17 files changed, 59 insertions, 64 deletions

diff --git a/src/Simulator/DelayedFluidSimulator.cpp b/src/Simulator/DelayedFluidSimulator.cpp
index d21e8dc6d..c3e262dec 100644
--- a/src/Simulator/DelayedFluidSimulator.cpp
+++ b/src/Simulator/DelayedFluidSimulator.cpp
@@ -78,9 +78,9 @@ cDelayedFluidSimulator::cDelayedFluidSimulator(cWorld & a_World, BLOCKTYPE a_Flu
 
 
 
-void cDelayedFluidSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cDelayedFluidSimulator::AddBlock(Vector3i a_Block, cChunk * a_Chunk)
 {
-	if ((a_BlockY < 0) || (a_BlockY >= cChunkDef::Height))
+	if ((a_Block.y < 0) || (a_Block.y >= cChunkDef::Height))
 	{
 		// Not inside the world (may happen when rclk with a full bucket - the client sends Y = -1)
 		return;
@@ -91,9 +91,9 @@ void cDelayedFluidSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ,
 		return;
 	}
 
-	int RelX = a_BlockX - a_Chunk->GetPosX() * cChunkDef::Width;
-	int RelZ = a_BlockZ - a_Chunk->GetPosZ() * cChunkDef::Width;
-	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_BlockY, RelZ);
+	int RelX = a_Block.x - a_Chunk->GetPosX() * cChunkDef::Width;
+	int RelZ = a_Block.z - a_Chunk->GetPosZ() * cChunkDef::Width;
+	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_Block.y, RelZ);
 	if (BlockType != m_FluidBlock)
 	{
 		return;
@@ -104,7 +104,7 @@ void cDelayedFluidSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ,
 	cDelayedFluidSimulatorChunkData::cSlot & Slot = ChunkData->m_Slots[m_AddSlotNum];
 
 	// Add, if not already present:
-	if (!Slot.Add(RelX, a_BlockY, RelZ))
+	if (!Slot.Add(RelX, a_Block.y, RelZ))
 	{
 		return;
 	}
diff --git a/src/Simulator/DelayedFluidSimulator.h b/src/Simulator/DelayedFluidSimulator.h
index 62efb717e..78619a608 100644
--- a/src/Simulator/DelayedFluidSimulator.h
+++ b/src/Simulator/DelayedFluidSimulator.h
@@ -54,7 +54,7 @@ public:
 	cDelayedFluidSimulator(cWorld & a_World, BLOCKTYPE a_Fluid, BLOCKTYPE a_StationaryFluid, int a_TickDelay);
 
 	// cSimulator overrides:
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override;
 	virtual void Simulate(float a_Dt) override;
 	virtual void SimulateChunk(std::chrono::milliseconds a_Dt, int a_ChunkX, int a_ChunkZ, cChunk * a_Chunk) override;
 	virtual cFluidSimulatorData * CreateChunkData(void) override { return new cDelayedFluidSimulatorChunkData(m_TickDelay); }
diff --git a/src/Simulator/FireSimulator.cpp b/src/Simulator/FireSimulator.cpp
index 55dd7008b..45969bd0a 100644
--- a/src/Simulator/FireSimulator.cpp
+++ b/src/Simulator/FireSimulator.cpp
@@ -218,16 +218,16 @@ bool cFireSimulator::DoesBurnForever(BLOCKTYPE a_BlockType)
 
 
 
-void cFireSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cFireSimulator::AddBlock(Vector3i a_Block, cChunk * a_Chunk)
 {
 	if ((a_Chunk == nullptr) || !a_Chunk->IsValid())
 	{
 		return;
 	}
 
-	int RelX = a_BlockX - a_Chunk->GetPosX() * cChunkDef::Width;
-	int RelZ = a_BlockZ - a_Chunk->GetPosZ() * cChunkDef::Width;
-	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_BlockY, RelZ);
+	int RelX = a_Block.x - a_Chunk->GetPosX() * cChunkDef::Width;
+	int RelZ = a_Block.z - a_Chunk->GetPosZ() * cChunkDef::Width;
+	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_Block.y, RelZ);
 	if (!IsAllowedBlock(BlockType))
 	{
 		return;
@@ -237,15 +237,15 @@ void cFireSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk *
 	cFireSimulatorChunkData & ChunkData = a_Chunk->GetFireSimulatorData();
 	for (cCoordWithIntList::iterator itr = ChunkData.begin(), end = ChunkData.end(); itr != end; ++itr)
 	{
-		if ((itr->x == RelX) && (itr->y == a_BlockY) && (itr->z == RelZ))
+		if ((itr->x == RelX) && (itr->y == a_Block.y) && (itr->z == RelZ))
 		{
 			// Already present, skip adding
 			return;
 		}
 	}  // for itr - ChunkData[]
 
