t *uuid, char* name);
 int getPlayerData (int client_fd, PlayerData **output);
 void clearPlayerFD (int client_fd);
 int givePlayerItem (PlayerData *player, uint16_t item, uint8_t count);
+void spawnPlayer (PlayerData *player);
 
 uint8_t serverSlotToClientSlot (int window_id, uint8_t slot);
 uint8_t clientSlotToServerSlot (int window_id, uint8_t slot);

src/globals.c

@@ -29,6 +29,8 @@ uint8_t recv_buffer[256] = {0};
 uint32_t world_seed = 0xA103DE6C;
 uint32_t rng_seed = 0xE2B9419;
 
+uint64_t world_time = 0;
+
 uint16_t client_count;
 
 BlockChange block_changes[20000];

src/main.c

@@ -31,8 +31,6 @@
 #include "worldgen.h"
 #include "registries.h"
 
-uint64_t world_time = 0;
-
 void handlePacket (int client_fd, int length, int packet_id) {
 
   int state = getClientState(client_fd);
@@ -72,66 +70,16 @@ void handlePacket (int client_fd, int length, int packet_id) {
         return;
       } else if (state == STATE_CONFIGURATION) {
         printf("Client Acknowledged Configuration\n\n");
-        setClientState(client_fd, STATE_PLAY);
 
+        // Enter client into "play" state
+        setClientState(client_fd, STATE_PLAY);
         sc_loginPlay(client_fd);
 
         PlayerData *player;
         if (getPlayerData(client_fd, &player)) break;
 
-        float spawn_x = 8.5f, spawn_y = 80.0f, spawn_z = 8.5f;
-        float spawn_yaw = 0.0f, spawn_pitch = 0.0f;
-
-        if (player->y == -32767) { // is this a new player?
-          int _x = 8 / CHUNK_SIZE;
-          int _z = 8 / CHUNK_SIZE;
-          int rx = 8 % CHUNK_SIZE;
-          int rz = 8 % CHUNK_SIZE;
-          spawn_y = getHeightAt(rx, rz, _x, _z, getChunkHash(_x, _z), getChunkBiome(_x, _z)) + 1;
-        } else {
-          spawn_x = player->x > 0 ? (float)player->x + 0.5 : (float)player->x - 0.5;
-          spawn_y = player->y;
-          spawn_z = player->z > 0 ? (float)player->z + 0.5 : (float)player->z - 0.5;
-          spawn_yaw = player->yaw * 180 / 127;
-          spawn_pitch = player->pitch * 90 / 127;
-        }
-
-        sc_synchronizePlayerPosition(client_fd, spawn_x, spawn_y, spawn_z, spawn_yaw, spawn_pitch);
-
-        task_yield();
-
-        for (uint8_t i = 0; i < 41; i ++) {
-          sc_setContainerSlot(client_fd, 0, serverSlotToClientSlot(0, i), player->inventory_count[i], player->inventory_items[i]);
-        }
-        sc_setHeldItem(client_fd, player->hotbar);
-
-        sc_setHealth(client_fd, player->health, player->hunger);
-
-        sc_playerAbilities(client_fd, 0x01 + 0x04); // invulnerability + flight
-        sc_updateTime(client_fd, world_time);
-
-        short _x = player->x / 16, _z = player->z / 16;
-        if (player->x % 16 < 0) _x -= 1;
-        if (player->z % 16 < 0) _z -= 1;
-
-        sc_setDefaultSpawnPosition(client_fd, 8, 80, 8);
-        sc_startWaitingForChunks(client_fd);
-        sc_setCenterChunk(client_fd, _x, _z);
-
-        task_yield();
-
-        // Send spawn chunk first
-        sc_chunkDataAndUpdateLight(client_fd, _x, _z);
-        for (int i = -VIEW_DISTANCE; i <= VIEW_DISTANCE; i ++) {
-          for (int j = -VIEW_DISTANCE; j <= VIEW_DISTANCE; j ++) {
-            if (i == 0 && j == 0) continue;
-            sc_chunkDataAndUpdateLight(client_fd, _x + i, _z + j);
-          }
-        }
-        // Re-synchronize player position after all chunks have been sent
-        sc_synchronizePlayerPosition(client_fd, spawn_x, spawn_y, spawn_z, spawn_yaw, spawn_pitch);
-
-        task_yield();
+        // Send full client spawn sequence
+        spawnPlayer(player);
 
