5 files changed, 135 insertions, 0 deletions

diff --git a/src/Blocks/BlockObserver.h b/src/Blocks/BlockObserver.h
index 30c19ba2e..78a4c05b2 100644
--- a/src/Blocks/BlockObserver.h
+++ b/src/Blocks/BlockObserver.h
@@ -16,4 +16,27 @@ public:
 	{
 	}
 
+	inline static Vector3i GetObservingFaceOffset(NIBBLETYPE a_Meta)
+	{
+		return -GetSignalOutputOffset(a_Meta);
+	}
+
+	inline static Vector3i GetSignalOutputOffset(NIBBLETYPE a_Meta)
+	{
+		switch (a_Meta & 0x7)
+		{
+			case 0x00: return { 0, 1, 0 };
+			case 0x01: return { 0, -1, 0 };
+			case 0x02: return { 0, 0, 1 };
+			case 0x03: return { 0, 0, -1 };
+			case 0x04: return { 1, 0, 0 };
+			case 0x05: return { -1, 0, 0 };
+			default:
+			{
+				LOGWARNING("%s: Unknown metadata: %d", __FUNCTION__, a_Meta);
+				ASSERT(!"Unknown metadata while determining orientation of observer!");
+				return { 0, 0, 0 };
+			}
+		}
+	}
 };
diff --git a/src/Simulator/IncrementalRedstoneSimulator/CMakeLists.txt b/src/Simulator/IncrementalRedstoneSimulator/CMakeLists.txt
index fada3e662..0c2346322 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/CMakeLists.txt
+++ b/src/Simulator/IncrementalRedstoneSimulator/CMakeLists.txt
@@ -22,6 +22,7 @@ set (HDRS
 	PistonHandler.h
 	SmallGateHandler.h
 	NoteBlockHandler.h
+	ObserverHandler.h
 	TNTHandler.h
 	TrappedChestHandler.h
 	TripwireHookHandler.h
diff --git a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.cpp b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.cpp
index 6be03c947..4e20c9407 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.cpp
+++ b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.cpp
@@ -18,6 +18,7 @@
 #include "PistonHandler.h"
 #include "SmallGateHandler.h"
 #include "NoteBlockHandler.h"
+#include "ObserverHandler.h"
 #include "TNTHandler.h"
 #include "PoweredRailHandler.h"
 #include "PressurePlateHandler.h"
@@ -90,6 +91,8 @@ std::unique_ptr<cRedstoneHandler> cIncrementalRedstoneSimulator::CreateComponent
 		case E_BLOCK_REDSTONE_TORCH_OFF:
 		case E_BLOCK_REDSTONE_TORCH_ON: return cpp14::make_unique<cRedstoneTorchHandler>();
 
+		case E_BLOCK_OBSERVER: return cpp14::make_unique<cObserverHandler>();
+
 		case E_BLOCK_PISTON:
 		case E_BLOCK_STICKY_PISTON: return cpp14::make_unique<cPistonHandler>();
 
