support placing blocks on containers while sneaking

include/globals.h

@@ -95,6 +95,7 @@ typedef struct {
   uint8_t craft_count[9];
   // 0x01 - attack cooldown
   // 0x02 - has not spawned yet
+  // 0x04 - sneaking
   uint8_t flags;
 } PlayerData;
 

include/packets.h

@@ -49,6 +49,7 @@ int sc_systemChat (int client_fd, char* message, uint16_t len);
 int cs_interact (int client_fd);
 int sc_entityEvent (int client_fd, int entity_id, uint8_t status);
 int sc_removeEntity (int client_fd, int entity_id);
+int cs_playerInput (int client_fd);
 int sc_registries (int client_fd);
 
 #endif

src/main.c

@@ -335,6 +335,10 @@ void handlePacket (int client_fd, int length, int packet_id) {
       }
       break;
 
+    case 0x2A:
+      if (state == STATE_PLAY) cs_playerInput(client_fd);
+      break;
+
     case 0x34:
       if (state == STATE_PLAY) cs_setHeldItem(client_fd);
       break;

src/packets.c

@@ -490,13 +490,19 @@ int cs_useItemOn (int client_fd) {
   int sequence = readVarInt(client_fd);
   sc_acknowledgeBlockChange(client_fd, sequence);
 
-  uint8_t target = getBlockAt(x, y, z);
-  if (target == B_crafting_table) {
-    sc_openScreen(client_fd, 12, "Crafting", 8);
-    return 0;
-  } else if (target == B_furnace) {
-    sc_openScreen(client_fd, 14, "Furnace", 7);
-    return 0;
+  PlayerData *player;
+  if (getPlayerData(client_fd, &player)) return 1;
+
+  // Check interaction with containers when not sneaking
+  if (!(player->flags & 0x04)) {
+    uint8_t target = getBlockAt(x, y, z);
+    if (target == B_crafting_table) {
+      sc_openScreen(client_fd, 12, "Crafting", 8);
+      return 0;
+    } else if (target == B_furnace) {
+      sc_openScreen(client_fd, 14, "Furnace", 7);
+      return 0;
+    }
   }
 
   switch (face) {
@@ -509,9 +515,6 @@ int cs_useItemOn (int client_fd) {
     default: break;
   }
 
-  PlayerData *player;
-  if (getPlayerData(client_fd, &player)) return 1;
-
   uint16_t *item = &player->inventory_items[player->hotbar];
   uint8_t *count = &player->inventory_count[player->hotbar];
   uint8_t block = I_to_B(*item);
@@ -1028,6 +1031,21 @@ int sc_removeEntity (int client_fd, int entity_id) {
   return 0;
 }
 
+// C->S Player Input
+int cs_playerInput (int client_fd) {
+
+  uint8_t flags = readByte(client_fd);
+
+  PlayerData *player;
+  if (getPlayerData(client_fd, &player)) return 1;
+
+  // Set or clear sneaking flag
+  if (flags & 0x20) player->flags |= 0x04;
+  else player->flags &= ~0x04;
+
+  return 0;
+}
+
 // S->C Registry Data (multiple packets) and Update Tags (configuration, multiple packets)
 int sc_registries (int client_fd) {