1 files changed, 77 insertions, 0 deletions

diff --git a/src/Items/ItemLadder.h b/src/Items/ItemLadder.h
new file mode 100644
index 000000000..67de799c5
--- /dev/null
+++ b/src/Items/ItemLadder.h
@@ -0,0 +1,77 @@
+
+#pragma once
+
+#include "ItemHandler.h"
+#include "Blocks/BlockLadder.h"
+
+
+
+
+
+class cItemLadderHandler :
+	public cItemHandler
+{
+	using Super = cItemHandler;
+
+public:
+
+	using Super::Super;
+
+private:
+
+	/** Converts the block face of the neighbor to which the ladder is attached to the ladder block's meta. */
+	static NIBBLETYPE BlockFaceToMetaData(eBlockFace a_NeighborBlockFace)
+	{
+		switch (a_NeighborBlockFace)
+		{
+			case BLOCK_FACE_ZM: return 0x2;
+			case BLOCK_FACE_ZP: return 0x3;
+			case BLOCK_FACE_XM: return 0x4;
+			case BLOCK_FACE_XP: return 0x5;
+			case BLOCK_FACE_YM:
+			case BLOCK_FACE_YP: return 0x2;
+			default: UNREACHABLE("Unsupported neighbor block face");
+		}
+	}
+
+
+	virtual bool CommitPlacement(cPlayer & a_Player, const cItem & a_HeldItem, const Vector3i a_PlacePosition, eBlockFace a_ClickedBlockFace, const Vector3i a_CursorPosition) override
+	{
+		const auto & World = *a_Player.GetWorld();
+		const auto ClickedBlockType = World.GetBlock(AddFaceDirection(a_PlacePosition, a_ClickedBlockFace, true));
+
+		// Try finding a suitable neighbor block face for the ladder; start with the given one:
+		if (!cBlockLadderHandler::CanBePlacedOn(ClickedBlockType, a_ClickedBlockFace))
+		{
+			// Couldn't be placed on whatever face was clicked, last ditch resort - find another face:
+			a_ClickedBlockFace = FindSuitableFace(World, a_PlacePosition);
+			if (a_ClickedBlockFace == BLOCK_FACE_NONE)
+			{
+				// No attachable face found - don't place the ladder:
+				return false;
+			}
+		}
+
+		return a_Player.PlaceBlock(a_PlacePosition, E_BLOCK_LADDER, BlockFaceToMetaData(a_ClickedBlockFace));
+	}
+
+
+	/** Returns a suitable neighbor's blockface to place the ladder at the specified position.
+	Returns BLOCK_FACE_NONE on failure. */
+	static eBlockFace FindSuitableFace(const cWorld & a_World, const Vector3i a_Position)
+	{
+		for (const auto Face : { BLOCK_FACE_ZM, BLOCK_FACE_XP, BLOCK_FACE_ZP, BLOCK_FACE_XM })  // Loop through all faces in specific order.
+		{
+			// The direction of Face is relative to the direction the ladder faces.
+			// This is the position, computed inverted, that such a ladder would attach to.
+			const auto NeighborPosition = AddFaceDirection(a_Position, Face, true);
+
+			if (cBlockLadderHandler::CanBePlacedOn(a_World.GetBlock(NeighborPosition), Face))
+			{
+				return Face;
+			}
+		}
+
+		return BLOCK_FACE_NONE;
+	}
+};