canbeat-cleanup

24 files changed, 130 insertions, 82 deletions

diff --git a/src/Blocks/BlockBigFlower.h b/src/Blocks/BlockBigFlower.h
index 1b2c0d735..37c172747 100644
--- a/src/Blocks/BlockBigFlower.h
+++ b/src/Blocks/BlockBigFlower.h
@@ -25,9 +25,10 @@ private:
 		if (IsMetaTopPart(a_Meta))
 		{
 			BLOCKTYPE BottomType;
+			auto RootPosition = a_Position.addedY(-1);
 			if (
-				(a_Position.y < 1) ||
-				!a_World.GetBlockTypeMeta(a_Position - Vector3i(0, 1, 0), BottomType, a_Meta) ||
+				!cChunkDef::IsValidHeight(RootPosition) ||
+				!a_World.GetBlockTypeMeta(RootPosition, BottomType, a_Meta) ||
 				(BottomType != E_BLOCK_BIG_FLOWER)
 			)
 			{
@@ -104,7 +105,7 @@ private:
 		// Both parts can only that they're rooted in grass.
 
 		const auto RootPosition = a_Position.addedY(IsMetaTopPart(a_Meta) ? -2 : -1);
-		return (RootPosition.y >= 0) && IsBlockTypeOfDirt(a_Chunk.GetBlock(RootPosition));
+		return cChunkDef::IsValidHeight(RootPosition) && IsBlockTypeOfDirt(a_Chunk.GetBlock(RootPosition));
 	}
 
 
diff --git a/src/Blocks/BlockCactus.h b/src/Blocks/BlockCactus.h
index 23c4d3421..9b1461cb8 100644
--- a/src/Blocks/BlockCactus.h
+++ b/src/Blocks/BlockCactus.h
@@ -20,11 +20,12 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto SurfacePosition = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(SurfacePosition))
 		{
 			return false;
 		}
-		BLOCKTYPE Surface = a_Chunk.GetBlock(a_Position.addedY(-1));
+		BLOCKTYPE Surface = a_Chunk.GetBlock(SurfacePosition);
 		if ((Surface != E_BLOCK_SAND) && (Surface != E_BLOCK_CACTUS))
 		{
 			// Cactus can only be placed on sand and itself
@@ -75,25 +76,25 @@ private:
 	virtual int Grow(cChunk & a_Chunk, Vector3i a_RelPos, int a_NumStages = 1) const override
 	{
 		// Check the total height of the cacti blocks here:
-		int top = a_RelPos.y + 1;
+		auto Top = a_RelPos.addedY(1);
 		while (
-			(top < cChunkDef::Height) &&
-			(a_Chunk.GetBlock({a_RelPos.x, top, a_RelPos.z}) == E_BLOCK_CACTUS)
+			cChunkDef::IsValidHeight(Top) &&
+			(a_Chunk.GetBlock(Top) == E_BLOCK_CACTUS)
 		)
 		{
-			++top;
+			Top.y++;
 		}
-		int bottom = a_RelPos.y - 1;
+		auto Bottom = a_RelPos.addedY(-1);
 		while (
-			(bottom > 0) &&
-			(a_Chunk.GetBlock({a_RelPos.x, bottom, a_RelPos.z}) == E_BLOCK_CACTUS)
+			cChunkDef::IsValidHeight(Bottom) &&
+			(a_Chunk.GetBlock(Bottom) == E_BLOCK_CACTUS)
 		)
 		{
-			--bottom;
+			--Bottom.y;
 		}
 
 		// Refuse if already too high:
-		auto numToGrow = std::min(a_NumStages, a_Chunk.GetWorld()->GetMaxCactusHeight() + 1 - (top - bottom));
+		auto numToGrow = std::min(a_NumStages, a_Chunk.GetWorld()->GetMaxCactusHeight() + 1 - (Top.y - Bottom.y));
 		if (numToGrow <= 0)
 		{
 			return 0;
@@ -102,14 +103,14 @@ private:
 		BLOCKTYPE blockType;
 		for (int i = 0; i < numToGrow; ++i)
 		{
-			Vector3i pos(a_RelPos.x, top + i, a_RelPos.z);
-			if (!a_Chunk.UnboundedRelGetBlockType(pos, blockType) || (blockType != E_BLOCK_AIR))
+			auto NewTop = Top.addedY(i);
+			if (!a_Chunk.UnboundedRelGetBlockType(NewTop, blockType) || (blockType != E_BLOCK_AIR))
 			{
 				// Cannot grow there
 				return i;
 			}
 
