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
0b0010 		Is checked pretty often and has some effect on rendering. Maybe search for an WDT having this value.
0b0100 		Decides whether to use _env terrain shaders or not: funky
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;
void * somedata;

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.somedata) )
   AsyncFileReadWait( *(Main.somedata) );

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, the MWMO chunk is empty and there is no MODF chunk. For a global-WMO-only world, these chunks specify an object in the same format as it is already done in ADT files. See the ADT format description for details.

MWMO chunk

• List of filenames for WMOs (world map objects) that appear in this map tile. A contiguous block of zero-terminated strings.

MODF chunk

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

Offset 	Type 		Description
0x00 	uint32 		ID (index in the MWMO list)
0x04 	uint32 		unique identifier for this instance
0x08 	3*floats 	Position (X,Y,Z)
0x14 	3*floats 	Orientation (A,B,C)
0x20 	6*floats 	Extents
0x38 	uint32 		Flags
0x3A 	uint16 		Doodad set index
0x3C 	uint32 		Name set

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*/  UINT32 flags;		
/*03Ch*/  UINT16 doodadSet;
/*03Eh*/  UINT16 nameSet;
/*040h*/ 
};