alexander.nutz/barecopper
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add player entities

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This commit is contained in:
p2r3
2025-08-20 04:30:29 +03:00
parent 293ed517ea
commit 66ab597ad0
7 changed files with 238 additions and 22 deletions
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2
src/globals.c
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@@ -11,6 +11,8 @@ uint8_t recv_buffer[256] = {0};
uint32_t world_seed = 0xA103DE6C;
uint32_t rng_seed = 0xE2B9419;
uint16_t client_count;
BlockChange block_changes[20000];
int block_changes_count = 0;

10
src/globals.h
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@@ -24,6 +24,10 @@
// How many visited chunks to "remember"
// The server will not re-send chunks that the player has recently been in
#define VISITED_HISTORY 4
// If defined, scales the frequency at which player movement updates are
// broadcast based on the amount of players, reducing overhead for higher
// player counts. For very many players, makes movement look jittery.
#define SCALE_MOVEMENT_UPDATES_TO_PLAYER_COUNT
#define STATE_NONE 0
#define STATE_STATUS 1
@@ -38,6 +42,8 @@ extern uint8_t recv_buffer[256];
extern uint32_t world_seed;
extern uint32_t rng_seed;
extern uint16_t client_count;
#pragma pack(push, 1)
typedef struct {
@@ -49,12 +55,16 @@ typedef struct {
typedef struct {
uint8_t uuid[16];
char name[16];
int client_fd;
short x;
short y;
short z;
short visited_x[VISITED_HISTORY];
short visited_z[VISITED_HISTORY];
#ifdef SCALE_MOVEMENT_UPDATES_TO_PLAYER_COUNT
uint16_t packets_since_update;
#endif
int8_t yaw;
int8_t pitch;
uint8_t hotbar;