-			a_Chunk.UnboundedRelFastSetBlock(pos, E_BLOCK_CACTUS, 0);
+			a_Chunk.UnboundedRelFastSetBlock(NewTop, E_BLOCK_CACTUS, 0);
 
 			// Check surroundings. Cacti may ONLY be surrounded by non-solid blocks; if they aren't, drop as pickup and bail out the growing
 			static const Vector3i neighborOffsets[] =
@@ -122,7 +123,7 @@ private:
 			for (const auto & ofs: neighborOffsets)
 			{
 				if (
-					a_Chunk.UnboundedRelGetBlockType(pos + ofs, blockType) &&
+					a_Chunk.UnboundedRelGetBlockType(NewTop + ofs, blockType) &&
 					(
 						cBlockInfo::IsSolid(blockType) ||
 						(blockType == E_BLOCK_LAVA) ||
@@ -131,7 +132,7 @@ private:
 				)
 				{
 					// Remove the cactus
-					auto absPos = a_Chunk.RelativeToAbsolute(pos);
+					auto absPos = a_Chunk.RelativeToAbsolute(NewTop);
 					a_Chunk.GetWorld()->DropBlockAsPickups(absPos);
 					return i + 1;
 				}
@@ -143,7 +144,8 @@ private:
 	virtual PlantAction CanGrow(cChunk & a_Chunk, Vector3i a_RelPos) const override
 	{
 		// Only allow growing if there's an air block above:
-		if (((a_RelPos.y + 1) < cChunkDef::Height) && (a_Chunk.GetBlock(a_RelPos.addedY(1)) == E_BLOCK_AIR))
+		const auto RelPosAbove = a_RelPos.addedY(1);
+		if (cChunkDef::IsValidHeight(RelPosAbove) && (a_Chunk.GetBlock(RelPosAbove) == E_BLOCK_AIR))
 		{
 			return Super::CanGrow(a_Chunk, a_RelPos);
 		}
diff --git a/src/Blocks/BlockCarpet.h b/src/Blocks/BlockCarpet.h
index 841e94b11..2477ee344 100644
--- a/src/Blocks/BlockCarpet.h
+++ b/src/Blocks/BlockCarpet.h
@@ -27,7 +27,8 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		return (a_Position.y > 0) && (a_Chunk.GetBlock(a_Position.addedY(-1)) != E_BLOCK_AIR);
+		const auto PosBelow = a_Position.addedY(-1);
+		return cChunkDef::IsValidHeight(PosBelow) && (a_Chunk.GetBlock(PosBelow) != E_BLOCK_AIR);
 	}
 
 
diff --git a/src/Blocks/BlockCocoaPod.h b/src/Blocks/BlockCocoaPod.h
index e018388c5..85dc42fbf 100644
--- a/src/Blocks/BlockCocoaPod.h
+++ b/src/Blocks/BlockCocoaPod.h
@@ -43,7 +43,10 @@ private:
 		auto LogPos = AddFaceDirection(a_Position, BlockFace, true);
 		BLOCKTYPE BlockType;
 		NIBBLETYPE BlockMeta;
-		a_Chunk.UnboundedRelGetBlock(LogPos, BlockType, BlockMeta);
+		if (!a_Chunk.UnboundedRelGetBlock(LogPos, BlockType, BlockMeta))
+		{
+			return true;
+		}
 		return ((BlockType == E_BLOCK_LOG) && ((BlockMeta & 0x03) == E_META_LOG_JUNGLE));
 	}
 
diff --git a/src/Blocks/BlockComparator.h b/src/Blocks/BlockComparator.h
index 18aa2a8b9..815bbe6a1 100644
--- a/src/Blocks/BlockComparator.h
+++ b/src/Blocks/BlockComparator.h
@@ -154,14 +154,15 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
 		BLOCKTYPE BelowBlock;
 		NIBBLETYPE BelowBlockMeta;
-		a_Chunk.GetBlockTypeMeta(a_Position.addedY(-1), BelowBlock, BelowBlockMeta);
+		a_Chunk.GetBlockTypeMeta(BelowPos, BelowBlock, BelowBlockMeta);
 
