From aa74a55a1938f4dfffb2aa85cce36e4b3ed1d1f6 Mon Sep 17 00:00:00 2001
From: p2r3 <p2r3@p2r3.com>
Date: Sat, 23 Aug 2025 23:04:45 +0300
Subject: [PATCH] implement growing saplings with bone meal

---
 include/structures.h |  6 +++++
 src/procedures.c     | 52 +++++++++++++++++++++++++++++------------
 src/structures.c     | 55 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+), 15 deletions(-)
 create mode 100644 include/structures.h
 create mode 100644 src/structures.c

diff --git a/include/structures.h b/include/structures.h
new file mode 100644
index 0000000..8eca4eb
--- /dev/null
+++ b/include/structures.h
@@ -0,0 +1,6 @@
+#ifndef H_STRUCTURES
+#define H_STRUCTURES
+
+void placeTreeStructure (short x, uint8_t y, short z);
+
+#endif
diff --git a/src/procedures.c b/src/procedures.c
index 5cc87fd..008cb04 100644
--- a/src/procedures.c
+++ b/src/procedures.c
@@ -7,6 +7,8 @@
 #include "packets.h"
 #include "registries.h"
 #include "worldgen.h"
+#include "structures.h"
+#include "procedures.h"
 
 int client_states[MAX_PLAYERS * 2];
 
@@ -573,6 +575,35 @@ void handlePlayerUseItem (PlayerData *player, short x, short y, short z, uint8_t
     }
   }
 
+  // If the selected slot doesn't hold any items, exit
+  uint8_t *count = &player->inventory_count[player->hotbar];
+  if (*count == 0) return;
+
+  // Check special item handling
+  uint16_t *item = &player->inventory_items[player->hotbar];
+  if (*item == I_bone_meal) {
+    uint8_t target = getBlockAt(x, y, z);
+    uint8_t target_below = getBlockAt(x, y - 1, z);
+    if (target == B_oak_sapling) {
+      // Consume the bone meal (yes, even before checks)
+      // Wasting bone meal on misplanted saplings is vanilla behavior
+      if ((*count -= 1) == 0) item = 0;
+      sc_setContainerSlot(player->client_fd, 0, serverSlotToClientSlot(0, player->hotbar), *count, *item);
+      if ( // Saplings can only grow when placed on these blocks
+        target_below == B_dirt ||
+        target_below == B_grass_block ||
+        target_below == B_snowy_grass_block
+      ) {
+        // Bone meal has a 25% chance of growing a tree from a sapling
+        if ((fast_rand() & 3) == 0) placeTreeStructure(x, y, z);
+      }
+    }
+  }
+
+  // If the selected item doesn't correspond to a block, exit
+  uint8_t block = I_to_B(*item);
+  if (block == 0) return;
+
   switch (face) {
     case 0: y -= 1; break;
     case 1: y += 1; break;
@@ -583,18 +614,9 @@ void handlePlayerUseItem (PlayerData *player, short x, short y, short z, uint8_t
     default: break;
   }
 
-  uint16_t *item = &player->inventory_items[player->hotbar];
-  uint8_t *count = &player->inventory_count[player->hotbar];
-  uint8_t block = I_to_B(*item);
-
-  // if the selected item doesn't correspond to a block, exit
-  if (block == 0) return;
-  // if the selected slot doesn't hold any items, exit
-  if (*count == 0) return;
-
-  // check if the block's placement conditions are met
+  // Check if the block's placement conditions are met
   if (
-    !( // player is not in the way
+    !( // Is player in the way?
       !isPassableBlock(block) &&
       x == player->x &&
       (y == player->y || y == player->y + 1) &&
@@ -603,15 +625,15 @@ void handlePlayerUseItem (PlayerData *player, short x, short y, short z, uint8_t
     isReplaceableBlock(getBlockAt(x, y, z)) &&
     (!isColumnBlock(block) || getBlockAt(x, y - 1, z) != B_air)
   ) {
-    // decrease item amount in selected slot
+    // Decrease item amount in selected slot
     *count -= 1;
-    // clear item id in slot if amount is zero
+    // Clear item id in slot if amount is zero
     if (*count == 0) *item = 0;
-    // apply server-side block change
+    // Apply server-side block change
     makeBlockChange(x, y, z, block);
   }
 
-  // sync hotbar contents to player
+  // Sync hotbar contents to player
   sc_setContainerSlot(player->client_fd, 0, serverSlotToClientSlot(0, player->hotbar), *count, *item);
 
 }
diff --git a/src/structures.c b/src/structures.c
new file mode 100644
index 0000000..348a7cb
--- /dev/null
+++ b/src/structures.c
@@ -0,0 +1,55 @@
+#include <stdlib.h>
+
+#include "globals.h"
+#include "tools.h"
+#include "registries.h"
+#include "worldgen.h"
+#include "procedures.h"
+#include "structures.h"
+
+void setBlockIfReplaceable (short x, uint8_t y, short z, uint8_t block) {
+  if (!isReplaceableBlock(getBlockAt(x, y, z))) return;
+  makeBlockChange(x, y, z, block);
+}
+
+// Places a tree centered on the input coordinates
+void placeTreeStructure (short x, uint8_t y, short z) {
+
+  // Get a random number for tree height and leaf edges
+  uint32_t r = fast_rand();
+  uint8_t height = 4 + (r % 3);
+
+  // Set tree base - replace sapling with log and put dirt below
+  makeBlockChange(x, y - 1, z, B_dirt);
+  makeBlockChange(x, y, z, B_oak_log);
+  // Create tree stump
+  for (int i = 1; i < height; i ++) {
+    setBlockIfReplaceable(x, y + i, z, B_oak_log);
+  }
+  // Keep track of leaf corners, determines random number bit shift
+  uint8_t t = 2;
+  // First (bottom) leaf layer
+  for (int i = -2; i <= 2; i ++) {
+    for (int j = -2; j <= 2; j ++) {
+      setBlockIfReplaceable(x + i, y + height - 3, z + j, B_oak_leaves);
+      // Randomly skip some corners, emulating vanilla tree shape
+      if ((i == 2 || i == -2) && (j == 2 || j == -2)) {
+        t ++;
+        if ((r >> t) & 1) continue;
+      }
+      setBlockIfReplaceable(x + i, y + height - 2, z + j, B_oak_leaves);
+    }
+  }
+  // Second (top) leaf layer
+  for (int i = -1; i <= 1; i ++) {
+    for (int j = -1; j <= 1; j ++) {
+      setBlockIfReplaceable(x + i, y + height - 1, z + j, B_oak_leaves);
+      if ((i == 1 || i == -1) && (j == 1 || j == -1)) {
+        t ++;
+        if ((r >> t) & 1) continue;
+      }
+      setBlockIfReplaceable(x + i, y + height, z + j, B_oak_leaves);
+    }
+  }
+
+}