74
src/main.c
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@@ -43,9 +43,11 @@ void handlePacket (int client_fd, int length, int packet_id) {
if (cs_handshake(client_fd)) break;
return;
} else if (state == STATE_LOGIN) {
if (cs_loginStart(client_fd)) break;
if (reservePlayerData(client_fd, (char *)(recv_buffer + 17))) break;
if (sc_loginSuccess(client_fd, (char *)recv_buffer, (char *)(recv_buffer + 17))) break;
uint8_t uuid[16];
char name[16];
if (cs_loginStart(client_fd, uuid, name)) break;
if (reservePlayerData(client_fd, uuid, name)) break;
if (sc_loginSuccess(client_fd, uuid, name)) break;
return;
} else if (state == STATE_CONFIGURATION) {
if (cs_clientInformation(client_fd)) break;
@@ -122,6 +124,17 @@ void handlePacket (int client_fd, int length, int packet_id) {
// Re-synchronize player position after all chunks have been sent
sc_synchronizePlayerPosition(client_fd, spawn_x, spawn_y, spawn_z, spawn_yaw, spawn_pitch);
// Register all existing players and spawn their entities, and broadcast
// information about the joining player to all existing players.
for (int i = 0; i < MAX_PLAYERS; i ++) {
if (player_data[i].client_fd == -1) continue;
sc_playerInfoUpdateAddPlayer(client_fd, player_data[i]);
if (player_data[i].client_fd == client_fd) continue;
sc_playerInfoUpdateAddPlayer(player_data[i].client_fd, *player);
sc_spawnEntityPlayer(client_fd, player_data[i]);
sc_spawnEntityPlayer(player_data[i].client_fd, *player);
}
return;
}
break;
@@ -157,6 +170,7 @@ void handlePacket (int client_fd, int length, int packet_id) {
case 0x1D:
case 0x1E:
case 0x1F:
if (state == STATE_PLAY) {
double x, y, z;
@@ -164,27 +178,63 @@ 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);
else if (packet_id == 0x1F) cs_setPlayerRotation (client_fd, &yaw, &pitch);
else cs_setPlayerPositionAndRotation(client_fd, &x, &y, &z, &yaw, &pitch);
// Cast the values to short to get integer position
short cx = x, cy = y, cz = z;
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;
}
// Broadcast player position to other players
#ifdef SCALE_MOVEMENT_UPDATES_TO_PLAYER_COUNT
// If applicable, broadcast only every client_count-th movement update
uint8_t should_broadcast = false;
if (player->packets_since_update++ == client_count) {
should_broadcast = true;
player->packets_since_update = 0;
}
#else
#define should_broadcast (client_count > 0)
#endif
if (should_broadcast) {
// If the packet had no rotation data, calculate it from player data
if (packet_id == 0x1D) {
yaw = player->yaw * 180 / 127;
pitch = player->pitch * 90 / 127;
}
// Send current position data to all connected players
for (int i = 0; i < MAX_PLAYERS; i ++) {
if (player_data[i].client_fd == -1) continue;
if (player_data[i].client_fd == client_fd) continue;
if (packet_id == 0x1F) {
sc_updateEntityRotation(player_data[i].client_fd, client_fd, player->yaw, player->pitch);
} else {
sc_teleportEntity(player_data[i].client_fd, client_fd, x, y, z, yaw, pitch);
}
sc_setHeadRotation(player_data[i].client_fd, client_fd, player->yaw);
}
}
// Don't continue if all we got was rotation data
if (packet_id == 0x1F) return;
// Cast the values to short to get integer position
short cx = x, cy = y, cz = z;
// Determine the player's chunk coordinates
short _x = (cx < 0 ? cx - 16 : cx) / 16, _z = (cz < 0 ? cz - 16 : cz) / 16;
// Calculate distance between previous and current chunk coordinates
short dx = _x - (player->x < 0 ? player->x - 16 : player->x) / 16;
short dz = _z - (player->z < 0 ? player->z - 16 : player->z) / 16;
// Update position (and rotation) in player data
// Update position in player data
player->x = cx;
player->y = cy;
player->z = cz;
if (packet_id == 0x1E) {
player->yaw = ((short)(yaw + 540) % 360 - 180) * 127 / 180;
player->pitch = pitch / 90.0f * 127.0f;
}
// Exit early if no chunk borders were crossed
if (dx == 0 && dz == 0) return;
@@ -269,6 +319,8 @@ void handlePacket (int client_fd, int length, int packet_id) {
}
void disconnectClient (int *client_fd, int cause) {
if (*client_fd == -1) return;
client_count --;
setClientState(*client_fd, STATE_NONE);
clearPlayerFD(*client_fd);
close(*client_fd);
@@ -290,6 +342,7 @@ int main () {
for (int i = 0; i < MAX_PLAYERS; i ++) {
clients[i] = -1;
client_states[i * 2] = -1;
player_data[i].client_fd = -1;
}
// Create socket
@@ -350,6 +403,7 @@ int main () {
printf("New client, fd: %d\n", clients[i]);
int flags = fcntl(clients[i], F_GETFL, 0);
fcntl(clients[i], F_SETFL, flags | O_NONBLOCK);
client_count ++;
}
break;
}