 		if (cBlockInfo::FullyOccupiesVoxel(BelowBlock))
 		{
diff --git a/src/Blocks/BlockCrops.h b/src/Blocks/BlockCrops.h
index b323ace10..59413ba08 100644
--- a/src/Blocks/BlockCrops.h
+++ b/src/Blocks/BlockCrops.h
@@ -118,7 +118,14 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		return (a_Position.y > 0) && (a_Chunk.GetBlock(a_Position.addedY(-1)) == E_BLOCK_FARMLAND);
+		const auto BlockBelow = a_Position.addedY(-1);
+
+		if (!cChunkDef::IsValidHeight(BlockBelow))
+		{
+			return false;
+		}
+
+		return a_Chunk.GetBlock(BlockBelow) == E_BLOCK_FARMLAND;
 	}
 
 
diff --git a/src/Blocks/BlockDeadBush.h b/src/Blocks/BlockDeadBush.h
index 080dd150c..884b6f686 100644
--- a/src/Blocks/BlockDeadBush.h
+++ b/src/Blocks/BlockDeadBush.h
@@ -29,12 +29,13 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto PosBelow = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(PosBelow))
 		{
 			return false;
 		}
 
-		BLOCKTYPE BelowBlock = a_Chunk.GetBlock(a_Position.addedY(-1));
+		BLOCKTYPE BelowBlock = a_Chunk.GetBlock(PosBelow);
 		switch (BelowBlock)
 		{
 			case E_BLOCK_CLAY:
diff --git a/src/Blocks/BlockDoor.h b/src/Blocks/BlockDoor.h
index 1b5c33d46..45102fd01 100644
--- a/src/Blocks/BlockDoor.h
+++ b/src/Blocks/BlockDoor.h
@@ -191,14 +191,18 @@ private:
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
 		// CanBeAt is also called on placement, so the top part can't check for the bottom part.
-		// Both parts can only that their base is a valid block.
+		// Both parts can only that the base of the door (i.e. -2 for a door top) is a valid block.
+		const auto BasePosition = a_Position.addedY(((a_Meta & 0x8) == 0x8) ? -2 : -1);
+		if (!cChunkDef::IsValidHeight(BasePosition))
+		{
+			return false;
+		}
 
 		BLOCKTYPE BlockType;
 		NIBBLETYPE BlockMeta;
-		const auto BasePosition = a_Position.addedY(((a_Meta & 0x8) == 0x8) ? -2 : -1);
 		a_Chunk.GetBlockTypeMeta(BasePosition, BlockType, BlockMeta);
 
-		return (BasePosition.y >= 0) && CanBeOn(BlockType, BlockMeta);
+		return CanBeOn(BlockType, BlockMeta);
 	}
 
 
@@ -216,9 +220,10 @@ private:
 		if ((Meta & 0x08) != 0)
 		{
 			// The coords are pointing at the top part of the door
-			if (a_BlockPos.y > 0)
+			const auto BottomPos = a_BlockPos.addedY(-1);
+			if (cChunkDef::IsValidHeight(BottomPos))
 			{
-				NIBBLETYPE DownMeta = a_ChunkInterface.GetBlockMeta(a_BlockPos.addedY(-1));
+				NIBBLETYPE DownMeta = a_ChunkInterface.GetBlockMeta(BottomPos);
 				return static_cast<NIBBLETYPE>((DownMeta & 0x07) | 0x08 | (Meta << 4));
 			}
 			// This is the top part of the door at the bottommost layer of the world, there's no bottom:
@@ -227,9 +232,10 @@ private:
 		else
 		{
 			// The coords are pointing at the bottom part of the door
-			if (a_BlockPos.y < cChunkDef::Height - 1)
+			const auto TopPos = a_BlockPos.addedY(1);
+			if (cChunkDef::IsValidHeight(TopPos))
 			{
-				NIBBLETYPE UpMeta = a_ChunkInterface.GetBlockMeta(a_BlockPos.addedY(1));
+				NIBBLETYPE UpMeta = a_ChunkInterface.GetBlockMeta(TopPos);
 				return static_cast<NIBBLETYPE>(Meta | (UpMeta << 4));
 			}
 			// This is the bottom part of the door at the topmost layer of the world, there's no top:
diff --git a/src/Blocks/BlockFlower.h b/src/Blocks/BlockFlower.h
index 023ba4a37..ef140e9b2 100644
--- a/src/Blocks/BlockFlower.h
+++ b/src/Blocks/BlockFlower.h
@@ -30,7 +30,9 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		return (a_Position.y > 0) && IsBlockTypeOfDirt(a_Chunk.GetBlock(a_Position.addedY(-1)));
+		const auto BottomPos = a_Position.addedY(-1);
+
+		return cChunkDef::IsValidHeight(BottomPos) && IsBlockTypeOfDirt(a_Chunk.GetBlock(BottomPos));
 	}
 