-	FLOG("FS: Adding block {%d, %d, %d}", a_BlockX, a_BlockY, a_BlockZ);
-	ChunkData.push_back(cCoordWithInt(RelX, a_BlockY, RelZ, 100));
+	FLOG("FS: Adding block {%d, %d, %d}", a_Block.x, a_Block.y, a_Block.z);
+	ChunkData.push_back(cCoordWithInt(RelX, a_Block.y, RelZ, 100));
 }
 
 
diff --git a/src/Simulator/FireSimulator.h b/src/Simulator/FireSimulator.h
index 5c926e6ea..bbfeb045e 100644
--- a/src/Simulator/FireSimulator.h
+++ b/src/Simulator/FireSimulator.h
@@ -43,7 +43,7 @@ protected:
 	int m_ReplaceFuelChance;
 
 
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override;
 
 	/** Returns the time [msec] after which the specified fire block is stepped again; based on surrounding fuels */
 	int GetBurnStepTime(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ);
diff --git a/src/Simulator/FloodyFluidSimulator.cpp b/src/Simulator/FloodyFluidSimulator.cpp
index 8d712824f..d24b6aa9b 100644
--- a/src/Simulator/FloodyFluidSimulator.cpp
+++ b/src/Simulator/FloodyFluidSimulator.cpp
@@ -325,7 +325,7 @@ void cFloodyFluidSimulator::SpreadToNeighbor(cChunk * a_NearChunk, int a_RelX, i
 	// Spread:
 	FLOG("  Spreading to {%d, %d, %d} with meta %d", BlockX, a_RelY, BlockZ, a_NewMeta);
 	a_NearChunk->SetBlock(a_RelX, a_RelY, a_RelZ, m_FluidBlock, a_NewMeta);
-	m_World.GetSimulatorManager()->WakeUp(BlockX, a_RelY, BlockZ, a_NearChunk);
+	m_World.GetSimulatorManager()->WakeUp({BlockX, a_RelY, BlockZ}, a_NearChunk);
 
 	HardenBlock(a_NearChunk, a_RelX, a_RelY, a_RelZ, m_FluidBlock, a_NewMeta);
 }
diff --git a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
index a869b3489..e00db39b5 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/IncrementalRedstoneSimulator.h
@@ -31,9 +31,9 @@ public:
 		return IsRedstone(a_BlockType);
 	}
 
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override
 	{
-		m_Data.WakeUp({ a_BlockX, a_BlockY, a_BlockZ });
+		m_Data.WakeUp(a_Block);
 	}
 
 	/** Returns if a block is a mechanism (something that accepts power and does something)
diff --git a/src/Simulator/NoopFluidSimulator.h b/src/Simulator/NoopFluidSimulator.h
index a237e960b..11bbf061d 100644
--- a/src/Simulator/NoopFluidSimulator.h
+++ b/src/Simulator/NoopFluidSimulator.h
@@ -27,11 +27,9 @@ public:
 	}
 
 	// cSimulator overrides:
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override
 	{
-		UNUSED(a_BlockX);
-		UNUSED(a_BlockY);
-		UNUSED(a_BlockZ);
+		UNUSED(a_Block);
 		UNUSED(a_Chunk);
 	}
 	virtual void Simulate(float a_Dt) override { UNUSED(a_Dt);}
diff --git a/src/Simulator/NoopRedstoneSimulator.h b/src/Simulator/NoopRedstoneSimulator.h
index a5d9e9448..d9e8e00f5 100644
--- a/src/Simulator/NoopRedstoneSimulator.h
+++ b/src/Simulator/NoopRedstoneSimulator.h
@@ -27,11 +27,9 @@ public:
 		UNUSED(a_Chunk);
 	}
 	virtual bool IsAllowedBlock( BLOCKTYPE a_BlockType) override { return false; }
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override
 	{
-		UNUSED(a_BlockX);
-		UNUSED(a_BlockY);
-		UNUSED(a_BlockZ);
+		UNUSED(a_Block);
 		UNUSED(a_Chunk);
 	}
 
