typedef unsigned char u_char;
typedef unsigned short u_short;
typedef unsigned long u_long;

typedef struct
{
    short x;
    short y;
    short z;
} vector_t;

typedef struct
{
    short vertices[4]; //indexes to some vertices
    short texture; //object texture #
} face4_t; //rectangle

typedef struct
{
    short vertices[3]; //indexes to some vertices
    short texture; //object texture #
} face3_t; //triangle

//offset 0
long version; //version of the .phd file, must be 0x20 for tr1

typedef struct
{
    u_char tile[256*256];
} textile_t;

//offset 0x4 - this is the same in all .phd files
long numtextiles;
textile_t textiles[numtextiles];

typedef struct
{
    short something;    //don't mess with this something :)
    short tile;         //texture tile #
    u_char something;   //maybe blurring, like with sprites?
    u_char ulx;         //upper left corner x
    u_char something;
    u_char uly;         //upper left corner y
    u_char something;
    u_char urx;         //upper right corner x
    u_char something;
    u_char ury;         //upper right corner y
    u_char something;
    u_char lrx;         //lower right corner x
    u_char something;
    u_char lry;         //lower right corner y
    u_char something;
    u_char llx;         //lower left corner x
    u_char something;
    u_char lly;         //lower left corner y
} objtexture_t;

//offset 0x31fb8 in title.phd
long numobjtextures;
objtexture_t objtextures[numobjtextures];

typedef struct
{
    short tile;         //texture tile #
    u_char ulx;         //upper left corner x
    u_char uly;         //upper left corner y
    u_char something;   //might have something to do with blurring the texture
    u_char lrx;         //lower right corner x
    u_char something;   //0 = blurry
    u_char lry;         //lower right corner y
    //the modify numbers stretch or shrink the texture by pixels from the
    //modify side, + = shrink, - = stretch
    short leftmodify;
    short topmodify;
    short rightmodify;
    short bottommodify;
} spritetexture_t;

//offset 0x321c4 in title.phd
long numspritetextures;
spritetexture_t spritetextures[numspritetextures];

Definiton: Rooms are all of the physical structures in the level.

Note: Rooms are pretty complicated, but they are the most essential part needed to create levels for Tomb Raider, so they will be given top priority.

Note: Everything in this section relates to level2.phd from the first Tomb Raider demo. Since rooms are not totally understood, I will list file offsets to the things I have some idea about.

Note: If I refer to the "first room", I am talking about the room that you push the block through to get to the area with the gold and silver keys (it is the first room in level2.phd).

There seems to be 7 different data areas for each room (from the misc. section). I can identify 4 areas (sort of), and I will create separate sections for each one once they are more understood.

Here are the areas I have identified, the names may not be the same as used by Tomb Raider. Most of this is speculative, with little or no complete testing.

-room texture vertices
-faces (indices to vertices)
-visibility info?
-room walls (solid parts)

Definiton: Room textures are used to define which textures are rendered at what position for a room. They do not contain actual graphical data. Room textures contain references to the Object textures, and not the texture tiles themselves.

typedef struct
{
    vector_t vector;
    u_char something;
    u_char colormap; //colormap # for this vertex
} rtvertex_t;

//offset 0xd0022 in level2.phd
short numroomtexturevertices;
roomtexurevertex_t roomtexturevertices[numroomtexturevertices];
short numrectangles;
face4_t rectangles[numrectangles];
short numtriangles; //this may be incorrect
face3_t triangles[numtriangles]; //this may be incorrect

Definiton: The meshes are 3D objects that aren't physically part of the level like Lara, enemies, doors?, all of the spinning objects in title.phd, etc. The mesh vertices extend from the 0, 0, 0 point of the mesh.

Note: 3D objects are constructed using geometric primitives. Usually they are triangles, but the meshes seem to use rectangles. Keep in mind that they might use more than one primitive like the room textures do.

typedef struct
{
    long something;
    short something;
    long something;
    short numvertices;
    vector_t vertices[numvertices];
    short numsomethings;
    vector_t something[numsomethings]; //this has something to do with
                                       //lighting, may not be correct
    short numrectangles;
    face4_t rectangles[numrectangles];
} mesh_t;

//offset 0x301fc in title.phd
long meshdatasize;
u_char meshdata[meshdatasize*2];

meshdata contains mesh_t structures. See the mesh pointers
section for offsets to each mesh.

//offset 0x3178c in title.phd
long nummeshpointers;
long meshpointers[nummeshpointers];

typedef struct
{
    long something;
    short nummeshes;
    short firstmesh; //first mesh number
    u_char something[10];
} meshinfo_t;

//offset 0x31f44 in title.phd
long nummeshinfos;
meshinfo_t meshinfos[nummeshinfos];

The bones seem to be VERY complicated, so it will probably be awhile before
they are understood (if ever).

typedef struct
{
    u_char red;
    u_char green;
    u_char blue;
} rgbtriple;

//offset 0x328b4 in title.phd
rgbtriple palette[256];

typedef struct
{
    u_char colormap[256];
} colormap_t;

//offset 0x32c28 in title.phd
colormap_t colormaps[34]; //34 may not be actual number

//offset 0x34e70 in title.phd
long cbsampledata; //size of all the sound samples, in bytes
u_char sampledata[cbsampledata]; //sample data (.WAV files), sound offset 0 here

typedef struct
{
    short soundsample;  //number of sample to be played for this sound info
    short volume;       //maximum volume = 0x7fff (can't be negative)
    short something;    //these may be channel or priority related
    short something;
} soundinfo_t;

//offset 0x34e2c in title.phd
long numsoundinfos;
soundinfo_t soundinfos[numsoundinfos];

//offset 0x4d2c6 in title.phd
long numsamples; //number of sound samples
long sampleoffsets[numsounds]; //offset to each sample

Sprite Textures
Object Textures
Mesh Pointers
Meshes
Anims
Structs
Ranges
Commands
Bones
Frames
Room Textures
Room Infos
Room Mesh
Room Door
Room Floor
Room Lights
Room Static
Mesh Infos
Floor Data
ITEMS!!
Cameras
Boxes
Overlaps
GroundZone
FlyZone
Animating Texture Ranges
Cinematic Frames
LoadDemo Buffer
SaveDemo Buffer
Cinematic Effects
Mummy Head Turn
Extra Door stuff
Effects_Array
Creature Data
Creature LOT
Sample Infos
Samples
Sample Offsets
Rolling Ball Stuff

- Added Room textures section
- Updated Mesh stuff section
- Updated Room stuff section
- some more cosmetic changes

- minor update to Room stuff section

- Added History section :)
- Added Bones section
- Updated Room stuff section
- a few cosmetic changes