 
diff --git a/src/Blocks/BlockMushroom.h b/src/Blocks/BlockMushroom.h
index bed16c557..9e4378d4e 100644
--- a/src/Blocks/BlockMushroom.h
+++ b/src/Blocks/BlockMushroom.h
@@ -23,14 +23,15 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BasePos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BasePos))
 		{
 			return false;
 		}
 
 		// TODO: Cannot be at too much daylight
 
-		switch (a_Chunk.GetBlock(a_Position.addedY(-1)))
+		switch (a_Chunk.GetBlock(BasePos))
 		{
 			case E_BLOCK_GLASS:
 			case E_BLOCK_CACTUS:
diff --git a/src/Blocks/BlockNetherWart.h b/src/Blocks/BlockNetherWart.h
index 43081d511..c0686afc6 100644
--- a/src/Blocks/BlockNetherWart.h
+++ b/src/Blocks/BlockNetherWart.h
@@ -60,7 +60,8 @@ private:
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
 		// Needs to be placed on top of a Soulsand block:
-		return (a_Position.y > 0) && (a_Chunk.GetBlock(a_Position.addedY(-1)) == E_BLOCK_SOULSAND);
+		const auto BasePos = a_Position.addedY(-1);
+		return cChunkDef::IsValidHeight(BasePos) && (a_Chunk.GetBlock(BasePos) == E_BLOCK_SOULSAND);
 	}
 
 
diff --git a/src/Blocks/BlockPortal.h b/src/Blocks/BlockPortal.h
index 05daa9337..f4b5a50bd 100644
--- a/src/Blocks/BlockPortal.h
+++ b/src/Blocks/BlockPortal.h
@@ -51,9 +51,9 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if ((a_Position.y <= 0) || (a_Position.y >= cChunkDef::Height - 1))
+		if (!cChunkDef::IsValidHeight(a_Position.addedY(-1)) || !cChunkDef::IsValidHeight(a_Position.addedY(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.
+			return false;  // Must be 1 away from the boundary, there will always be another portal or an obsidian between the portal block and the boundary.
 		}
 
 		switch (a_Meta)
diff --git a/src/Blocks/BlockPressurePlate.h b/src/Blocks/BlockPressurePlate.h
index 6d852bfc0..d69234cee 100644
--- a/src/Blocks/BlockPressurePlate.h
+++ b/src/Blocks/BlockPressurePlate.h
@@ -22,14 +22,15 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto PosBelow = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(PosBelow))
 		{
 			return false;
 		}
 
 		BLOCKTYPE Block;
 		NIBBLETYPE BlockMeta;
-		a_Chunk.GetBlockTypeMeta(a_Position.addedY(-1), Block, BlockMeta);
+		a_Chunk.GetBlockTypeMeta(PosBelow, Block, BlockMeta);
 
 		// upside down slabs
 		if (cBlockSlabHandler::IsAnySlabType(Block))
diff --git a/src/Blocks/BlockRail.h b/src/Blocks/BlockRail.h
index 4e2e6211f..48f20a86b 100644
--- a/src/Blocks/BlockRail.h
+++ b/src/Blocks/BlockRail.h
@@ -177,11 +177,17 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, NIBBLETYPE a_Meta) const override
 	{
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
+		{
+			return false;
+		}
+
 		BLOCKTYPE BelowBlock;
 		NIBBLETYPE BelowBlockMeta;
-		a_Chunk.GetBlockTypeMeta(a_Position.addedY(-1), BelowBlock, BelowBlockMeta);
+		a_Chunk.GetBlockTypeMeta(BelowPos, BelowBlock, BelowBlockMeta);
 
