1 files changed, 182 insertions, 112 deletions

diff --git a/src/Blocks/BlockPiston.cpp b/src/Blocks/BlockPiston.cpp
index 94782a7ed..1da2a61ec 100644
--- a/src/Blocks/BlockPiston.cpp
+++ b/src/Blocks/BlockPiston.cpp
@@ -7,25 +7,12 @@
 #include "BlockInServerPluginInterface.h"
 #include "ChunkInterface.h"
 
+#include <vector>
+#include <array>
 
 
 
 
-#define AddPistonDir(x, y, z, dir, amount) \
-	switch (dir & 0x07) \
-	{ \
-		case 0: (y) -= (amount); break; \
-		case 1: (y) += (amount); break; \
-		case 2: (z) -= (amount); break; \
-		case 3: (z) += (amount); break; \
-		case 4: (x) -= (amount); break; \
-		case 5: (x) += (amount); break; \
-		default: \
-		{ \
-			LOGWARNING("%s: invalid direction %d, ignoring", __FUNCTION__, dir & 0x07); \
-			break; \
-		} \
-	}
 
 #define PISTON_MAX_PUSH_DISTANCE 12
 
@@ -43,16 +30,15 @@ cBlockPistonHandler::cBlockPistonHandler(BLOCKTYPE a_BlockType)
 
 void cBlockPistonHandler::OnDestroyed(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, int a_BlockX, int a_BlockY, int a_BlockZ)
 {
-	NIBBLETYPE OldMeta = a_ChunkInterface.GetBlockMeta(a_BlockX, a_BlockY, a_BlockZ);
+	Vector3i blockPos(a_BlockX, a_BlockY, a_BlockZ);
 
-	int newX = a_BlockX;
-	int newY = a_BlockY;
-	int newZ = a_BlockZ;
-	AddPistonDir(newX, newY, newZ, OldMeta, 1);
+	// Get the extension of the piston
+	NIBBLETYPE OldMeta = a_ChunkInterface.GetBlockMeta(blockPos.x, blockPos.y, blockPos.z);
+	blockPos += MetadataToOffset(OldMeta);
 
-	if (a_ChunkInterface.GetBlock(newX, newY, newZ) == E_BLOCK_PISTON_EXTENSION)
+	if (a_ChunkInterface.GetBlock(blockPos) == E_BLOCK_PISTON_EXTENSION)
 	{
-		a_ChunkInterface.SetBlock(newX, newY, newZ, E_BLOCK_AIR, 0);
+		a_ChunkInterface.SetBlock(blockPos.x, blockPos.y, blockPos.z, E_BLOCK_AIR, 0);
 	}
 }
 
@@ -86,105 +72,187 @@ bool cBlockPistonHandler::GetPlacementBlockTypeMeta(
 
 
 
-int cBlockPistonHandler::FirstPassthroughBlock(int a_PistonX, int a_PistonY, int a_PistonZ, NIBBLETYPE pistonmeta, cWorld * a_World)
+Vector3i cBlockPistonHandler::MetadataToOffset(NIBBLETYPE a_PistonMeta)
 {
-	// Examine each of the 12 blocks ahead of the piston:
-	for (int ret = 0; ret < PISTON_MAX_PUSH_DISTANCE; ret++)
+	switch (a_PistonMeta & 0x07)
 	{
-		BLOCKTYPE currBlock;
-		NIBBLETYPE currMeta;
-		AddPistonDir(a_PistonX, a_PistonY, a_PistonZ, pistonmeta, 1);
-		a_World->GetBlockTypeMeta(a_PistonX, a_PistonY, a_PistonZ, currBlock, currMeta);
-		if (cBlockInfo::IsPistonBreakable(currBlock))
+		case 0: return Vector3i( 0, -1,  0);
+		case 1: return Vector3i( 0,  1,  0);
+		case 2: return Vector3i( 0,  0, -1);
+		case 3: return Vector3i( 0,  0,  1);
+		case 4: return Vector3i(-1,  0,  0);
+		case 5: return Vector3i( 1,  0,  0);
+		default:
 		{
-			// This block breaks when pushed, extend up to here
-			return ret;
+			LOGWARNING("%s: invalid direction %d, ignoring", __FUNCTION__, a_PistonMeta & 0x07);
+			ASSERT(!"Invalid direction");
+			return Vector3i();
 		}
-		if (!CanPush(currBlock, currMeta))
+	}
+}
+
+
+
+
+
+void cBlockPistonHandler::PushBlocks(
+	const Vector3iSet & a_BlocksToPush,
+	cWorld * a_World, const Vector3i & a_PushDir
+)
+{
+	// Sort blocks to move the blocks first, which are farest away from the piston
+	// This prevents the overwriting of existing blocks
+	std::vector<Vector3i> sortedBlocks(a_BlocksToPush.begin(), a_BlocksToPush.end());
+	std::sort(sortedBlocks.begin(), sortedBlocks.end(), [a_PushDir](const Vector3i & a, const Vector3i & b)
+	{
+		return a.Dot(a_PushDir) > b.Dot(a_PushDir);
+	});
+
+	// Move every block
+	BLOCKTYPE moveBlock;
+	NIBBLETYPE moveMeta;
+	for (auto & moveBlockPos : sortedBlocks)
+	{
+		a_World->GetBlockTypeMeta(moveBlockPos.x, moveBlockPos.y, moveBlockPos.z, moveBlock, moveMeta);
+		a_World->SetBlock(moveBlockPos.x, moveBlockPos.y, moveBlockPos.z, E_BLOCK_AIR, 0);
+
+		moveBlockPos += a_PushDir;
+		if (cBlockInfo::IsPistonBreakable(moveBlock))
+		{
+			// Block is breakable, drop it
+			cBlockHandler * Handler = BlockHandler(moveBlock);
+			if (Handler->DoesDropOnUnsuitable())
+			{
+				cChunkInterface ChunkInterface(a_World->GetChunkMap());
+				cBlockInServerPluginInterface PluginInterface(*a_World);
+				Handler->DropBlock(ChunkInterface, *a_World, PluginInterface, nullptr,
+					moveBlockPos.x, moveBlockPos.y, moveBlockPos.z
+				);
+			}
+		} else
 		{
-			// This block cannot be pushed at all, the piston can't extend
-			return -1;
+			// Not breakable, just move it
+			a_World->SetBlock(moveBlockPos.x, moveBlockPos.y, moveBlockPos.z, moveBlock, moveMeta);
 		}
 	}
-	// There is no space for the blocks to move, piston can't extend
-	return -1;
 }
 