diff --git a/src/Simulator/RedstoneSimulator.h b/src/Simulator/RedstoneSimulator.h
index cee43db60..2f6b32398 100644
--- a/src/Simulator/RedstoneSimulator.h
+++ b/src/Simulator/RedstoneSimulator.h
@@ -33,7 +33,7 @@ public:
 	virtual void Simulate(float a_Dt) = 0;
 	virtual void SimulateChunk(std::chrono::milliseconds a_Dt, int a_ChunkX, int a_ChunkZ, cChunk * a_Chunk) = 0;
 	virtual bool IsAllowedBlock(BLOCKTYPE a_BlockType) = 0;
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) = 0;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) = 0;
 
 	virtual cRedstoneSimulatorChunkData * CreateChunkData() = 0;
 
diff --git a/src/Simulator/SandSimulator.cpp b/src/Simulator/SandSimulator.cpp
index 6b1219edb..c26452d98 100644
--- a/src/Simulator/SandSimulator.cpp
+++ b/src/Simulator/SandSimulator.cpp
@@ -101,15 +101,15 @@ bool cSandSimulator::IsAllowedBlock(BLOCKTYPE a_BlockType)
 
 
 
-void cSandSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cSandSimulator::AddBlock(Vector3i a_Block, cChunk * a_Chunk)
 {
 	if ((a_Chunk == nullptr) || !a_Chunk->IsValid())
 	{
 		return;
 	}
-	int RelX = a_BlockX - a_Chunk->GetPosX() * cChunkDef::Width;
-	int RelZ = a_BlockZ - a_Chunk->GetPosZ() * cChunkDef::Width;
-	if (!IsAllowedBlock(a_Chunk->GetBlock(RelX, a_BlockY, RelZ)))
+	int RelX = a_Block.x - a_Chunk->GetPosX() * cChunkDef::Width;
+	int RelZ = a_Block.z - a_Chunk->GetPosZ() * cChunkDef::Width;
+	if (!IsAllowedBlock(a_Chunk->GetBlock(RelX, a_Block.y, RelZ)))
 	{
 		return;
 	}
@@ -118,14 +118,14 @@ void cSandSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk *
 	cSandSimulatorChunkData & ChunkData = a_Chunk->GetSandSimulatorData();
 	for (cSandSimulatorChunkData::iterator itr = ChunkData.begin(); itr != ChunkData.end(); ++itr)
 	{
-		if ((itr->x == RelX) && (itr->y == a_BlockY) && (itr->z == RelZ))
+		if ((itr->x == RelX) && (itr->y == a_Block.y) && (itr->z == RelZ))
 		{
 			return;
 		}
 	}
 
 	m_TotalBlocks += 1;
-	ChunkData.push_back(cCoordWithInt(RelX, a_BlockY, RelZ));
+	ChunkData.push_back(cCoordWithInt(RelX, a_Block.y, RelZ));
 }
 
 
diff --git a/src/Simulator/SandSimulator.h b/src/Simulator/SandSimulator.h
index cda26775e..cee0a85e6 100644
--- a/src/Simulator/SandSimulator.h
+++ b/src/Simulator/SandSimulator.h
@@ -59,7 +59,7 @@ protected:
 
 	int  m_TotalBlocks;    // Total number of blocks currently in the queue for simulating
 
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override;
 
 	/** Performs the instant fall of the block - removes it from top, Finishes it at the bottom */
 	void DoInstantFall(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ);
diff --git a/src/Simulator/Simulator.cpp b/src/Simulator/Simulator.cpp
index 7d3ce7851..9dbdd6a07 100644
--- a/src/Simulator/Simulator.cpp
+++ b/src/Simulator/Simulator.cpp
@@ -18,20 +18,20 @@
 
 
 
