added DP_ENT_GLOWMOD extension, like DP_ENT_COLORMOD but alters glow

[xonotic/darkplaces.git] / protocol.h

/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// protocol.h -- communications protocols

#ifndef PROTOCOL_H
#define PROTOCOL_H

// protocolversion_t is defined in common.h

protocolversion_t Protocol_EnumForName(const char *s);
const char *Protocol_NameForEnum(protocolversion_t p);
protocolversion_t Protocol_EnumForNumber(int n);
int Protocol_NumberForEnum(protocolversion_t p);
void Protocol_Names(char *buffer, size_t buffersize);

// model effects
#define MF_ROCKET       1                       // leave a trail
#define MF_GRENADE      2                       // leave a trail
#define MF_GIB          4                       // leave a trail
#define MF_ROTATE       8                       // rotate (bonus items)
#define MF_TRACER       16                      // green split trail
#define MF_ZOMGIB       32                      // small blood trail
#define MF_TRACER2      64                      // orange split trail + rotate
#define MF_TRACER3      128                     // purple trail

// entity effects
#define EF_BRIGHTFIELD                  1
#define EF_MUZZLEFLASH                  2
#define EF_BRIGHTLIGHT                  4
#define EF_DIMLIGHT                     8
#define EF_NODRAW                               16
#define EF_ADDITIVE                             32
#define EF_BLUE                                 64
#define EF_RED                                  128
#define EF_NOGUNBOB                             256                     // LordHavoc: when used with .viewmodelforclient this makes the entity attach to the view without gun bobbing and such effects, it also works on the player entity to disable gun bobbing of the engine-managed .viewmodel (without affecting any .viewmodelforclient entities attached to the player)
#define EF_FULLBRIGHT                   512                     // LordHavoc: fullbright
#define EF_FLAME                                1024            // LordHavoc: on fire
#define EF_STARDUST                             2048            // LordHavoc: showering sparks
#define EF_NOSHADOW                             4096            // LordHavoc: does not cast a shadow
#define EF_NODEPTHTEST                  8192            // LordHavoc: shows through walls
#define EF_SELECTABLE                   16384           // LordHavoc: highlights when PRYDON_CLIENTCURSOR mouse is over it
#define EF_DOUBLESIDED                  32768           //[515]: disable cull face for this entity
#define EF_NOSELFSHADOW                 65536           // LordHavoc: does not cast a shadow on itself (or any other EF_NOSELFSHADOW entities)
#define EF_UNUSED17                             131072
#define EF_UNUSED18                             262144
#define EF_UNUSED19                             524288
#define EF_UNUSED20                             1048576
#define EF_TELEPORT_BIT                 2097152         // div0: teleport bit (toggled when teleporting, prevents lerping when the bit has changed)
#define EF_LOWPRECISION                 4194304         // LordHavoc: entity is low precision (integer coordinates) to save network bandwidth  (serverside only)
#define EF_NOMODELFLAGS                 8388608         // indicates the model's .effects should be ignored (allows overriding them)
#define EF_ROCKET                               16777216        // leave a trail
#define EF_GRENADE                              33554432        // leave a trail
#define EF_GIB                                  67108864        // leave a trail
#define EF_ROTATE                               134217728       // rotate (bonus items)
#define EF_TRACER                               268435456       // green split trail
#define EF_ZOMGIB                               536870912       // small blood trail
#define EF_TRACER2                              1073741824      // orange split trail + rotate
#define EF_TRACER3                              0x80000000      // purple trail

// internaleffects bits (no overlap with EF_ bits):
#define INTEF_FLAG1QW                           1
#define INTEF_FLAG2QW                           2

// flags for the pflags field of entities
#define PFLAGS_NOSHADOW                 1
#define PFLAGS_CORONA                   2
#define PFLAGS_FULLDYNAMIC              128 // must be set or the light fields are ignored

// if the high bit of the servercmd is set, the low bits are fast update flags:
#define U_MOREBITS              (1<<0)
#define U_ORIGIN1               (1<<1)
#define U_ORIGIN2               (1<<2)
#define U_ORIGIN3               (1<<3)
#define U_ANGLE2                (1<<4)
// LordHavoc: U_NOLERP was only ever used for monsters, so I renamed it U_STEP
#define U_STEP                  (1<<5)
#define U_FRAME                 (1<<6)
// just differentiates from other updates
#define U_SIGNAL                (1<<7)