 
 
 
 
-void cBlockPistonHandler::ExtendPiston(int a_BlockX, int a_BlockY, int a_BlockZ, cWorld * a_World)
+bool cBlockPistonHandler::CanPushBlock(
+	const Vector3i & a_BlockPos, cWorld * a_World, bool a_RequirePushable,
+	Vector3iSet & a_BlocksPushed, const Vector3i & a_PushDir
+)
 {
-	BLOCKTYPE pistonBlock;
-	NIBBLETYPE pistonMeta;
-	a_World->GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, pistonBlock, pistonMeta);
+	const static std::array<Vector3i, 6> pushingDirs =
+	{
+		{
+			Vector3i(-1,  0,  0), Vector3i(1, 0, 0),
+			Vector3i( 0, -1,  0), Vector3i(0, 1, 0),
+			Vector3i( 0,  0, -1), Vector3i(0, 0, 1)
+		}
+	};
 
-	if (IsExtended(pistonMeta))
+	BLOCKTYPE currBlock;
+	NIBBLETYPE currMeta;
+	a_World->GetBlockTypeMeta(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, currBlock, currMeta);
+
+	if (currBlock == E_BLOCK_AIR)
 	{
-		// Already extended, bail out
-		return;
+		// Air can be pushed
+		return true;
 	}
 
-	int dist = FirstPassthroughBlock(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, a_World);
-	if (dist < 0)
+	if (!a_RequirePushable && cBlockInfo::IsPistonBreakable(currBlock))
 	{
-		// FirstPassthroughBlock says piston can't push anything, bail out
-		return;
+		// Block should not be broken, when it's not in the pushing direction
+		return true;
 	}
 
-	a_World->BroadcastBlockAction(a_BlockX, a_BlockY, a_BlockZ, 0, pistonMeta, pistonBlock);
-	a_World->BroadcastSoundEffect("tile.piston.out", static_cast<double>(a_BlockX), static_cast<double>(a_BlockY), static_cast<double>(a_BlockZ), 0.5f, 0.7f);
+	if (!CanPush(currBlock, currMeta))
+	{
+		// When it's not required to push this block, don't fail
+		return !a_RequirePushable;
+	}
 
-	// Drop the breakable block in the line, if appropriate:
-	AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, dist + 1);  // "a_Block" now at the breakable / empty block
-	BLOCKTYPE currBlock;
-	NIBBLETYPE currMeta;
-	a_World->GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, currBlock, currMeta);
-	if (currBlock != E_BLOCK_AIR)
+	if (a_BlocksPushed.size() >= PISTON_MAX_PUSH_DISTANCE)
 	{
-		cBlockHandler * Handler = BlockHandler(currBlock);
-		if (Handler->DoesDropOnUnsuitable())
+		// Do not allow to push too much blocks
+		return false;
+	}
+
+	if (!a_BlocksPushed.insert(a_BlockPos).second || cBlockInfo::IsPistonBreakable(currBlock))
+	{
+		return true;  // Element exist already
+	}
+
+	if (currBlock == E_BLOCK_SLIME_BLOCK)
+	{
+		// Try to push the other directions
+		for (const auto & testDir : pushingDirs)
 		{
-			cChunkInterface ChunkInterface(a_World->GetChunkMap());
-			cBlockInServerPluginInterface PluginInterface(*a_World);
-			Handler->DropBlock(ChunkInterface, *a_World, PluginInterface, nullptr, a_BlockX, a_BlockY, a_BlockZ);
+			if (!CanPushBlock(a_BlockPos + testDir, a_World, false, a_BlocksPushed, a_PushDir))
+			{
+				// When it's not possible for a direction, then fail
+				return false;
+			}
 		}
 	}
 