-void cSimulator::WakeUp(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cSimulator::WakeUp(Vector3i a_Block, cChunk * a_Chunk)
 {
-	AddBlock(a_BlockX, a_BlockY, a_BlockZ, a_Chunk);
-	AddBlock(a_BlockX - 1, a_BlockY, a_BlockZ, a_Chunk->GetNeighborChunk(a_BlockX - 1, a_BlockZ));
-	AddBlock(a_BlockX + 1, a_BlockY, a_BlockZ, a_Chunk->GetNeighborChunk(a_BlockX + 1, a_BlockZ));
-	AddBlock(a_BlockX, a_BlockY, a_BlockZ - 1, a_Chunk->GetNeighborChunk(a_BlockX, a_BlockZ - 1));
-	AddBlock(a_BlockX, a_BlockY, a_BlockZ + 1, a_Chunk->GetNeighborChunk(a_BlockX, a_BlockZ + 1));
-	if (a_BlockY > 0)
+	AddBlock(a_Block, a_Chunk);
+	AddBlock(a_Block + Vector3i(-1, 0, 0), a_Chunk->GetNeighborChunk(a_Block.x - 1, a_Block.z));
+	AddBlock(a_Block + Vector3i( 1, 0, 0), a_Chunk->GetNeighborChunk(a_Block.x + 1, a_Block.z));
+	AddBlock(a_Block + Vector3i(0, 0, -1), a_Chunk->GetNeighborChunk(a_Block.x, a_Block.z - 1));
+	AddBlock(a_Block + Vector3i(0, 0,  1), a_Chunk->GetNeighborChunk(a_Block.x, a_Block.z + 1));
+	if (a_Block.y > 0)
 	{
-		AddBlock(a_BlockX, a_BlockY - 1, a_BlockZ, a_Chunk);
+		AddBlock(a_Block + Vector3i(0, -1, 0), a_Chunk);
 	}
-	if (a_BlockY < cChunkDef::Height - 1)
+	if (a_Block.y < cChunkDef::Height - 1)
 	{
-		AddBlock(a_BlockX, a_BlockY + 1, a_BlockZ, a_Chunk);
+		AddBlock(a_Block + Vector3i(0, 1, 0), a_Chunk);
 	}
 }
 
@@ -47,12 +47,11 @@ void cSimulator::WakeUpArea(const cCuboid & a_Area)
 	area.ClampY(0, cChunkDef::Height - 1);
 
 	// Add all blocks, in a per-chunk manner:
-	int chunkStartX, chunkStartZ, chunkEndX, chunkEndZ;
-	cChunkDef::BlockToChunk(area.p1.x, area.p1.z, chunkStartX, chunkStartZ);
-	cChunkDef::BlockToChunk(area.p2.x, area.p2.z, chunkEndX,   chunkEndZ);
-	for (int cz = chunkStartZ; cz <= chunkEndZ; ++cz)
+	cChunkCoords ChunkStart = cChunkDef::BlockToChunk(area.p1);
+	cChunkCoords ChunkEnd = cChunkDef::BlockToChunk(area.p2);
+	for (int cz = ChunkStart.m_ChunkZ; cz <= ChunkEnd.m_ChunkZ; ++cz)
 	{
-		for (int cx = chunkStartX; cx <= chunkEndX; ++cx)
+		for (int cx = ChunkStart.m_ChunkX; cx <= ChunkEnd.m_ChunkX; ++cx)
 		{
 			m_World.DoWithChunk(cx, cz, [this, &area](cChunk & a_CBChunk) -> bool
 				{
@@ -73,7 +72,7 @@ void cSimulator::WakeUpArea(const cCuboid & a_Area)
 						{
 							for (int x = startX; x <= endX; ++x)
 							{
-								AddBlock(x, y, z, &a_CBChunk);
+								AddBlock({x, y, z}, &a_CBChunk);
 							}  // for x
 						}  // for z
 					}  // for y
diff --git a/src/Simulator/Simulator.h b/src/Simulator/Simulator.h
index ef0a3bf68..669680693 100644
--- a/src/Simulator/Simulator.h
+++ b/src/Simulator/Simulator.h
@@ -39,7 +39,7 @@ public:
 	}
 
 	/** Called when a block changes */
-	void WakeUp(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk);
+	void WakeUp(Vector3i a_Block, cChunk * a_Chunk);
 
 	/** Does the same processing as WakeUp, but for all blocks within the specified area.
 	Has better performance than calling WakeUp for each block individually, due to neighbor-checking.
@@ -55,7 +55,7 @@ protected:
 	friend class cChunk;  // Calls AddBlock() in its WakeUpSimulators() function, to speed things up
 
