Terrain: Fix coordinate parsing (negative coords)

- Optimize readNextUShortsLittleEndian network reading method
- Various coordinate computation issues, negative chunk offsets
- Properly parse negative coordinates for block change events
- Properly reach ground if less than 1 block over the ground

MinecraftClient/Mapping/Chunk.cs

@@ -57,7 +57,7 @@ namespace MinecraftClient.Mapping
         /// <returns>The block</returns>
         public Block GetBlock(Location location)
         {
-            return this[((int)location.X) % Chunk.SizeX, ((int)location.Y) % Chunk.SizeY, ((int)location.Z) % Chunk.SizeZ];
+            return this[location.ChunkBlockX, location.ChunkBlockY, location.ChunkBlockZ];
         }
     }
 }

MinecraftClient/Mapping/Location.cs

@@ -46,6 +46,21 @@ namespace MinecraftClient.Mapping
             Z = z;
         }
 
+        /// <summary>
+        /// Create a new location
+        /// </summary>
+        /// <param name="chunkX">Location of the chunk into the world</param>
+        /// <param name="chunkZ">Location of the chunk into the world</param>
+        /// <param name="blockX">Location of the block into the chunk</param>
+        /// <param name="blockY">Location of the block into the world</param>
+        /// <param name="blockZ">Location of the block into the chunk</param>
+        public Location(int chunkX, int chunkZ, int blockX, int blockY, int blockZ)
+        {
+            X = chunkX * Chunk.SizeX + blockX;
+            Y = blockY;
+            Z = chunkZ * Chunk.SizeZ + blockZ;
+        }
+
         /// <summary>
         /// The X index of the corresponding chunk in the world
         /// </summary>
@@ -53,7 +68,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)X) / Chunk.SizeX;
+                return (int)Math.Floor(X / Chunk.SizeX);
             }
         }
 
@@ -64,7 +79,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)Y) / Chunk.SizeY;
+                return (int)Math.Floor(Y / Chunk.SizeY);
             }
         }
 
@@ -75,7 +90,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)Z) / Chunk.SizeY;
+                return (int)Math.Floor(Z / Chunk.SizeZ);
             }
         }
 
@@ -86,7 +101,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)X) % Chunk.SizeX;
+                return ((int)Math.Floor(X) % Chunk.SizeX + Chunk.SizeX) % Chunk.SizeX;
             }
         }
 
@@ -97,7 +112,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)Y) % Chunk.SizeY;
+                return ((int)Math.Floor(Y) % Chunk.SizeY + Chunk.SizeY) % Chunk.SizeY;
             }
         }
 
@@ -108,7 +123,7 @@ namespace MinecraftClient.Mapping
         {
             get
             {
-                return ((int)Z) % Chunk.SizeZ;
+                return ((int)Math.Floor(Z) % Chunk.SizeZ + Chunk.SizeZ) % Chunk.SizeZ;
             }
         }
 
@@ -153,7 +168,16 @@ namespace MinecraftClient.Mapping
 
         public static Location FromLongRepresentation(ulong location)
         {
-            return new Location(location >> 38, (location >> 26) & 0xFFF, location << 38 >> 38);
+            int x = (int)(location >> 38);
+            int y = (int)((location >> 26) & 0xFFF);
+            int z = (int)(location << 38 >> 38);
+            if (x >= 33554432)
+                x -= 67108864;
+            if (y >= 2048)
+                y -= 4096;
+            if (z >= 33554432)
+                z -= 67108864;
+            return new Location(x, y, z);
         }
 
         /// <summary>

MinecraftClient/McTcpClient.cs

@@ -456,11 +456,15 @@ namespace MinecraftClient
                 {
                     lock (locationLock)
                     {
-                        Location belowMe = location + new Location(0, -1, 0);
-                        Block blockBelowMe = world.GetBlock(belowMe);
-                        handler.SendLocationUpdate(location, blockBelowMe.Solid);
-                        if (!blockBelowMe.Solid)
-                            location = belowMe;
+                        Location onFoots = new Location(location.X, Math.Floor(location.Y), location.Z);
+                        Location belowFoots = location + new Location(0, -1, 0);
+                        Block blockOnFoots = world.GetBlock(onFoots);
+                        Block blockBelowFoots = world.GetBlock(belowFoots);
+                        handler.SendLocationUpdate(location, blockBelowFoots.Solid);
+                        if (!blockBelowFoots.Solid)
+                            location = belowFoots;
+                        else if (!blockOnFoots.Solid)
+                            location = onFoots;
                     }
                     updateTicks = 0;
                 }

MinecraftClient/Protocol/Handlers/Protocol18.cs

@@ -209,7 +209,7 @@ namespace MinecraftClient.Protocol.Handlers
                             int blockZ = locationXZ & 0x0F;
                             int blockY = (ushort)readNextByte(packetData);
                             Block block = new Block((ushort)readNextVarInt(packetData));
-                            handler.GetWorld().SetBlock(new Location(blockX + chunkX * Chunk.SizeX, blockY, blockZ + chunkZ * Chunk.SizeZ), block);
+                            handler.GetWorld().SetBlock(new Location(chunkX, chunkZ, blockX, blockY, blockZ), block);
                         }
                     }
                     break;
@@ -653,16 +653,9 @@ namespace MinecraftClient.Protocol.Handlers
         private static ushort[] readNextUShortsLittleEndian(int amount, List<byte> cache)
         {
             byte[] rawValues = readData(2 * amount, cache);
-            byte[] rawValue = new byte[2];
             ushort[] result = new ushort[amount];
-
             for (int i = 0; i < amount; i++)
-            {
-                rawValue[0] = rawValues[i * 2];
-                rawValue[1] = rawValues[i * 2 + 1];
-                result[i] = BitConverter.ToUInt16(rawValue, 0);
-            }
-
+                result[i] = BitConverter.ToUInt16(rawValues, i * 2);
             return result;
         }