-	// Push blocks, from the furthest to the nearest:
-	int oldx = a_BlockX, oldy = a_BlockY, oldz = a_BlockZ;
-	NIBBLETYPE currBlockMeta;
+	// Try to push the block in front of this block
+	return CanPushBlock(a_BlockPos + a_PushDir, a_World, true, a_BlocksPushed, a_PushDir);
+}
+
+
+
+
 
-	for (int i = dist + 1; i > 1; i--)
+void cBlockPistonHandler::ExtendPiston(Vector3i a_BlockPos, cWorld * a_World)
+{
+	BLOCKTYPE pistonBlock;
+	NIBBLETYPE pistonMeta;
+	a_World->GetBlockTypeMeta(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, pistonBlock, pistonMeta);
+
+	if (IsExtended(pistonMeta))
 	{
-		AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, -1);
-		a_World->GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, currBlock, currBlockMeta);
-		a_World->SetBlock(oldx, oldy, oldz, currBlock, currBlockMeta);
-		oldx = a_BlockX;
-		oldy = a_BlockY;
-		oldz = a_BlockZ;
+		// Already extended, bail out
+		return;
 	}
 
-	int extx = a_BlockX;
-	int exty = a_BlockY;
-	int extz = a_BlockZ;
-	AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, -1);
-	// "a_Block" now at piston body, "ext" at future extension
+	Vector3i pushDir = MetadataToOffset(pistonMeta);
 
-	a_World->SetBlock(a_BlockX, a_BlockY, a_BlockZ, pistonBlock, pistonMeta | 0x8);
-	a_World->SetBlock(extx, exty, extz, E_BLOCK_PISTON_EXTENSION, pistonMeta | (IsSticky(pistonBlock) ? 8 : 0));
+	Vector3iSet blocksPushed;
+	if (!CanPushBlock(a_BlockPos + pushDir, a_World, true, blocksPushed, pushDir))
+	{
+		// Can't push anything, bail out
+		return;
+	}
+
+	a_World->BroadcastBlockAction(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, 0, pistonMeta, pistonBlock);
+	a_World->BroadcastSoundEffect("tile.piston.out", a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, 0.5f, 0.7f);
+
+	PushBlocks(blocksPushed, a_World, pushDir);
+
+	// Set the extension and the piston base correctly
+	Vector3i extensionPos = a_BlockPos + pushDir;
+	a_World->SetBlock(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, pistonBlock, pistonMeta | 0x8);
+	a_World->SetBlock(
+		extensionPos.x, extensionPos.y, extensionPos.z,
+		E_BLOCK_PISTON_EXTENSION, pistonMeta | (IsSticky(pistonBlock) ? 8 : 0)
+	);
 }
 
 
 
 
 
-void cBlockPistonHandler::RetractPiston(int a_BlockX, int a_BlockY, int a_BlockZ, cWorld * a_World)
+void cBlockPistonHandler::RetractPiston(Vector3i a_BlockPos, cWorld * a_World)
 {
 	BLOCKTYPE pistonBlock;
 	NIBBLETYPE pistonMeta;
-	a_World->GetBlockTypeMeta(a_BlockX, a_BlockY, a_BlockZ, pistonBlock, pistonMeta);
+	a_World->GetBlockTypeMeta(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, pistonBlock, pistonMeta);
 
 	if (!IsExtended(pistonMeta))
 	{
@@ -192,39 +260,42 @@ void cBlockPistonHandler::RetractPiston(int a_BlockX, int a_BlockY, int a_BlockZ
 		return;
 	}
 
+	Vector3i pushDir = MetadataToOffset(pistonMeta);
+
 	// Check the extension:
-	AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, 1);
-	if (a_World->GetBlock(a_BlockX, a_BlockY, a_BlockZ) != E_BLOCK_PISTON_EXTENSION)
+	Vector3i extensionPos = a_BlockPos + pushDir;
+	if (a_World->GetBlock(extensionPos) != E_BLOCK_PISTON_EXTENSION)
 	{
 		LOGD("%s: Piston without an extension - still extending, or just in an invalid state?", __FUNCTION__);
 		return;
 	}
 
