Doomwad::Blockmap Class Reference

Inheritance diagram for Doomwad::Blockmap:

List of all members.

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Detailed Description

BLOCKMAP map resource.

See also:

Linedef Linedefs Map Thing Things WadEntry

BLOCKMAP helps to optimize collision detection calculations. It divides the level into 128 pixel squares, and records which Linedefs are in each block. Then, when the engine needs to detect if two objects collide, it consults the BLOCKMAP to see if it should perform the calculation. This way, the engine does not need to calculate every Thing and Linedef against each other every gametic, an O(2ⁿ) operation.

Header:
16 bit x-coordinate of grid origin.
16 bit y-coordinate of grid origin.
16 bit number of columns.
16 bit number of rows.

Offsets:
16 bit offset to block n.
Repeat (rows*columns) times.

Blocklists:
16 bit 0x0000.
16 bits for each Linedef in the block.
16 bit 0xFFFF.

Definition at line 90 of file blockmap.hpp.

Public Member Functions
	Blockmap (const Lump &) throw ()
	Construct from a Lump.
	Blockmap (void) throw ()
	Default constructor.
virtual bool	setFromLump (const Lump &lump) throw ()
	Convert a Lump to this entry.
virtual Lump	toLump (void) const throw ()
	Convert this entry to a Lump.
virtual std::string	toString (void) const throw ()
	Convert this entry to a std::string.
virtual	~Blockmap (void) throw ()
	Destructor.
Static Public Attributes
static const std::string	NAME = "BLOCKMAP"
	Name of a Blockmap entry.

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Constructor & Destructor Documentation

Blockmap::Blockmap (  const Lump &  lump  )  throw ()

Construct from a Lump. Constructs a Blockmap object given raw Lump data. Parameters: lump  Source Lump from which to pull blockmap data. Definition at line 64 of file blockmap.cpp. References setFromLump().

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Member Function Documentation

bool Blockmap::setFromLump (  const Lump &  lump  )  throw () [virtual]

Convert a Lump to this entry. Lumps should not know about specific data structures. Those structures know about Lumps, including how to convert from them. Setting from a Lump involves parsing that Lump's contents to see if they are valid. If they are, then this object will contain what you expect it to. If not, it will return false and the atomic operation will not succeed. Parameters: lump  Reference to a source Lump object. Returns: True if successful, false if not. Implements Doomwad::WadEntry. Definition at line 78 of file blockmap.cpp. Referenced by Blockmap().

Lump Blockmap::toLump (  void   )  const throw () [virtual]

Convert this entry to a Lump. Each subclass must be able to convert itself to a Lump for storage in a Wad. Returns: Lump containing the raw file representation of this entry. Implements Doomwad::WadEntry. Definition at line 85 of file blockmap.cpp. References NAME.

std::string Blockmap::toString (  void   )  const throw () [virtual]

Convert this entry to a std::string. The exact implementation varies by the exact concrete class, but the idea is to convert the entry into a summary to be displayed to the user. Please note that converting to a string may lose information. This is not serialization in the purest sense of the word, this is merely a quick and dirty user-readable summary of the entry. True serialization is achieved by converting a Lump object and using its stream I/O functions to read and write. Returns: std::string containing a summary of this entry. Implements Doomwad::WadEntry. Definition at line 93 of file blockmap.cpp.

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