Correct world height validations.

Unify the way we test block above the current one (Height - 1 instead of a_RelY + 1).
Allow generation of world of flat height = 255

src/BlockEntities/ChestEntity.cpp

@@ -80,7 +80,7 @@ void cChestEntity::UsedBy(cPlayer * a_Player)
 void cChestEntity::OpenNewWindow(void)
 {
 	// TODO: cats are an obstruction
-	if ((GetPosY() + 1 < cChunkDef::Height) && cBlockInfo::IsSolid(GetWorld()->GetBlock(GetPosX(), GetPosY() + 1, GetPosZ())))
+	if ((GetPosY() < cChunkDef::Height - 1) && cBlockInfo::IsSolid(GetWorld()->GetBlock(GetPosX(), GetPosY() + 1, GetPosZ())))
 	{
 		// Obstruction, don't open
 		return;
@@ -99,7 +99,7 @@ void cChestEntity::OpenNewWindow(void)
 		
 		virtual bool Item(cChestEntity * a_Chest) override
 		{
-			if ((a_Chest->GetPosY() + 1 < cChunkDef::Height) && cBlockInfo::IsSolid(a_Chest->GetWorld()->GetBlock(a_Chest->GetPosX(), a_Chest->GetPosY() + 1, a_Chest->GetPosZ())))
+			if ((a_Chest->GetPosY() < cChunkDef::Height - 1) && cBlockInfo::IsSolid(a_Chest->GetWorld()->GetBlock(a_Chest->GetPosX(), a_Chest->GetPosY() + 1, a_Chest->GetPosZ())))
 			{
 				// Obstruction, don't open
 				return false;

src/Blocks/BlockBigFlower.h

@@ -81,7 +81,7 @@ public:
 
 	virtual bool CanBeAt(cChunkInterface & a_ChunkInterface, int a_RelX, int a_RelY, int a_RelZ, const cChunk & a_Chunk) override
 	{
-		return ((a_RelY > 0) && (a_Chunk.GetBlock(a_RelX, a_RelY - 1, a_RelZ) != E_BLOCK_AIR) && (a_RelY < cChunkDef::Height) && ((a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ) == E_BLOCK_AIR) || (a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ) == E_BLOCK_BIG_FLOWER)));
+		return ((a_RelY > 0) && (a_Chunk.GetBlock(a_RelX, a_RelY - 1, a_RelZ) != E_BLOCK_AIR) && (a_RelY < cChunkDef::Height - 1) && ((a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ) == E_BLOCK_AIR) || (a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ) == E_BLOCK_BIG_FLOWER)));
 	}
 
 

src/Blocks/BlockDirt.h

@@ -59,7 +59,7 @@ public:
 			a_Chunk.GetWorld()->QueueLightChunk(a_Chunk.GetPosX(), a_Chunk.GetPosZ());
 			return;
 		}
-		else if (std::max(a_Chunk.GetBlockLight(a_RelX, a_RelY + 1, a_RelZ), a_Chunk.GetTimeAlteredLight(a_Chunk.GetSkyLight(a_RelX, a_RelY + 1, a_RelZ))) < 9)
+		else if ((a_RelY < cChunkDef::Height - 1) && std::max(a_Chunk.GetBlockLight(a_RelX, a_RelY + 1, a_RelZ), a_Chunk.GetTimeAlteredLight(a_Chunk.GetSkyLight(a_RelX, a_RelY + 1, a_RelZ))) < 9)
 		{
 			// Source block is not bright enough to spread
 			return;

src/Blocks/BlockFarmland.h

@@ -45,7 +45,7 @@ public:
 		}
 
 		// Farmland too dry. If nothing is growing on top, turn back to dirt:
-		BLOCKTYPE UpperBlock = (a_RelY >= cChunkDef::Height) ? E_BLOCK_AIR : a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ);
+		BLOCKTYPE UpperBlock = (a_RelY >= cChunkDef::Height - 1) ? E_BLOCK_AIR : a_Chunk.GetBlock(a_RelX, a_RelY + 1, a_RelZ);
 		switch (UpperBlock)
 		{
 			case E_BLOCK_CROPS:

src/Blocks/BlockFluid.h

@@ -99,7 +99,7 @@ public:
 		// Check if it's fuel:
 		BLOCKTYPE BlockType;
 		if (
-			((a_RelY + y < 0) || (a_RelY + y > cChunkDef::Height)) ||
+			((a_RelY + y < 0) || (a_RelY + y >= cChunkDef::Height)) ||
 			!a_Chunk.UnboundedRelGetBlockType(a_RelX + x, a_RelY + y, a_RelZ + z, BlockType) ||
 			!cFireSimulator::IsFuel(BlockType)
 		)
@@ -126,7 +126,7 @@ public:
 		for (size_t i = 0; i < ARRAYCOUNT(CrossCoords); i++)
 		{
 			if (
-				((RelY + CrossCoords[i].y >= 0) && (RelY + CrossCoords[i].y <= cChunkDef::Height)) &&
+				((RelY + CrossCoords[i].y >= 0) && (RelY + CrossCoords[i].y < cChunkDef::Height)) &&
 				a_Chunk.UnboundedRelGetBlockType(RelX + CrossCoords[i].x, RelY + CrossCoords[i].y, RelZ + CrossCoords[i].z, BlockType) &&
 				(BlockType == E_BLOCK_AIR)
 			)

src/Blocks/BlockPortal.h

@@ -55,7 +55,7 @@ public:
 
 	virtual bool CanBeAt(cChunkInterface & a_ChunkInterface, int a_RelX, int a_RelY, int a_RelZ, const cChunk & a_Chunk) override
 	{
-		if ((a_RelY <= 0) || (a_RelY >= cChunkDef::Height))
+		if ((a_RelY <= 0) || (a_RelY >= cChunkDef::Height - 1))
 		{
 			return false;  // In case someone places a portal with meta 1 or 2 at boundaries, and server tries to get invalid coords at Y - 1 or Y + 1
 		}

src/Chunk.cpp

@@ -931,7 +931,7 @@ void cChunk::ApplyWeatherToTop()
 			FastSetBlock(X, Height, Z, E_BLOCK_SNOW, TopMeta - 1);
 		}
 	}
-	else if (cBlockInfo::IsSnowable(TopBlock) && (Height + 1 < cChunkDef::Height))
+	else if (cBlockInfo::IsSnowable(TopBlock) && (Height < cChunkDef::Height - 1))
 	{
 		SetBlock(X, Height + 1, Z, E_BLOCK_SNOW, 0);
 	}
@@ -1253,7 +1253,7 @@ bool cChunk::UnboundedRelGetBlockLights(int a_RelX, int a_RelY, int a_RelZ, NIBB
 
 bool cChunk::UnboundedRelSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
 {
-	if ((a_RelY < 0) || (a_RelY > cChunkDef::Height))
+	if ((a_RelY < 0) || (a_RelY >= cChunkDef::Height))
 	{
 		LOGWARNING("UnboundedRelSetBlock(): requesting a block with a_RelY out of range: %d", a_RelY);
 		return false;
@@ -1274,7 +1274,7 @@ bool cChunk::UnboundedRelSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE
 
 bool cChunk::UnboundedRelFastSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta)
 {
-	if ((a_RelY < 0) || (a_RelY > cChunkDef::Height))
+	if ((a_RelY < 0) || (a_RelY >= cChunkDef::Height))
 	{
 		LOGWARNING("UnboundedRelFastSetBlock(): requesting a block with a_RelY out of range: %d", a_RelY);
 		return false;

src/ClientHandle.cpp

@@ -1006,6 +1006,12 @@ void cClientHandle::HandleLeftClick(int a_BlockX, int a_BlockY, int a_BlockZ, eB
 		int BlockY = a_BlockY;
 		int BlockZ = a_BlockZ;
 		AddFaceDirection(BlockX, BlockY, BlockZ, a_BlockFace);
+
+		if ((BlockY < 0) || (BlockY >= cChunkDef::Height))
+		{
+			return;
+		}
+
 		if (cBlockInfo::GetHandler(m_Player->GetWorld()->GetBlock(BlockX, BlockY, BlockZ))->IsClickedThrough())
 		{
 			a_BlockX = BlockX;

src/Entities/Boat.cpp

@@ -98,7 +98,7 @@ void cBoat::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 	SetSpeed(GetSpeed() * 0.97);  // Slowly decrease the speed
 
-	if ((POSY_TOINT < 0) || (POSY_TOINT > cChunkDef::Height))
+	if ((POSY_TOINT < 0) || (POSY_TOINT >= cChunkDef::Height))
 	{
 		return;
 	}

src/Entities/FallingBlock.cpp

@@ -77,7 +77,10 @@ void cFallingBlock::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		);
 		*/
 
-		cSandSimulator::FinishFalling(m_World, BlockX, BlockY + 1, BlockZ, m_BlockType, m_BlockMeta);
+		if (BlockY < cChunkDef::Height - 1)
+		{
+			cSandSimulator::FinishFalling(m_World, BlockX, BlockY + 1, BlockZ, m_BlockType, m_BlockMeta);
+		}
 		Destroy(true);
 		return;
 	}

src/Generating/FinishGen.cpp

@@ -571,7 +571,7 @@ void cFinishGenSnow::GenFinish(cChunkDesc & a_ChunkDesc)
 				continue;
 			}
 