155
src/packets.c
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@@ -36,27 +36,28 @@ int cs_handshake (int client_fd) {
}
// C->S Login Start
// Leaves player name and UUID at indexes 0 and 17 of recv_buffer, respectively
int cs_loginStart (int client_fd) {
int cs_loginStart (int client_fd, uint8_t *uuid, char *name) {
printf("Received Login Start:\n");
readString(client_fd);
if (recv_count == -1) return 1;
printf(" Player name: %s\n", recv_buffer);
recv_count = recv_all(client_fd, recv_buffer + 17, 16, false);
memcpy(name, recv_buffer, strlen((char *)recv_buffer) + 1);
printf(" Player name: %s\n", name);
recv_count = recv_all(client_fd, recv_buffer, 16, false);
if (recv_count == -1) return 1;
memcpy(uuid, recv_buffer, 16);
printf(" Player UUID: ");
for (int i = 17; i < 33; i ++) printf("%x", recv_buffer[i]);
for (int i = 0; i < 16; i ++) printf("%x", uuid[i]);
printf("\n\n");
return 0;
}
// S->C Login Success
int sc_loginSuccess (int client_fd, char *name, char *uuid) {
int sc_loginSuccess (int client_fd, uint8_t *uuid, char *name) {
printf("Sending Login Success...\n\n");
int name_length = strlen(name);
uint8_t name_length = strlen(name);
writeVarInt(client_fd, 1 + 16 + sizeVarInt(name_length) + name_length + 1);
writeVarInt(client_fd, 0x02);
send(client_fd, uuid, 16, 0);
@@ -649,6 +650,19 @@ int cs_setPlayerPosition (int client_fd, double *x, double *y, double *z) {
}
// C->S Set Player Rotation
int cs_setPlayerRotation (int client_fd, float *yaw, float *pitch) {
*yaw = readFloat(client_fd);
*pitch = readFloat(client_fd);
// ignore flags
readByte(client_fd);
return 0;
}
// C->S Set Held Item (serverbound)
int cs_setHeldItem (int client_fd) {
@@ -691,6 +705,133 @@ int cs_closeContainer (int client_fd) {
return 0;
}
// S->C Player Info Update, "Add Player" action
int sc_playerInfoUpdateAddPlayer (int client_fd, PlayerData player) {
writeVarInt(client_fd, 21 + strlen(player.name)); // Packet length
writeByte(client_fd, 0x3F); // Packet ID
writeByte(client_fd, 0x01); // EnumSet: Add Player
writeByte(client_fd, 1); // Player count (1 per packet)
// Player UUID
send(client_fd, player.uuid, 16, 0);
// Player name
writeByte(client_fd, strlen(player.name));
send(client_fd, player.name, strlen(player.name), 0);
// Properties (don't send any)
writeByte(client_fd, 0);
return 0;
}
// S->C Spawn Entity
int sc_spawnEntity (
int client_fd,
int id, uint8_t *uuid, int type,
double x, double y, double z,
uint8_t yaw, uint8_t pitch
) {
writeVarInt(client_fd, 51 + sizeVarInt(id) + sizeVarInt(type));
writeByte(client_fd, 0x01);
writeVarInt(client_fd, id); // Entity ID
send(client_fd, uuid, 16, 0); // Entity UUID
writeVarInt(client_fd, type); // Entity type
// Position
writeDouble(client_fd, x);
writeDouble(client_fd, y);
writeDouble(client_fd, z);
// Angles
writeByte(client_fd, yaw);
writeByte(client_fd, pitch);
writeByte(client_fd, yaw);
// Data - mostly unused
writeByte(client_fd, 0);
// Velocity
writeUint16(client_fd, 0);
writeUint16(client_fd, 0);
writeUint16(client_fd, 0);
return 0;
}
// S->C Spawn Entity (from PlayerData)
int sc_spawnEntityPlayer (int client_fd, PlayerData player) {
return sc_spawnEntity(
client_fd,
player.client_fd, player.uuid, 149,
player.x > 0 ? (double)player.x + 0.5 : (double)player.x - 0.5,
player.y,
player.z > 0 ? (double)player.z + 0.5 : (float)player.z - 0.5,
player.yaw, player.pitch
);
}
// S->C Teleport Entity
int sc_teleportEntity (
int client_fd, int id,
double x, double y, double z,
float yaw, float pitch
) {
// Packet length and ID
writeVarInt(client_fd, 58 + sizeVarInt(id));
writeByte(client_fd, 0x1F);
// Entity ID
writeVarInt(client_fd, id);
// Position
writeDouble(client_fd, x);
writeDouble(client_fd, y);
writeDouble(client_fd, z);
// Velocity
writeUint64(client_fd, 0);
writeUint64(client_fd, 0);
writeUint64(client_fd, 0);
// Angles
writeFloat(client_fd, yaw);
writeFloat(client_fd, pitch);
// On ground flag
writeByte(client_fd, 1);
return 0;
}
int sc_setHeadRotation (int client_fd, int id, uint8_t yaw) {
// Packet length and ID
writeByte(client_fd, 2 + sizeVarInt(id));
writeByte(client_fd, 0x4C);
// Entity ID
writeVarInt(client_fd, id);
// Head yaw
writeByte(client_fd, yaw);
return 0;
}
int sc_updateEntityRotation (int client_fd, int id, uint8_t yaw, uint8_t pitch) {
// Packet length and ID
writeByte(client_fd, 4 + sizeVarInt(id));
writeByte(client_fd, 0x31);
// Entity ID
writeVarInt(client_fd, id);
// Angles
writeByte(client_fd, yaw);
writeByte(client_fd, pitch);
// "On ground" flag
writeByte(client_fd, 1);
return 0;
}
// S->C Registry Data (multiple packets) and Update Tags (configuration, multiple packets)
int sc_registries (int client_fd) {