-		if ((a_Position.y <= 0) || !CanBeSupportedBy(BelowBlock, BelowBlockMeta))
+		if (!CanBeSupportedBy(BelowBlock, BelowBlockMeta))
 		{
 			return false;
 		}
diff --git a/src/Blocks/BlockRedstoneRepeater.h b/src/Blocks/BlockRedstoneRepeater.h
index 893691d7b..5476df8eb 100644
--- a/src/Blocks/BlockRedstoneRepeater.h
+++ b/src/Blocks/BlockRedstoneRepeater.h
@@ -109,14 +109,15 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
 		BLOCKTYPE BelowBlock;
 		NIBBLETYPE BelowBlockMeta;
-		a_Chunk.GetBlockTypeMeta(a_Position.addedY(-1), BelowBlock, BelowBlockMeta);
+		a_Chunk.GetBlockTypeMeta(BelowPos, BelowBlock, BelowBlockMeta);
 
 		if (cBlockInfo::FullyOccupiesVoxel(BelowBlock))
 		{
diff --git a/src/Blocks/BlockRedstoneWire.h b/src/Blocks/BlockRedstoneWire.h
index de8e59a40..f0f3baecc 100644
--- a/src/Blocks/BlockRedstoneWire.h
+++ b/src/Blocks/BlockRedstoneWire.h
@@ -22,14 +22,15 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
 		BLOCKTYPE BelowBlock;
 		NIBBLETYPE BelowBlockMeta;
-		a_Chunk.GetBlockTypeMeta(a_Position.addedY(-1), BelowBlock, BelowBlockMeta);
+		a_Chunk.GetBlockTypeMeta(BelowPos, BelowBlock, BelowBlockMeta);
 
 		if (cBlockInfo::FullyOccupiesVoxel(BelowBlock))
 		{
diff --git a/src/Blocks/BlockSapling.h b/src/Blocks/BlockSapling.h
index d32b9b449..ae8a190a3 100644
--- a/src/Blocks/BlockSapling.h
+++ b/src/Blocks/BlockSapling.h
@@ -31,7 +31,8 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		return (a_Position.y > 0) && IsBlockTypeOfDirt(a_Chunk.GetBlock(a_Position.addedY(-1)));
+		const auto BelowPos = a_Position.addedY(-1);
+		return cChunkDef::IsValidHeight(BelowPos) && IsBlockTypeOfDirt(a_Chunk.GetBlock(BelowPos));
 	}
 
 
diff --git a/src/Blocks/BlockSignPost.h b/src/Blocks/BlockSignPost.h
index b96498cbd..89da77fbb 100644
--- a/src/Blocks/BlockSignPost.h
+++ b/src/Blocks/BlockSignPost.h
@@ -30,12 +30,13 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
-		BLOCKTYPE Type = a_Chunk.GetBlock(a_Position.addedY(-1));
+		BLOCKTYPE Type = a_Chunk.GetBlock(BelowPos);
 		return (Type == E_BLOCK_SIGN_POST) || (Type == E_BLOCK_WALLSIGN) || cBlockInfo::IsSolid(Type);
 	}
 
diff --git a/src/Blocks/BlockSnow.h b/src/Blocks/BlockSnow.h
index f3fa87a1b..51361ce17 100644
--- a/src/Blocks/BlockSnow.h
+++ b/src/Blocks/BlockSnow.h
@@ -69,11 +69,11 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
-		auto BelowPos = a_Position.addedY(-1);
 		auto BlockBelow = a_Chunk.GetBlock(BelowPos);
 		auto MetaBelow = a_Chunk.GetMeta(BelowPos);
 		return CanBeOn(BlockBelow, MetaBelow);
diff --git a/src/Blocks/BlockStandingBanner.h b/src/Blocks/BlockStandingBanner.h
index 391b7fde7..177e9a68c 100644
--- a/src/Blocks/BlockStandingBanner.h
+++ b/src/Blocks/BlockStandingBanner.h
@@ -31,12 +31,13 @@ public:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y < 1)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
-		return cBlockInfo::IsSolid(a_Chunk.GetBlock(a_Position.addedY(-1)));
+		return cBlockInfo::IsSolid(a_Chunk.GetBlock(BelowPos));
 	}
 