 	/** Called to simulate a new block */
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) = 0;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) = 0;
 
 	cWorld & m_World;
 } ;
diff --git a/src/Simulator/SimulatorManager.cpp b/src/Simulator/SimulatorManager.cpp
index 78c02fc07..a2740f707 100644
--- a/src/Simulator/SimulatorManager.cpp
+++ b/src/Simulator/SimulatorManager.cpp
@@ -58,11 +58,11 @@ void cSimulatorManager::SimulateChunk(std::chrono::milliseconds a_Dt, int a_Chun
 
 
 
-void cSimulatorManager::WakeUp(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cSimulatorManager::WakeUp(Vector3i a_Block, cChunk * a_Chunk)
 {
 	for (cSimulators::iterator itr = m_Simulators.begin(); itr != m_Simulators.end(); ++itr)
 	{
-		itr->first->WakeUp(a_BlockX, a_BlockY, a_BlockZ, a_Chunk);
+		itr->first->WakeUp(a_Block, a_Chunk);
 	}
 }
 
diff --git a/src/Simulator/SimulatorManager.h b/src/Simulator/SimulatorManager.h
index daa949157..98a60b4ee 100644
--- a/src/Simulator/SimulatorManager.h
+++ b/src/Simulator/SimulatorManager.h
@@ -36,7 +36,7 @@ public:
 	void SimulateChunk(std::chrono::milliseconds a_DT, int a_ChunkX, int a_ChunkZ, cChunk * a_Chunk);
 
 	/* Called when a single block changes, wakes all simulators up for the block and its face-neighbors. */
-	void WakeUp(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk);
+	void WakeUp(Vector3i a_Block, cChunk * a_Chunk);
 
 	/** Does the same processing as WakeUp, but for all blocks within the specified area.
 	Has better performance than calling WakeUp for each block individually, due to neighbor-checking.
diff --git a/src/Simulator/VaporizeFluidSimulator.cpp b/src/Simulator/VaporizeFluidSimulator.cpp
index 1d2db58fb..c023f88c9 100644
--- a/src/Simulator/VaporizeFluidSimulator.cpp
+++ b/src/Simulator/VaporizeFluidSimulator.cpp
@@ -20,26 +20,26 @@ cVaporizeFluidSimulator::cVaporizeFluidSimulator(cWorld & a_World, BLOCKTYPE a_F
 
 
 
-void cVaporizeFluidSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+void cVaporizeFluidSimulator::AddBlock(Vector3i a_Block, cChunk * a_Chunk)
 {
 	if (a_Chunk == nullptr)
 	{
 		return;
 	}
-	int RelX = a_BlockX - a_Chunk->GetPosX() * cChunkDef::Width;
-	int RelZ = a_BlockZ - a_Chunk->GetPosZ() * cChunkDef::Width;
-	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_BlockY, RelZ);
+	int RelX = a_Block.x - a_Chunk->GetPosX() * cChunkDef::Width;
+	int RelZ = a_Block.z - a_Chunk->GetPosZ() * cChunkDef::Width;
+	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_Block.y, RelZ);
 	if (
 		(BlockType == m_FluidBlock) ||
 		(BlockType == m_StationaryFluidBlock)
 	)
 	{
-		a_Chunk->SetBlock(RelX, a_BlockY, RelZ, E_BLOCK_AIR, 0);
+		a_Chunk->SetBlock(RelX, a_Block.y, RelZ, E_BLOCK_AIR, 0);
 		a_Chunk->BroadcastSoundEffect(
 			"block.fire.extinguish",
-			static_cast<double>(a_BlockX),
-			static_cast<double>(a_BlockY),
-			static_cast<double>(a_BlockZ),
+			static_cast<double>(a_Block.x),
+			static_cast<double>(a_Block.y),
+			static_cast<double>(a_Block.z),
 			1.0f,
 			0.6f
 		);
diff --git a/src/Simulator/VaporizeFluidSimulator.h b/src/Simulator/VaporizeFluidSimulator.h
index 8076972a8..7a7006309 100644
--- a/src/Simulator/VaporizeFluidSimulator.h
+++ b/src/Simulator/VaporizeFluidSimulator.h
@@ -25,7 +25,7 @@ public:
 	cVaporizeFluidSimulator(cWorld & a_World, BLOCKTYPE a_Fluid, BLOCKTYPE a_StationaryFluid);
 
 	// cSimulator overrides:
-	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override;
+	virtual void AddBlock(Vector3i a_Block, cChunk * a_Chunk) override;
 	virtual void Simulate(float a_Dt) override;
 } ;