Taken from John Carmack's .plan 
by PiRaMidA, 0:20 EST on Thursday, September 25th.

 //
 // qfiles.h: quake file formats
 // This file must be identical in the quake and utils directories
 //

 /*
 ========================================================================

 .MD2 triangle model file format

 ========================================================================
 */

 #define IDALIASHEADER (('2'<<24)+('P'<<16)+('D'<<8)+'I')
 #define ALIAS_VERSION 8

 #define MAX_TRIANGLES 4096
 #define MAX_VERTS 2048
 #define MAX_FRAMES 512
 #define MAX_MD2SKINS 32
 #define MAX_SKINNAME 64

 typedef struct
 {
 short s;
 short t;
 } dstvert_t;

 typedef struct 
 {
 short index_xyz[3];
 short index_st[3];
 } dtriangle_t;

 typedef struct
 {
 byte v[3]; // scaled byte to fit in frame mins/maxs
 byte lightnormalindex;
 } dtrivertx_t;

 #define DTRIVERTX_V0 0
 #define DTRIVERTX_V1 1
 #define DTRIVERTX_V2 2
 #define DTRIVERTX_LNI 3
 #define DTRIVERTX_SIZE 4

 typedef struct
 {
 float scale[3]; // multiply byte verts by this
 float translate[3]; // then add this
 char name[16]; // frame name from grabbing
 dtrivertx_t verts[1]; // variable sized
 } daliasframe_t;


 // the glcmd format:
 // a positive integer starts a tristrip command, followed by that many
 // vertex structures.
 // a negative integer starts a trifan command, followed by -x vertexes
 // a zero indicates the end of the command list.
 // a vertex consists of a floating point s, a floating point t,
 // and an integer vertex index.


 typedef struct
 {
 int ident;
 int version;

 int skinwidth;
 int skinheight;
 int framesize; // byte size of each frame

 int num_skins;
 int num_xyz;
 int num_st; // greater than num_xyz for seams
 int num_tris;
 int num_glcmds; // dwords in strip/fan command list
 int num_frames;

 int ofs_skins; // each skin is a MAX_SKINNAME string
 int ofs_st; // byte offset from start for stverts
 int ofs_tris; // offset for dtriangles
 int ofs_frames; // offset for first frame
 int ofs_glcmds; 
 int ofs_end; // end of file

 } dmdl_t;

 /*
 ========================================================================

 .SP2 sprite file format

 ========================================================================
 */

 #define IDSPRITEHEADER (('2'<<24)+('S'<<16)+('D'<<8)+'I')
 // little-endian "IDS2"
 #define SPRITE_VERSION 2

 typedef struct
 {
 int width, height;
 int origin_x, origin_y; // raster coordinates inside pic
 char name[MAX_SKINNAME]; // name of pcx file
 } dsprframe_t;

 typedef struct {
 int ident;
 int version;
 int numframes;
 dsprframe_t frames[1]; // variable sized
 } dsprite_t;

 /*
 ==============================================================================

 .WAL texture file format

 ==============================================================================
 */


 #define MIPLEVELS 4
 typedef struct miptex_s
 {
 char name[32];
 unsigned width, height;
 unsigned offsets[MIPLEVELS]; // four mip maps stored
 char animname[32]; // next frame in animation chain
 int flags;
 int contents;
 int value;
 } miptex_t;



 /*
 ==============================================================================

 .BSP file format

 ==============================================================================
 */

 #define IDBSPHEADER (('P'<<24)+('S'<<16)+('B'<<8)+'I')
 // little-endian "IBSP"

 #define BSPVERSION 38


 // upper design bounds
 // leaffaces, leafbrushes, planes, and verts are still bounded by
 // 16 bit short limits
 #define MAX_MAP_MODELS 1024
 #define MAX_MAP_BRUSHES 8192
 #define MAX_MAP_ENTITIES 2048
 #define MAX_MAP_ENTSTRING 0x20000
 #define MAX_MAP_TEXINFO 8192

 #define MAX_MAP_AREAS 256
 #define MAX_MAP_AREAPORTALS 1024
 #define MAX_MAP_PLANES 65536
 #define MAX_MAP_NODES 65536
 #define MAX_MAP_BRUSHSIDES 65536
 #define MAX_MAP_LEAFS 65536
 #define MAX_MAP_VERTS 65536
 #define MAX_MAP_FACES 65536
 #define MAX_MAP_LEAFFACES 65536
 #define MAX_MAP_LEAFBRUSHES 65536
 #define MAX_MAP_PORTALS 65536
 #define MAX_MAP_EDGES 128000
 #define MAX_MAP_SURFEDGES 256000
 #define MAX_MAP_LIGHTING 0x200000
 #define MAX_MAP_VISIBILITY 0x100000

 // key / value pair sizes

 #define MAX_KEY 32
 #define MAX_VALUE 1024

 //=============================================================================

 typedef struct
 {
 int fileofs, filelen;
 } lump_t;

 #define LUMP_ENTITIES 0
 #define LUMP_PLANES 1
 #define LUMP_VERTEXES 2
 #define LUMP_VISIBILITY 3
 #define LUMP_NODES 4
 #define LUMP_TEXINFO 5
 #define LUMP_FACES 6
 #define LUMP_LIGHTING 7
 #define LUMP_LEAFS 8
 #define LUMP_LEAFFACES 9
 #define LUMP_LEAFBRUSHES 10
 #define LUMP_EDGES 11
 #define LUMP_SURFEDGES 12
 #define LUMP_MODELS 13
 #define LUMP_BRUSHES 14
 #define LUMP_BRUSHSIDES 15
 #define LUMP_POP 16
 #define LUMP_AREAS 17
 #define LUMP_AREAPORTALS 18
 #define HEADER_LUMPS 19

 typedef struct
 {
 int ident;
 int version; 
 lump_t lumps[HEADER_LUMPS];
 } dheader_t;

 typedef struct
 {
 float mins[3], maxs[3];
 float origin[3]; // for sounds or lights
 int headnode;
 int firstface, numfaces; // submodels just draw faces
 // without walking the bsp tree
 } dmodel_t;


 typedef struct
 {
 float point[3];
 } dvertex_t;