         // Register all existing players and spawn their entities, and broadcast
         // information about the joining player to all existing players.
@@ -156,6 +104,13 @@ void handlePacket (int client_fd, int length, int packet_id) {
       }
       break;
 
+    case 0x0B:
+      if (state == STATE_PLAY) {
+        if (cs_clientStatus(client_fd)) break;
+        return;
+      }
+      break;
+
     case 0x0C:
       if (state == STATE_PLAY) {
         // client tick

src/packets.c

@@ -144,7 +144,7 @@ int sc_finishConfiguration (int client_fd) {
 // S->C Login (play)
 int sc_loginPlay (int client_fd) {
 
-  writeVarInt(client_fd, 69 + sizeVarInt(MAX_PLAYERS));
+  writeVarInt(client_fd, 49 + sizeVarInt(MAX_PLAYERS));
   writeByte(client_fd, 0x2B);
   // entity id
   uint32_t entity_id = getClientIndex(client_fd);
@@ -153,9 +153,9 @@ int sc_loginPlay (int client_fd) {
   writeByte(client_fd, false);
   // dimensions
   writeVarInt(client_fd, 1);
-  writeVarInt(client_fd, 19);
-  const char *dimension = "minecraft:overworld";
-  send_all(client_fd, dimension, 19);
+  writeVarInt(client_fd, 9);
+  const char *dimension = "overworld";
+  send_all(client_fd, dimension, 9);
   // maxplayers
   writeVarInt(client_fd, MAX_PLAYERS);
   // view distance
@@ -171,8 +171,8 @@ int sc_loginPlay (int client_fd) {
   // dimension id
   writeVarInt(client_fd, 0);
   // dimension name
-  writeVarInt(client_fd, 19);
-  send_all(client_fd, dimension, 19);
+  writeVarInt(client_fd, 9);
+  send_all(client_fd, dimension, 9);
   // hashed seed
   writeUint64(client_fd, 0x0123456789ABCDEF);
   // gamemode
@@ -850,6 +850,57 @@ int sc_setHealth (int client_fd, uint8_t health, uint8_t food) {
   return 0;
 }
 
+// S->C Respawn
+int sc_respawn (int client_fd) {
+
+  writeVarInt(client_fd, 28);
+  writeByte(client_fd, 0x4B);
+
+  // dimension id
+  writeVarInt(client_fd, 0);
+  // dimension name
+  const char *dimension = "overworld";
+  writeVarInt(client_fd, 9);
+  send_all(client_fd, dimension, 9);
+  // hashed seed
+  writeUint64(client_fd, 0x0123456789ABCDEF);
+  // gamemode
+  writeByte(client_fd, GAMEMODE);
+  // previous gamemode
+  writeByte(client_fd, 0xFF);
+  // is debug
+  writeByte(client_fd, 0);
+  // is flat
+  writeByte(client_fd, 0);
+  // has death location
+  writeByte(client_fd, 0);
+  // portal cooldown
+  writeVarInt(client_fd, 0);
+  // sea level
+  writeVarInt(client_fd, 63);
+  // data kept
+  writeByte(client_fd, 0);
+
+  return 0;
+}
+
+// C->S Client Status
+int cs_clientStatus (int client_fd) {
+
+  uint8_t id = readByte(client_fd);
+
+  PlayerData *player;
+  if (getPlayerData(client_fd, &player)) return 1;
+
+  if (id == 0) {
+    sc_respawn(client_fd);
+    resetPlayerData(player);
+    spawnPlayer(player);
+  }
+
+  return 0;
+}
+
 // S->C Registry Data (multiple packets) and Update Tags (configuration, multiple packets)
 int sc_registries (int client_fd) {
 

src/tools.c

@@ -218,6 +218,21 @@ int getClientIndex (int client_fd) {
   return -1;
 }
 
+void resetPlayerData (PlayerData *player) {
+  player->health = 20;
+  player->hunger = 20;
+  player->y = -32767;
+  player->grounded_y = 0;
+  for (int i = 0; i < 41; i ++) {
+    player->inventory_items[i] = 0;
+    player->inventory_count[i] = 0;
+  }
+  for (int i = 0; i < 9; i ++) {
+    player->craft_items[i] = 0;
+    player->craft_count[i] = 0;
+  }
+}
+
 int reservePlayerData (int client_fd, uint8_t *uuid, char *name) {
 