-	AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, -1);
-	a_World->SetBlock(a_BlockX, a_BlockY, a_BlockZ, pistonBlock, pistonMeta & ~(8));
-	a_World->BroadcastBlockAction(a_BlockX, a_BlockY, a_BlockZ, 1, pistonMeta & ~(8), pistonBlock);
-	a_World->BroadcastSoundEffect("tile.piston.in", static_cast<double>(a_BlockX), static_cast<double>(a_BlockY), static_cast<double>(a_BlockZ), 0.5f, 0.7f);
-	AddPistonDir(a_BlockX, a_BlockY, a_BlockZ, pistonMeta, 1);
+	// Remove Extension
+	a_World->SetBlock(extensionPos.x, extensionPos.y, extensionPos.z, E_BLOCK_AIR, 0);
 
-	// Retract the extension, pull block if appropriate
-	if (IsSticky(pistonBlock))
+	a_World->SetBlock(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, pistonBlock, pistonMeta & ~(8));
+	a_World->BroadcastBlockAction(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, 1, pistonMeta & ~(8), pistonBlock);
+	a_World->BroadcastSoundEffect("tile.piston.in", a_BlockPos.x, a_BlockPos.y, a_BlockPos.z, 0.5f, 0.7f);
+
+	if (!IsSticky(pistonBlock))
 	{
-		int tempx = a_BlockX, tempy = a_BlockY, tempz = a_BlockZ;
-		AddPistonDir(tempx, tempy, tempz, pistonMeta, 1);
-		BLOCKTYPE tempBlock;
-		NIBBLETYPE tempMeta;
-		a_World->GetBlockTypeMeta(tempx, tempy, tempz, tempBlock, tempMeta);
-		if (CanPull(tempBlock, tempMeta))
-		{
-			// Pull the block
-			a_World->SetBlock(a_BlockX, a_BlockY, a_BlockZ, tempBlock, tempMeta);
-			a_World->SetBlock(tempx, tempy, tempz, E_BLOCK_AIR, 0);
-			return;
-		}
+		// No need for block pulling, bail out
+		return;
+	}
+
+	// Get the block to pull
+	a_BlockPos += pushDir * 2;
+	// Try to "push" the pulling block in the opposite direction
+	pushDir *= -1;
+
+	Vector3iSet pushedBlocks;
+	if (!CanPushBlock(a_BlockPos, a_World, false, pushedBlocks, pushDir))
+	{
+		// Not pushable, bail out
+		return;
 	}
-	
-	// Retract without pulling
-	a_World->SetBlock(a_BlockX, a_BlockY, a_BlockZ, E_BLOCK_AIR, 0);
+
+	PushBlocks(pushedBlocks, a_World, pushDir);
 }
 
 
@@ -245,17 +316,16 @@ cBlockPistonHeadHandler::cBlockPistonHeadHandler(void) :
 
 void cBlockPistonHeadHandler::OnDestroyedByPlayer(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ)
 {
-	NIBBLETYPE OldMeta = a_ChunkInterface.GetBlockMeta(a_BlockX, a_BlockY, a_BlockZ);
+	Vector3i blockPos(a_BlockX, a_BlockY, a_BlockZ);
 
-	int newX = a_BlockX;
-	int newY = a_BlockY;
-	int newZ = a_BlockZ;
-	AddPistonDir(newX, newY, newZ, OldMeta, -1);
+	// Get the base of the piston
+	NIBBLETYPE OldMeta = a_ChunkInterface.GetBlockMeta(blockPos.x, blockPos.y, blockPos.z);
+	blockPos -= cBlockPistonHandler::MetadataToOffset(OldMeta);
 
-	BLOCKTYPE Block = a_ChunkInterface.GetBlock(newX, newY, newZ);
+	BLOCKTYPE Block = a_ChunkInterface.GetBlock(blockPos);
 	if ((Block == E_BLOCK_STICKY_PISTON) || (Block == E_BLOCK_PISTON))
 	{
-		a_ChunkInterface.DigBlock(a_WorldInterface, newX, newY, newZ);
+		a_ChunkInterface.DigBlock(a_WorldInterface, blockPos.x, blockPos.y, blockPos.z);
 		if (a_Player->IsGameModeCreative())
 		{
 			return;  // No pickups if creative
@@ -263,7 +333,7 @@ void cBlockPistonHeadHandler::OnDestroyedByPlayer(cChunkInterface & a_ChunkInter
 
 		cItems Pickups;
 		Pickups.push_back(cItem(Block, 1));
-		a_WorldInterface.SpawnItemPickups(Pickups, a_BlockX + 0.5, a_BlockY + 0.5, a_BlockZ + 0.5);
+		a_WorldInterface.SpawnItemPickups(Pickups, blockPos.x + 0.5, blockPos.y + 0.5, blockPos.z + 0.5);
 	}
 }