 // 0-2 are axial planes
 #define PLANE_X 0
 #define PLANE_Y 1
 #define PLANE_Z 2

 // 3-5 are non-axial planes snapped to the nearest
 #define PLANE_ANYX 3
 #define PLANE_ANYY 4
 #define PLANE_ANYZ 5

 // planes (x&~1) and (x&~1)+1 are allways opposites

 typedef struct
 {
 float normal[3];
 float dist;
 int type; // PLANE_X - PLANE_ANYZ ?remove? trivial to regenerate
 } dplane_t;


 // contents flags are seperate bits
 // a given brush can contribute multiple content bits
 // multiple brushes can be in a single leaf

 // lower bits are stronger, and will eat weaker brushes completely
 #define CONTENTS_SOLID 1 // an eye is never valid in a solid
 #define CONTENTS_WINDOW 2 // translucent, but not watery
 #define CONTENTS_AUX 4
 #define CONTENTS_LAVA 8
 #define CONTENTS_SLIME 16
 #define CONTENTS_WATER 32
 #define CONTENTS_MIST 64
 #define LAST_VISIBLE_CONTENTS 64

 // remaining contents are non-visible, and don't eat brushes

 #define CONTENTS_AREAPORTAL 0x8000

 #define CONTENTS_PLAYERCLIP 0x10000
 #define CONTENTS_MONSTERCLIP 0x20000

 // currents can be added to any other contents, and may be mixed
 #define CONTENTS_CURRENT_0 0x40000
 #define CONTENTS_CURRENT_90 0x80000
 #define CONTENTS_CURRENT_180 0x100000
 #define CONTENTS_CURRENT_270 0x200000
 #define CONTENTS_CURRENT_UP 0x400000
 #define CONTENTS_CURRENT_DOWN 0x800000

 #define CONTENTS_ORIGIN 0x1000000 // removed before bsping an entity

 #define CONTENTS_MONSTER 0x2000000 // should never be on a brush, only in game
 #define CONTENTS_DEADMONSTER 0x4000000
 #define CONTENTS_DETAIL 0x8000000 // brushes to be added after vis leafs
 #define CONTENTS_TRANSLUCENT 0x10000000 // auto set if any surface has trans
 #define CONTENTS_LADDER 0x20000000


 typedef struct
 {
 int planenum;
 int children[2]; // negative numbers are -(leafs+1), not nodes
 short mins[3]; // for frustom culling
 short maxs[3];
 unsigned short firstface;
 unsigned short numfaces; // counting both sides
 } dnode_t;


 typedef struct texinfo_s
 {
 float vecs[2][4]; // [s/t][xyz offset]
 int flags; // miptex flags + overrides
 int value; // light emission, etc
 char texture[32]; // texture name (textures/*.wal)
 int nexttexinfo; // for animations, -1 = end of chain
 } texinfo_t;


 #define SURF_LIGHT 0x1 // value will hold the light strength

 #define SURF_SLICK 0x2 // effects game physics

 #define SURF_SKY 0x4 // don't draw, but add to skybox
 #define SURF_WARP 0x8 // turbulent water warp
 #define SURF_TRANS33 0x10
 #define SURF_TRANS66 0x20
 #define SURF_FLOWING 0x40 // scroll towards angle
 #define SURF_NODRAW 0x80 // don't bother referencing the texture


 // note that edge 0 is never used, because negative edge nums are used for
 // counterclockwise use of the edge in a face
 typedef struct
 {
 unsigned short v[2]; // vertex numbers
 } dedge_t;

 #define MAXLIGHTMAPS 4
 typedef struct
 {
 unsigned short planenum;
 short side;

 int firstedge; // we must support > 64k edges
 short numedges; 
 short texinfo;

 // lighting info
 byte styles[MAXLIGHTMAPS];
 int lightofs; // start of [numstyles*surfsize] samples
 } dface_t;

 typedef struct
 {
 int contents; // OR of all brushes (not needed?)

 short cluster;
 short area;

 short mins[3]; // for frustum culling
 short maxs[3];

 unsigned short firstleafface;
 unsigned short numleaffaces;

 unsigned short firstleafbrush;
 unsigned short numleafbrushes;
 } dleaf_t;

 typedef struct
 {
 unsigned short planenum; // facing out of the leaf
 short texinfo;
 } dbrushside_t;

 typedef struct
 {
 int firstside;
 int numsides;
 int contents;
 } dbrush_t;

 #define ANGLE_UP -1
 #define ANGLE_DOWN -2


 // the visibility lump consists of a header with a count, then
 // byte offsets for the PVS and PHS of each cluster, then the raw
 // compressed bit vectors
 #define DVIS_PVS 0
 #define DVIS_PHS 1
 typedef struct
 {
 int numclusters;
 int bitofs[8][2]; // bitofs[numclusters][2]
 } dvis_t;

 // each area has a list of portals that lead into other areas
 // when portals are closed, other areas may not be visible or
 // hearable even if the vis info says that it should be
 typedef struct
 {
 int portalnum;
 int otherarea;
 } dareaportal_t;

 typedef struct
 {
 int numareaportals;
 int firstareaportal;
 } darea_t;