diff --git a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
index 4ef9801a3..8213eddae 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
@@ -61,6 +61,7 @@ public:
 			case E_BLOCK_JUNGLE_DOOR:
 			case E_BLOCK_JUNGLE_FENCE_GATE:
 			case E_BLOCK_NOTE_BLOCK:
+			case E_BLOCK_OBSERVER:
 			case E_BLOCK_PISTON:
 			case E_BLOCK_POWERED_RAIL:
 			case E_BLOCK_REDSTONE_LAMP_OFF:
@@ -127,6 +128,7 @@ public:
 			case E_BLOCK_LEVER:
 			case E_BLOCK_LIGHT_WEIGHTED_PRESSURE_PLATE:
 			case E_BLOCK_NOTE_BLOCK:
+			case E_BLOCK_OBSERVER:
 			case E_BLOCK_POWERED_RAIL:
 			case E_BLOCK_REDSTONE_LAMP_OFF:
 			case E_BLOCK_REDSTONE_LAMP_ON:
diff --git a/src/Simulator/IncrementalRedstoneSimulator/ObserverHandler.h b/src/Simulator/IncrementalRedstoneSimulator/ObserverHandler.h
new file mode 100644
index 000000000..cb5bc74fc
--- /dev/null
+++ b/src/Simulator/IncrementalRedstoneSimulator/ObserverHandler.h
@@ -0,0 +1,106 @@
+
+#pragma once
+
+#include "RedstoneHandler.h"
+#include "../../Blocks/BlockObserver.h"
+
+
+
+
+
+class cObserverHandler : public cRedstoneHandler
+{
+public:
+
+	inline static bool IsOn(NIBBLETYPE a_Meta)
+	{
+		return (a_Meta & 0x8) == 0x8;
+	}
+
+	static bool ShouldPowerOn(cWorld & a_World, const Vector3i a_Position, NIBBLETYPE a_Meta, cIncrementalRedstoneSimulatorChunkData * a_Data)
+	{
+		BLOCKTYPE BlockType;
+		NIBBLETYPE BlockMeta;
+		if (!a_World.GetBlockTypeMeta(a_Position + cBlockObserverHandler::GetObservingFaceOffset(a_Meta), BlockType, BlockMeta))
+		{
+			return false;
+		}
+
+		// Cache the last seen block type and meta in the power data for this position
+		auto Observed = PoweringData(BlockType, BlockMeta);
+		auto Previous = a_Data->ExchangeUpdateOncePowerData(a_Position, Observed);
+
+		// Determine if to signal an update based on the block previously observed changed
+		return (Previous.PoweringBlock != Observed.PoweringBlock) || (Previous.PowerLevel != Observed.PowerLevel);
+	}
+
+	virtual unsigned char GetPowerDeliveredToPosition(cWorld & a_World, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, Vector3i a_QueryPosition, BLOCKTYPE a_QueryBlockType) const override
+	{
+		if (IsOn(a_Meta) && (a_QueryPosition == (a_Position + cBlockObserverHandler::GetSignalOutputOffset(a_Meta))))
+		{
+			return 15;
+		}
+
+		return 0;
+	}
+
+	virtual unsigned char GetPowerLevel(cWorld & a_World, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta) const override
+	{
+		return IsOn(a_BlockType) ? 15 : 0;
+	}
+
+	virtual cVector3iArray Update(cWorld & a_World, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, PoweringData a_PoweringData) const override
+	{
+		// LOGD("Evaluating Lenny the observer (%i %i %i)", a_Position.x, a_Position.y, a_Position.z);
+
+		auto Data = static_cast<cIncrementalRedstoneSimulator *>(a_World.GetRedstoneSimulator())->GetChunkData();
+		auto DelayInfo = Data->GetMechanismDelayInfo(a_Position);
+
+		if (DelayInfo == nullptr)
+		{
+			if (!ShouldPowerOn(a_World, a_Position, a_Meta, Data))
+			{
+				return {};
+			}
+
+			// From rest, we've determined there was a block update
+			// Schedule power-on 1 tick in the future
+			Data->m_MechanismDelays[a_Position] = std::make_pair(1, true);
+
+			return {};
+		}
+
+		int DelayTicks;
+		bool ShouldPowerOn;
+		std::tie(DelayTicks, ShouldPowerOn) = *DelayInfo;
+
+		if (DelayTicks != 0)
+		{
+			return {};
+		}
+
+		if (ShouldPowerOn)
+		{
+			// Remain on for 1 tick before resetting
+			*DelayInfo = std::make_pair(1, false);
+			a_World.SetBlockMeta(a_Position.x, a_Position.y, a_Position.z, a_Meta | 0x8, a_Meta);
+		}
+		else
+		{
+			// We've reset. Erase delay data in preparation for detecting further updates
+			Data->m_MechanismDelays.erase(a_Position);
+			a_World.SetBlockMeta(a_Position.x, a_Position.y, a_Position.z, a_Meta & ~0x8, a_Meta);
+		}
+
+		return { a_Position + cBlockObserverHandler::GetSignalOutputOffset(a_Meta) };
+	}
+
+	virtual cVector3iArray GetValidSourcePositions(cWorld & a_World, Vector3i a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta) const override
+	{
+		UNUSED(a_World);
+		UNUSED(a_Position);
+		UNUSED(a_BlockType);
+		UNUSED(a_BlockType);
+		return {};
+	}
+};