WDT

WDT files specify exactly which map tiles are present in a world, if any, and can also reference a "global" WMO. They have a chunked file structure.

MPHD chunk

Contains 8 32-bit integers.

uint32 flags;
uint32 something;
uint32 unused[6];

These are the only flags checked:

Flag 		Description
0b0001 		No Terrain/no terraincollision. The other flags are ONLY for ADT based maps! See a list here.
0b0010 		Use vertex shading (ADT.MCNK.MCCV)
0b0100 		Decides whether to use _env terrain shaders or not: funky and if MCAL has 4096 instead of 2048(?)
0b1000 		Disables something. No idea what. Another rendering thing. Someone may check all them in wild life..

if ( WDT_MPHD & 8 )
   return result;

The second integer is not ignored but stores something too:

for( int i = 0; i < WDT_MPHD.something/8; i++ )
{
   WDT_MAIN[i].flags = 0;
   WDT_MAIN[i].somedata = 0;
}

The other bytes seem to be unused from what I can tell.

MAIN chunk

• Map tile table.

Contains 64x64 = 4096 records of 8 bytes each.

int32 flags;
AsyncObject * asyncobject;

Flags&1 tells us, if a tile is holding an ADT. Flags&2 gets set ingame when an ADT is loaded at that position. The pointer to some data is set if the tile is loaded asynchronous.

if ( !(MAIN.flags & 2) )
   LoadADTByPosition( x, y );
if ( *(MAIN.asyncobject) )
   AsyncFileReadWait( *(MAIN.asyncobject) );

Blizzard was just too lazy to compress the files here. A simple bool array and adding the fields when parsing would the alternative. We just need to know the &1 flag.

MWMO, MODF chunks

For worlds with terrain, parsing ends here. If it has none, there is one MWMO and one MODF chunk here. The MODF chunk is limited to one entry. See the ADT format description for details.

MWMO chunk

• Filename for WMO (world map objects) that appear in this map. A zero-terminated string.

MODF chunk

• Placement information for WMOs. 64 bytes per WMO instance.

Offset 	Type 		Description
0x00 	uint32 		ID (index in the MWID list)
0x04 	uint32 		unique identifier for this instance
0x08 	3 floats 	Position (X,Y,Z)
0x14 	3 floats 	Orientation (A,B,C)
0x20 	3 floats 	Upper Extents
0x2C 	3 floats 	Lower Extents
0x38 	uint16 		Flags
0x3A    uint16          Doodad set index
0x3C 	uint16 		Name set?
0x3E 	uint16 		Padding

struct SMMapObjDef // 03-29-2005 By ObscuR
{
/*000h*/  UINT32 nameId;		
/*004h*/  UINT32 uniqueId;		
/*008h*/  float pos[3];
/*00Ch*/  		
/*010h*/  		
/*014h*/  float rot[3];
/*018h*/  	
/*01Ch*/  		
/*020h*/  float extents[6];
/*024h*/  	 
/*028h*/   	
/*02Ch*/ 	
/*030h*/ 		
/*034h*/  		
/*038h*/  UINT16 flags;
/*03Ah*/  UINT16 doodadSetIndex;
/*03Ch*/  UINT16 nameSet;		
/*03Eh*/  UINT16 pad; 
};