-			if (!cBlockInfo::IsSnowable(a_ChunkDesc.GetBlockType(x, Height, z)) && (Height < cChunkDef::Height - 1))
+			if (!cBlockInfo::IsSnowable(a_ChunkDesc.GetBlockType(x, Height, z)) || (Height >= cChunkDef::Height - 1))
 			{
 				// The top block can't be snown over.
 				continue;

src/Generating/ShapeGen.cpp

@@ -41,7 +41,7 @@ public:
 		{
 			for (int x = 0; x < cChunkDef::Width; x++)
 			{
-				HEIGHTTYPE height = cChunkDef::GetHeight(heightMap, x, z) + 1;
+				int height = cChunkDef::GetHeight(heightMap, x, z) + 1;
 				Byte * shapeColumn = &(a_Shape[(x + 16 * z) * 256]);
 				for (int y = 0; y < height; y++)
 				{

src/Items/ItemDoor.h

@@ -34,7 +34,7 @@ public:
 		AddFaceDirection(a_BlockX, a_BlockY, a_BlockZ, a_BlockFace);
 
 		// Door (bottom block) can be placed in Y range of [1, 254]:
-		if ((a_BlockY < 1) || (a_BlockY + 2 >= cChunkDef::Height))
+		if ((a_BlockY < 1) || (a_BlockY >= cChunkDef::Height - 2))
 		{
 			return false;
 		}

src/MobSpawner.cpp

@@ -132,7 +132,7 @@ bool cMobSpawner::CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_R
 	BLOCKTYPE TargetBlock = E_BLOCK_AIR;
 	if (a_Chunk->UnboundedRelGetBlockType(a_RelX, a_RelY, a_RelZ, TargetBlock))
 	{
-		if ((a_RelY + 1 > cChunkDef::Height) || (a_RelY - 1 < 0))
+		if ((a_RelY >= cChunkDef::Height - 1) || (a_RelY <= 0))
 		{
 			return false;
 		}

src/Mobs/Monster.cpp

@@ -135,7 +135,7 @@ void cMonster::TickPathFinding()
 		{ 0, -1},
 	} ;
 	
-	if ((PosY - 1 < 0) || (PosY + 2 > cChunkDef::Height) /* PosY + 1 will never be true if PosY + 2 is not */)
+	if ((PosY - 1 < 0) || (PosY + 2 >= cChunkDef::Height) /* PosY + 1 will never be true if PosY + 2 is not */)
 	{
 		// Too low/high, can't really do anything
 		FinishPathFinding();

src/Mobs/Sheep.cpp

@@ -91,7 +91,7 @@ void cSheep::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 	int PosY = POSY_TOINT - 1;
 	int PosZ = POSZ_TOINT;
 
-	if ((PosY <= 0) || (PosY > cChunkDef::Height))
+	if ((PosY <= 0) || (PosY >= cChunkDef::Height))
 	{
 		return;
 	}

src/Simulator/FireSimulator.cpp

@@ -377,7 +377,7 @@ void cFireSimulator::RemoveFuelNeighbors(cChunk * a_Chunk, int a_RelX, int a_Rel
 		if (BlockType == E_BLOCK_TNT)
 		{
 			m_World.SpawnPrimedTNT(AbsX, Y, AbsZ, 0);
-			Neighbour->SetBlock(X, a_RelY + Y, Z, E_BLOCK_AIR, 0);
+			Neighbour->SetBlock(X, Y, Z, E_BLOCK_AIR, 0);
 			return;
 		}
 

src/Simulator/IncrementalRedstoneSimulator.cpp

@@ -31,7 +31,7 @@ void cIncrementalRedstoneSimulator::RedstoneAddBlock(int a_BlockX, int a_BlockY,
 	{
 		return;
 	}
-	else if ((a_BlockY < 0) || (a_BlockY > cChunkDef::Height))
+	else if ((a_BlockY < 0) || (a_BlockY >= cChunkDef::Height))
 	{
 		return;
 	}
@@ -556,7 +556,7 @@ void cIncrementalRedstoneSimulator::HandleRedstoneWire(int a_RelBlockX, int a_Re
 		if ((i >= 4) && (i <= 7))  // If we are currently checking for wire surrounding ourself one block above...
 		{
 			BLOCKTYPE Type = 0;
-			if (a_RelBlockY + 1 >= cChunkDef::Height)
+			if (a_RelBlockY >= cChunkDef::Height - 1)
 			{
 				continue;
 			}