   for (int i = 0; i < MAX_PLAYERS; i ++) {
@@ -237,9 +252,7 @@ int reservePlayerData (int client_fd, uint8_t *uuid, char *name) {
       player_data[i].client_fd = client_fd;
       memcpy(player_data[i].uuid, uuid, 16);
       memcpy(player_data[i].name, name, 16);
-      player_data[i].health = 20;
-      player_data[i].hunger = 20;
-      player_data[i].y = -32767;
+      resetPlayerData(&player_data[i]);
       return 0;
     }
   }
@@ -357,6 +370,72 @@ int givePlayerItem (PlayerData *player, uint16_t item, uint8_t count) {
 
 }
 
+// Sends the full sequence for spawning the player to the client
+void spawnPlayer (PlayerData *player) {
+
+  // Player spawn coordinates, initialized to placeholders
+  float spawn_x = 8.5f, spawn_y = 80.0f, spawn_z = 8.5f;
+  float spawn_yaw = 0.0f, spawn_pitch = 0.0f;
+
+  if (player->y == -32767) { // Is this a new player?
+    // Determine spawning Y coordinate based on terrain height
+    int _x = 8 / CHUNK_SIZE;
+    int _z = 8 / CHUNK_SIZE;
+    int rx = 8 % CHUNK_SIZE;
+    int rz = 8 % CHUNK_SIZE;
+    spawn_y = getHeightAt(rx, rz, _x, _z, getChunkHash(_x, _z), getChunkBiome(_x, _z)) + 1;
+  } else { // Not a new player
+    // Calculate spawn position from player data
+    spawn_x = player->x > 0 ? (float)player->x + 0.5 : (float)player->x - 0.5;
+    spawn_y = player->y;
+    spawn_z = player->z > 0 ? (float)player->z + 0.5 : (float)player->z - 0.5;
+    spawn_yaw = player->yaw * 180 / 127;
+    spawn_pitch = player->pitch * 90 / 127;
+  }
+
+  // Teleport player to spawn coordinates (first pass)
+  sc_synchronizePlayerPosition(player->client_fd, spawn_x, spawn_y, spawn_z, spawn_yaw, spawn_pitch);
+
+  task_yield(); // Check task timer between packets
+
+  // Sync client inventory and hotbar
+  for (uint8_t i = 0; i < 41; i ++) {
+    sc_setContainerSlot(player->client_fd, 0, serverSlotToClientSlot(0, i), player->inventory_count[i], player->inventory_items[i]);
+  }
+  sc_setHeldItem(player->client_fd, player->hotbar);
+  // Sync client health and hunger
+  sc_setHealth(player->client_fd, player->health, player->hunger);
+  // Sync client clock time
+  sc_updateTime(player->client_fd, world_time);
+
+  // Give the player flight (for testing)
+  sc_playerAbilities(player->client_fd, 0x04);
+
+  // Calculate player's chunk coordinates
+  short _x = div_floor(player->x, 16), _z = div_floor(player->z, 16);
+
+  // Indicate that we're about to send chunk data
+  sc_setDefaultSpawnPosition(player->client_fd, 8, 80, 8);
+  sc_startWaitingForChunks(player->client_fd);
+  sc_setCenterChunk(player->client_fd, _x, _z);
+
+  task_yield(); // Check task timer between packets
+
+  // Send spawn chunk first
+  sc_chunkDataAndUpdateLight(player->client_fd, _x, _z);
+  for (int i = -VIEW_DISTANCE; i <= VIEW_DISTANCE; i ++) {
+    for (int j = -VIEW_DISTANCE; j <= VIEW_DISTANCE; j ++) {
+      if (i == 0 && j == 0) continue;
+      sc_chunkDataAndUpdateLight(player->client_fd, _x + i, _z + j);
+    }
+  }
+  // Re-teleport player after all chunks have been sent
+  sc_synchronizePlayerPosition(player->client_fd, spawn_x, spawn_y, spawn_z, spawn_yaw, spawn_pitch);
+
+  task_yield(); // Check task timer between packets
+
+}
+
 uint8_t getBlockChange (short x, uint8_t y, short z) {
   for (int i = 0; i < block_changes_count; i ++) {
     if (block_changes[i].block == 0xFF) continue;