11
src/packets.h
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@@ -2,18 +2,19 @@
#define H_PACKETS
int cs_handshake (int client_fd);
int cs_loginStart (int client_fd);
int cs_loginStart (int client_fd, uint8_t *uuid, char *name);
int cs_clientInformation (int client_fd);
int cs_pluginMessage (int client_fd);
int cs_playerAction (int client_fd);
int cs_useItemOn (int client_fd);
int cs_setPlayerPositionAndRotation (int client_fd, double *x, double *y, double *z, float *yaw, float *pitch);
int cs_setPlayerPosition (int client_fd, double *x, double *y, double *z);
int cs_setPlayerRotation(int client_fd, float *yaw, float *pitch);
int cs_setHeldItem (int client_fd);
int cs_clickContainer (int client_fd);
int cs_closeContainer (int client_fd);
int sc_loginSuccess (int client_fd, char *name, char *uuid);
int sc_loginSuccess (int client_fd, uint8_t *uuid, char *name);
int sc_knownPacks (int client_fd);
int sc_finishConfiguration (int client_fd);
int sc_loginPlay (int client_fd);
@@ -30,6 +31,12 @@ int sc_setHeldItem (int client_fd, uint8_t slot);
int sc_blockUpdate (int client_fd, int64_t x, int64_t y, int64_t z, uint8_t block);
int sc_openScreen (int client_fd, uint8_t window, const char *title, uint16_t length);
int sc_acknowledgeBlockChange (int client_fd, int sequence);
int sc_playerInfoUpdateAddPlayer (int client_fd, PlayerData player);
int sc_spawnEntity (int client_fd, int id, uint8_t *uuid, int type, double x, double y, double z, double yaw, double pitch);
int sc_spawnEntityPlayer (int client_fd, PlayerData player);
int sc_teleportEntity (int client_fd, int id, double x, double y, double z, float yaw, float pitch);
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_registries(int client_fd);
#endif

6
src/tools.c
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@@ -195,11 +195,12 @@ int getClientIndex (int client_fd) {
return -1;
}
int reservePlayerData (int client_fd, char *uuid) {
int reservePlayerData (int client_fd, uint8_t *uuid, char *name) {
for (int i = 0; i < MAX_PLAYERS; i ++) {
if (memcmp(player_data[i].uuid, uuid, 16) == 0) {
player_data[i].client_fd = client_fd;
memcpy(player_data[i].name, name, 16);
return 0;
}
uint8_t empty = true;
@@ -212,6 +213,7 @@ int reservePlayerData (int client_fd, char *uuid) {
if (empty) {
player_data[i].client_fd = client_fd;
memcpy(player_data[i].uuid, uuid, 16);
memcpy(player_data[i].name, name, 16);
player_data[i].y = -32767;
return 0;
}
@@ -234,7 +236,7 @@ int getPlayerData (int client_fd, PlayerData **output) {
void clearPlayerFD (int client_fd) {
for (int i = 0; i < MAX_PLAYERS; i ++) {
if (player_data[i].client_fd == client_fd) {
player_data[i].client_fd = 0;
player_data[i].client_fd = -1;
return;
}
}

2
src/tools.h
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@@ -34,7 +34,7 @@ void setClientState (int client_fd, int new_state);
int getClientState (int client_fd);
int getClientIndex (int client_fd);
int reservePlayerData (int client_fd, char *uuid);
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);