1 files changed, 93 insertions, 0 deletions

diff --git a/src/Items/ItemSlab.h b/src/Items/ItemSlab.h
new file mode 100644
index 000000000..1b68b9d0c
--- /dev/null
+++ b/src/Items/ItemSlab.h
@@ -0,0 +1,93 @@
+
+// ItemSlab.h
+
+// Declares the cItemSlabHandler responsible for handling slabs, when in their item form.
+
+
+
+
+
+#pragma once
+
+#include "ItemHandler.h"
+#include "../Blocks/BlockSlab.h"
+
+
+
+
+
+class cItemSlabHandler:
+	public cItemHandler
+{
+	typedef cItemHandler super;
+
+public:
+
+	/** Creates a new handler for the specified slab item type.
+	Sets the handler to use the specified doubleslab block type for combining self into doubleslabs. */
+	cItemSlabHandler(int a_ItemType, BLOCKTYPE a_DoubleSlabBlockType):
+		super(a_ItemType),
+		m_DoubleSlabBlockType(a_DoubleSlabBlockType)
+	{
+	}
+
+
+	// cItemHandler overrides:
+	virtual bool OnPlayerPlace(
+		cWorld & a_World, cPlayer & a_Player, const cItem & a_EquippedItem,
+		int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace,
+		int a_CursorX, int a_CursorY, int a_CursorZ
+	) override
+	{
+		// Special slab handling - placing a slab onto another slab produces a dblslab instead:
+		BLOCKTYPE ClickedBlockType;
+		NIBBLETYPE ClickedBlockMeta;
+		a_World.GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, ClickedBlockType, ClickedBlockMeta);
+		if (
+			(ClickedBlockType == m_ItemType) &&                // Placing the same slab material
+			(ClickedBlockMeta == a_EquippedItem.m_ItemDamage)  // Placing the same slab sub-kind (and existing slab is single)
+		)
+		{
+			// If clicking the top side of a bottom-half slab, combine into a doubleslab:
+			if (
+				(a_BlockFace == BLOCK_FACE_TOP) &&
+				((ClickedBlockMeta & 0x08) == 0)
+			)
+			{
+				return a_Player.PlaceBlock(a_BlockX, a_BlockY, a_BlockZ, m_DoubleSlabBlockType, ClickedBlockMeta & 0x07);
+			}
+
+			// If clicking the bottom side of a top-half slab, combine into a doubleslab:
+			if (
+				(a_BlockFace == BLOCK_FACE_BOTTOM) &&
+				((ClickedBlockMeta & 0x08) != 0)
+			)
+			{
+				return a_Player.PlaceBlock(a_BlockX, a_BlockY, a_BlockZ, m_DoubleSlabBlockType, ClickedBlockMeta & 0x07);
+			}
+		}
+
+		// The slabs didn't combine, use the default handler to place the slab:
+		bool res = super::OnPlayerPlace(a_World, a_Player, a_EquippedItem, a_BlockX, a_BlockY, a_BlockZ, a_BlockFace, a_CursorX, a_CursorY, a_CursorZ);
+
+		/*
+		The client has a bug when a slab replaces snow and there's a slab above it.
+		The client then combines the slab above, rather than replacing the snow.
+		We send the block above the currently placed block back to the client to fix the bug.
+		Ref.: http://forum.mc-server.org/showthread.php?tid=434&pid=17388#pid17388
+		*/
+		if ((a_BlockFace == BLOCK_FACE_TOP) && (a_BlockY < cChunkDef::Height - 1))
+		{
+			a_Player.SendBlocksAround(a_BlockX, a_BlockY + 1, a_BlockZ, 1);
+		}
+		return res;
+	}
+
+protected:
+	/** The block type to use when the slab combines into a doubleslab block. */
+	BLOCKTYPE m_DoubleSlabBlockType;
+};
+
+
+
+