 
diff --git a/src/Blocks/BlockStems.h b/src/Blocks/BlockStems.h
index 11cd83967..9d598003d 100644
--- a/src/Blocks/BlockStems.h
+++ b/src/Blocks/BlockStems.h
@@ -58,7 +58,8 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		return (a_Position.y > 0) && (a_Chunk.GetBlock(a_Position.addedY(-1)) == E_BLOCK_FARMLAND);
+		const auto BelowPos = a_Position.addedY(-1);
+		return cChunkDef::IsValidHeight(BelowPos) && (a_Chunk.GetBlock(BelowPos) == E_BLOCK_FARMLAND);
 	}
 
 
diff --git a/src/Blocks/BlockSugarCane.h b/src/Blocks/BlockSugarCane.h
index cffe667e5..1f6c8a8fa 100644
--- a/src/Blocks/BlockSugarCane.h
+++ b/src/Blocks/BlockSugarCane.h
@@ -29,12 +29,13 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
-		switch (a_Chunk.GetBlock(a_Position.addedY(-1)))
+		switch (a_Chunk.GetBlock(BelowPos))
 		{
 			case E_BLOCK_DIRT:
 			case E_BLOCK_GRASS:
@@ -43,16 +44,16 @@ private:
 			{
 				static const Vector3i Coords[] =
 				{
-					{-1, -1,  0},
-					{ 1, -1,  0},
-					{ 0, -1, -1},
-					{ 0, -1,  1},
+					{-1, 0,  0},
+					{ 1, 0,  0},
+					{ 0, 0, -1},
+					{ 0, 0,  1},
 				} ;
 				for (size_t i = 0; i < ARRAYCOUNT(Coords); i++)
 				{
 					BLOCKTYPE BlockType;
 					NIBBLETYPE BlockMeta;
-					if (!a_Chunk.UnboundedRelGetBlock(a_Position + Coords[i], BlockType, BlockMeta))
+					if (!a_Chunk.UnboundedRelGetBlock(BelowPos + Coords[i], BlockType, BlockMeta))
 					{
 						// Too close to the edge, cannot simulate
 						return true;
@@ -90,31 +91,36 @@ private:
 	virtual int Grow(cChunk & a_Chunk, Vector3i a_RelPos, int a_NumStages = 1) const override
 	{
 		// Check the total height of the sugarcane blocks here:
-		int top = a_RelPos.y + 1;
+		auto top = a_RelPos.addedY(1);
 		while (
-			(top < cChunkDef::Height) &&
-			(a_Chunk.GetBlock({a_RelPos.x, top, a_RelPos.z}) == E_BLOCK_SUGARCANE)
+			cChunkDef::IsValidHeight(top) &&
+			(a_Chunk.GetBlock(top) == E_BLOCK_SUGARCANE)
 		)
 		{
-			++top;
+			++top.y;
 		}
-		int bottom = a_RelPos.y - 1;
+		auto bottom = a_RelPos.addedY(-1);
 		while (
-			(bottom > 0) &&
-			(a_Chunk.GetBlock({a_RelPos.x, bottom, a_RelPos.z}) == E_BLOCK_SUGARCANE)
+			cChunkDef::IsValidHeight(bottom) &&
+			(a_Chunk.GetBlock(bottom) == E_BLOCK_SUGARCANE)
 		)
 		{
-			--bottom;
+			--bottom.y;
 		}
 
