fix network overhead in worldgen

src/packets.c

@@ -308,15 +308,8 @@ int sc_chunkDataAndUpdateLight (int client_fd, int _x, int _z) {
     writeByte(client_fd, 8); // bits per entry
     writeVarInt(client_fd, 256);
     for (int j = 0; j < 256; j ++) writeVarInt(client_fd, block_palette[j]);
-    for (int j = 0; j < 4096; j += 8) {
-      for (int k = j + 7; k >= j; k --) {
-        writeByte(client_fd, getBlockAt(
-          k % 16 + x,
-          k / 256 + y,
-          k / 16 % 16 + z
-        ));
-      }
-    }
+    buildChunkSection(x, y, z);
+    send(client_fd, chunk_section, 4096, 0);
     // biome data
     writeByte(client_fd, 0); // bits per entry
     writeByte(client_fd, W_plains); // palette

src/worldgen.c

@@ -141,3 +141,22 @@ skip_tree:
   return B_air;
 
 }
+
+uint8_t chunk_section[4096];
+
+void buildChunkSection (int cx, int cy, int cz) {
+
+  for (int j = 0; j < 4096; j += 8) {
+
+    int y = j / 256 + cy;
+    int z = j / 16 % 16 + cz;
+
+    for (int offset = 7; offset >= 0; offset--) {
+      int k = j + offset;
+      int x = k % 16 + cx;
+      chunk_section[j + 7 - offset] = getBlockAt(x, y, z);
+    }
+
+  }
+
+}

src/worldgen.h

@@ -9,4 +9,7 @@ uint32_t getChunkHash (short x, short z);
 int getHeightAt (int rx, int rz, int _x, int _z, uint32_t chunk_hash);
 uint8_t getBlockAt (int x, int y, int z);
 
+extern uint8_t chunk_section[4096];
+void buildChunkSection (int x, int y, int z);
+
 #endif