2 files changed, 63 insertions, 32 deletions

diff --git a/src/Blocks/BlockDoor.h b/src/Blocks/BlockDoor.h
index 36dc788aa..ee511a290 100644
--- a/src/Blocks/BlockDoor.h
+++ b/src/Blocks/BlockDoor.h
@@ -96,6 +96,14 @@ public:
 		}
 	}
 
+	/** Returns true iff the door at the specified coords is open.
+	The coords may point to either the top part or the bottom part of the door. */
+	static bool IsOpen(cChunkInterface & a_ChunkInterface, const Vector3i a_BlockPos)
+	{
+		const auto Meta = GetCompleteDoorMeta(a_ChunkInterface, a_BlockPos);
+		return (Meta & 0x04) != 0;
+	}
+
 	/** Sets the door to the specified state. If the door is already in that state, does nothing. */
 	static void SetOpen(cChunkInterface & a_ChunkInterface, const Vector3i a_BlockPos, bool a_Open)
 	{
@@ -237,18 +245,6 @@ private:
 
 
 
-	/** Returns true iff the door at the specified coords is open.
-	The coords may point to either the top part or the bottom part of the door. */
-	static NIBBLETYPE IsOpen(cChunkInterface & a_ChunkInterface, const Vector3i a_BlockPos)
-	{
-		NIBBLETYPE Meta = GetCompleteDoorMeta(a_ChunkInterface, a_BlockPos);
-		return ((Meta & 0x04) != 0);
-	}
-
-
-
-
-
 	/** Returns the complete meta composed from the both parts of the door as (TopMeta << 4) | BottomMeta
 	The coords may point to either part of the door.
 	The returned value has bit 3 (0x08) set iff the coords point to the top part of the door.
diff --git a/src/Simulator/IncrementalRedstoneSimulator/DoorHandler.h b/src/Simulator/IncrementalRedstoneSimulator/DoorHandler.h
index fa5debbbf..00fd8c7eb 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/DoorHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/DoorHandler.h
@@ -22,42 +22,77 @@ namespace DoorHandler
 		return 0;
 	}
 
+	inline void ForValidSourcePositions(const cChunk & a_Chunk, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, ForEachSourceCallback & Callback)
+	{
+		UNUSED(a_Chunk);
+		UNUSED(a_BlockType);
+		UNUSED(a_Meta);
+		InvokeForAdjustedRelatives(Callback, a_Position, RelativeAdjacents);
+	}
+
 	inline void Update(cChunk & a_Chunk, cChunk &, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, PowerLevel Power)
 	{
 		// LOGD("Evaluating dori the door (%d %d %d)", a_Position.x, a_Position.y, a_Position.z);
 
-		if ((a_Meta & 0x8) == 0x8)
+		NIBBLETYPE TopMeta;
+		const bool IsTop = (a_Meta & 0x8) == 0x8;
+		const auto TopPosition = IsTop ? a_Position : a_Position.addedY(1);
+
+		// Figure out the metadata of the top half, which stores the previous redstone power state:
+		if (IsTop)
 		{
-			// We're treating the bottom half as the source of truth, so ignore updates to the top:
-			return;
+			TopMeta = a_Meta;
+		}
+		else
+		{
+			if (TopPosition.y == cChunkDef::Height)
+			{
+				return;
+			}
+
+			BLOCKTYPE AboveType;
+			a_Chunk.GetBlockTypeMeta(TopPosition, AboveType, TopMeta);
+			if (!cBlockDoorHandler::IsDoorBlockType(AboveType))
+			{
+				return;
+			}
 		}
 
-		const auto TopPosition = a_Position + OffsetYP;
-		ForEachSourceCallback Callback(a_Chunk, TopPosition, a_BlockType);
-		RedstoneHandler::ForValidSourcePositions(a_Chunk, TopPosition, a_BlockType, a_Meta, Callback);
+		const auto OppositeHalfPosition = a_Position + (IsTop ? OffsetYM : OffsetYP);
+		ForEachSourceCallback Callback(a_Chunk, OppositeHalfPosition, a_BlockType);
+		ForValidSourcePositions(a_Chunk, OppositeHalfPosition, a_BlockType, a_Meta, Callback);
 
-		// Factor in what the upper half is getting:
+		// Factor in what the other half is getting:
 		Power = std::max(Power, Callback.Power);
 
-		cChunkInterface ChunkInterface(a_Chunk.GetWorld()->GetChunkMap());
-		// Use redstone data rather than block state so players can override redstone control
-		const auto Previous = DataForChunk(a_Chunk).ExchangeUpdateOncePowerData(a_Position, Power);
-		const bool IsOpen = (Previous != 0);
 		const bool ShouldBeOpen = Power != 0;
+		const bool PreviouslyPowered = (TopMeta & 0x2) == 0x2;
+
+		// Allow players to override redstone control
+		// don't update if redstone power hasn't changed since we last saw it:
+		if (ShouldBeOpen == PreviouslyPowered)
+		{
+			return;
+		}
+
+		// Update the previous redstone power:
+		if (ShouldBeOpen)
+		{
+			a_Chunk.SetMeta(TopPosition, TopMeta | 0x2);
+		}
+		else
+		{
+			a_Chunk.SetMeta(TopPosition, TopMeta & ~0x2);
+		}
+
+		cChunkInterface ChunkInterface(a_Chunk.GetWorld()->GetChunkMap());
 		const auto AbsolutePosition = cChunkDef::RelativeToAbsolute(a_Position, a_Chunk.GetPos());
 
-		if (ShouldBeOpen != IsOpen)
+		// Toggle the door, if it needs to be changed:
+		if (ShouldBeOpen != cBlockDoorHandler::IsOpen(ChunkInterface, AbsolutePosition))
 		{
 			cBlockDoorHandler::SetOpen(ChunkInterface, AbsolutePosition, ShouldBeOpen);
 			a_Chunk.GetWorld()->BroadcastSoundParticleEffect(EffectID::SFX_RANDOM_WOODEN_DOOR_OPEN, AbsolutePosition, 0);
 		}
 	}
-
-	inline void ForValidSourcePositions(const cChunk & a_Chunk, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, ForEachSourceCallback & Callback)
-	{
-		UNUSED(a_Chunk);
-		UNUSED(a_BlockType);
-		UNUSED(a_Meta);
-		InvokeForAdjustedRelatives(Callback, a_Position, RelativeAdjacents);
-	}
 };