mcserver/source/Blocks/BlockHandler.h

#pragma once

#include "../Defines.h"
#include "../Item.h"
#include "../Chunk.h"





// fwd:
class cWorld;
class cPlayer;





class cBlockHandler
{
public:
	cBlockHandler(BLOCKTYPE a_BlockType);

	/// Called when the block gets ticked either by a random tick or by a queued tick
	virtual void OnUpdate(cWorld *a_World, int a_BlockX, int a_BlockY, int a_BlockZ);

	/** Called before a block is placed	into a world. 
	The handler should return true to allow placement, false to refuse.
	Also, the handler should set a_BlockType and a_BlockMeta to correct values for the newly placed block.
	Called by cItemHandler::GetPlacementBlockTypeMeta() if the item is a block
	*/
	virtual bool GetPlacementBlockTypeMeta(
		cWorld * a_World, cPlayer * a_Player,
		int a_BlockX, int a_BlockY, int a_BlockZ, char a_BlockFace, 
		int a_CursorX, int a_CursorY, int a_CursorZ,
		BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta
	);

	/// Called by cWorld::SetBlock() after the block has been set
	virtual void OnPlaced(cWorld * a_World, int a_BlockX, int a_BlockY, int a_BlockZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
	
	/// Called by cClientHandle::HandlePlaceBlock() after the player has placed a new block. Called after OnPlaced().
	virtual void OnPlacedByPlayer(
		cWorld * a_World, cPlayer * a_Player, 
		int a_BlockX, int a_BlockY, int a_BlockZ, char a_BlockFace, 
		int a_CursorX, int a_CursorY, int a_CursorZ,
		BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta
	);
	
	/// Called before the player has destroyed a block
	virtual void OnDestroyedByPlayer(cWorld * a_World, cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Called before a block gets destroyed / replaced with air
	virtual void OnDestroyed(cWorld * a_World, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Called when a direct neighbor of this block has been changed (The position is the own position, not the neighbor position)
	virtual void OnNeighborChanged(cWorld * a_World, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Notifies all neighbors of the given block about a change
	static void NeighborChanged(cWorld * a_World, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Called while the player diggs the block.
	virtual void OnDigging(cWorld * a_World, cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Called if the user right clicks the block and the block is useable
	virtual void OnUse(cWorld * a_World, cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ, char a_BlockFace, int a_CursorX, int a_CursorY, int a_CursorZ);
	
	/// Called when the item is mined to convert it into pickups. Pickups may specify multiple items.
	virtual void ConvertToPickups(cItems & a_Pickups, NIBBLETYPE a_BlockMeta);
	
	/// Handles the dropping of a block based on what ConvertToDrops() returns. This will not destroy the block. a_Digger is the entity causing the drop; it may be NULL
	virtual void DropBlock(cWorld * a_World, cEntity * a_Digger, int a_BlockX, int a_BlockY, int a_BlockZ);
	
	/// Returns step sound name of block
	virtual const char * GetStepSound(void);
	
	/// Checks if the block can stay at the specified relative coords in the chunk
	virtual bool CanBeAt(int a_RelX, int a_RelY, int a_RelZ, const cChunk & a_Chunk);
	
	/** Checks if the block can be placed at this point.
	Default: CanBeAt(...) 
	NOTE: This call doesn't actually place the block
	*/
	// virtual bool CanBePlacedAt(cWorld * a_World, int a_BlockX, int a_BlockY, int a_BlockZ, char a_Dir);
	
	/// Called when the player tries to place a block on top of this block (Only if he aims directly on this block); return false to disallow
	virtual bool DoesAllowBlockOnTop(void);
	
	/// Called to check whether this block supports a rclk action. If it returns true, OnUse() is called
	virtual bool IsUseable(void);
	
	/** Indicates whether the client will click through this block. 
	For example digging a fire will hit the block below the fire so fire is clicked through
	*/
	virtual bool IsClickedThrough(void);
	
	/** Checks if the player can build "inside" this block. 
	For example blocks placed "on" snow will be placed at the same position. So: Snow ignores Build collision
	*/
	virtual bool DoesIgnoreBuildCollision(void);
	
	/// Indicates this block can be placed on the side of other blocks. Default: true
	virtual bool CanBePlacedOnSide(void);

	/// Does this block drop if it gets destroyed by an unsuitable situation? Default: true
	virtual bool DoesDropOnUnsuitable(void);
	
	/** Called when one of the neighbors gets set; equivalent to MC block update. 
	By default drops if position no more suitable (CanBeAt(), DoesDropOnUnsuitable(), Drop()),
	and wakes up all simulators on the block.
	*/
	virtual void Check(int a_RelX, int a_RelY, int a_RelZ, cChunk & a_Chunk);
	
	/// Returns the meta for a block after rotating it counter-clockwise from the specified meta. Default: no change
	virtual NIBBLETYPE MetaRotateCCW(NIBBLETYPE a_Meta) { return a_Meta; }
	
	/// Returns the meta for a block after rotating it clockwise from the specified meta. Default: no change
	virtual NIBBLETYPE MetaRotateCW(NIBBLETYPE a_Meta) { return a_Meta; }
	
	/// Returns the meta for a block after mirroring it around the XY plane. Default: no change
	virtual NIBBLETYPE MetaMirrorXY(NIBBLETYPE a_Meta) { return a_Meta; }

	/// Returns the meta for a block after mirroring it around the XZ plane. Default: no change
	virtual NIBBLETYPE MetaMirrorXZ(NIBBLETYPE a_Meta) { return a_Meta; }

	/// Returns the meta for a block after mirroring it around the YZ plane. Default: no change
	virtual NIBBLETYPE MetaMirrorYZ(NIBBLETYPE a_Meta) { return a_Meta; }


	/// Get the blockhandler for a specific block id
	static cBlockHandler * GetBlockHandler(BLOCKTYPE a_BlockType);

	/// Deletes all initialised block handlers
	static void Deinit();
	
protected:
	BLOCKTYPE m_BlockType;
	
	// Creates a new blockhandler for the given block type. For internal use only, use ::GetBlockHandler() instead.
	static cBlockHandler *CreateBlockHandler(BLOCKTYPE a_BlockType);
	static cBlockHandler *m_BlockHandler[256];
	static bool m_HandlerInitialized;	//used to detect if the blockhandlers are initialized
};





// Shortcut to get the blockhandler for a specific block
inline cBlockHandler * BlockHandler(BLOCKTYPE a_BlockType)
{
	return cBlockHandler::GetBlockHandler(a_BlockType);
}