 		// Grow by at most a_NumStages, but no more than max height:
-		auto toGrow = std::min(a_NumStages, a_Chunk.GetWorld()->GetMaxSugarcaneHeight() + 1 - (top - bottom));
-		Vector3i topPos(a_RelPos.x, top, a_RelPos.z);
+		auto toGrow = std::min(a_NumStages, a_Chunk.GetWorld()->GetMaxSugarcaneHeight() + 1 - (top.y - bottom.y));
 		for (int i = 0; i < toGrow; i++)
 		{
-			if (a_Chunk.GetBlock(topPos.addedY(i)) == E_BLOCK_AIR)
+			const auto NewTop = top.addedY(i);
+			if (!cChunkDef::IsValidHeight(NewTop))
 			{
-				a_Chunk.SetBlock(topPos.addedY(i), E_BLOCK_SUGARCANE, 0);
+				return i;
+			}
+
+			if (a_Chunk.GetBlock(NewTop) == E_BLOCK_AIR)
+			{
+				a_Chunk.SetBlock(NewTop, E_BLOCK_SUGARCANE, 0);
 			}
 			else
 			{
diff --git a/src/Blocks/BlockTallGrass.h b/src/Blocks/BlockTallGrass.h
index ea638c878..a30c7ce05 100644
--- a/src/Blocks/BlockTallGrass.h
+++ b/src/Blocks/BlockTallGrass.h
@@ -54,12 +54,13 @@ private:
 
 	virtual bool CanBeAt(const cChunk & a_Chunk, const Vector3i a_Position, const NIBBLETYPE a_Meta) const override
 	{
-		if (a_Position.y <= 0)
+		const auto BelowPos = a_Position.addedY(-1);
+		if (!cChunkDef::IsValidHeight(BelowPos))
 		{
 			return false;
 		}
 
-		BLOCKTYPE BelowBlock = a_Chunk.GetBlock(a_Position.addedY(-1));
+		BLOCKTYPE BelowBlock = a_Chunk.GetBlock(BelowPos);
 		return IsBlockTypeOfDirt(BelowBlock);
 	}
 
@@ -70,7 +71,8 @@ private:
 	/** Growing a tall grass produces a big flower (2-block high fern or double-tall grass). */
 	virtual int Grow(cChunk & a_Chunk, Vector3i a_RelPos, int a_NumStages = 1) const override
 	{
-		if (a_RelPos.y > (cChunkDef::Height - 2))
+		const auto TopPos = a_RelPos.addedY(1);
+		if (!cChunkDef::IsValidHeight(TopPos))
 		{
 			return 0;
 		}
@@ -83,7 +85,7 @@ private:
 			default:                      return 0;
 		}
 		a_Chunk.SetBlock(a_RelPos,           E_BLOCK_BIG_FLOWER, largeFlowerMeta);
-		a_Chunk.SetBlock(a_RelPos.addedY(1), E_BLOCK_BIG_FLOWER, E_META_BIG_FLOWER_TOP);
+		a_Chunk.SetBlock(TopPos, E_BLOCK_BIG_FLOWER, E_META_BIG_FLOWER_TOP);
 		return 1;
 	}
 
diff --git a/src/Blocks/BlockVines.h b/src/Blocks/BlockVines.h
index a23ba1489..edbd30f36 100644
--- a/src/Blocks/BlockVines.h
+++ b/src/Blocks/BlockVines.h
@@ -119,15 +119,16 @@ private:
 		}
 
 		// Check if vine above us, add its meta to MaxMeta:
-		if ((a_Position.y < cChunkDef::Height - 1) && (a_Chunk.GetBlock(a_Position.addedY(1)) == E_BLOCK_VINES))
+		const auto AbovePos = a_Position.addedY(1);
+		if (cChunkDef::IsValidHeight(AbovePos) && (a_Chunk.GetBlock(AbovePos) == E_BLOCK_VINES))
 		{
-			MaxMeta |= a_Chunk.GetMeta(a_Position.addedY(1));
+			MaxMeta |= a_Chunk.GetMeta(AbovePos);
 		}
 
 		NIBBLETYPE Common = a_CurrentMeta & MaxMeta;  // Neighbors that we have and are legal.
 		if (Common != a_CurrentMeta)
 		{
-			bool HasTop = (a_Position.y < (cChunkDef::Height - 1)) && IsBlockAttachable(a_Chunk.GetBlock(a_Position.addedY(1)));
+			bool HasTop = cChunkDef::IsValidHeight(AbovePos) && IsBlockAttachable(a_Chunk.GetBlock(AbovePos));
 			if ((Common == 0) && !HasTop)  // Meta equals 0 also means top. Make a last-ditch attempt to save the vine.
 			{
 				return VINE_LOST_SUPPORT;