#define U_ANGLE1                (1<<8)
#define U_ANGLE3                (1<<9)
#define U_MODEL                 (1<<10)
#define U_COLORMAP              (1<<11)
#define U_SKIN                  (1<<12)
#define U_EFFECTS               (1<<13)
#define U_LONGENTITY    (1<<14)

// LordHavoc: protocol extension
#define U_EXTEND1               (1<<15)
// LordHavoc: first extend byte
#define U_DELTA                 (1<<16) // no data, while this is set the entity is delta compressed (uses previous frame as a baseline, meaning only things that have changed from the previous frame are sent, except for the forced full update every half second)
#define U_ALPHA                 (1<<17) // 1 byte, 0.0-1.0 maps to 0-255, not sent if exactly 1, and the entity is not sent if <=0 unless it has effects (model effects are checked as well)
#define U_SCALE                 (1<<18) // 1 byte, scale / 16 positive, not sent if 1.0
#define U_EFFECTS2              (1<<19) // 1 byte, this is .effects & 0xFF00 (second byte)
#define U_GLOWSIZE              (1<<20) // 1 byte, encoding is float/4.0, unsigned, not sent if 0
#define U_GLOWCOLOR             (1<<21) // 1 byte, palette index, default is 254 (white), this IS used for darklight (allowing colored darklight), however the particles from a darklight are always black, not sent if default value (even if glowsize or glowtrail is set)
#define U_COLORMOD              (1<<22) // 1 byte, 3 bit red, 3 bit green, 2 bit blue, this lets you tint an object artifically, so you could make a red rocket, or a blue fiend...
#define U_EXTEND2               (1<<23) // another byte to follow
// LordHavoc: second extend byte
#define U_GLOWTRAIL             (1<<24) // leaves a trail of particles (of color .glowcolor, or black if it is a negative glowsize)
#define U_VIEWMODEL             (1<<25) // attachs the model to the view (origin and angles become relative to it), only shown to owner, a more powerful alternative to .weaponmodel and such
#define U_FRAME2                (1<<26) // 1 byte, this is .frame & 0xFF00 (second byte)
#define U_MODEL2                (1<<27) // 1 byte, this is .modelindex & 0xFF00 (second byte)
#define U_EXTERIORMODEL (1<<28) // causes this model to not be drawn when using a first person view (third person will draw it, first person will not)
#define U_UNUSED29              (1<<29) // future expansion
#define U_UNUSED30              (1<<30) // future expansion
#define U_EXTEND3               (1<<31) // another byte to follow, future expansion

#define SU_VIEWHEIGHT   (1<<0)
#define SU_IDEALPITCH   (1<<1)
#define SU_PUNCH1               (1<<2)
#define SU_PUNCH2               (1<<3)
#define SU_PUNCH3               (1<<4)
#define SU_VELOCITY1    (1<<5)
#define SU_VELOCITY2    (1<<6)
#define SU_VELOCITY3    (1<<7)
//define        SU_AIMENT               (1<<8)  AVAILABLE BIT
#define SU_ITEMS                (1<<9)
#define SU_ONGROUND             (1<<10)         // no data follows, the bit is it
#define SU_INWATER              (1<<11)         // no data follows, the bit is it
#define SU_WEAPONFRAME  (1<<12)
#define SU_ARMOR                (1<<13)
#define SU_WEAPON               (1<<14)
#define SU_EXTEND1              (1<<15)
// first extend byte
#define SU_PUNCHVEC1    (1<<16)
#define SU_PUNCHVEC2    (1<<17)
#define SU_PUNCHVEC3    (1<<18)
#define SU_VIEWZOOM             (1<<19) // byte factor (0 = 0.0 (not valid), 255 = 1.0)
#define SU_UNUSED20             (1<<20)
#define SU_UNUSED21             (1<<21)
#define SU_UNUSED22             (1<<22)
#define SU_EXTEND2              (1<<23) // another byte to follow, future expansion
// second extend byte
#define SU_UNUSED24             (1<<24)
#define SU_UNUSED25             (1<<25)
#define SU_UNUSED26             (1<<26)
#define SU_UNUSED27             (1<<27)
#define SU_UNUSED28             (1<<28)
#define SU_UNUSED29             (1<<29)
#define SU_UNUSED30             (1<<30)
#define SU_EXTEND3              (1<<31) // another byte to follow, future expansion

// a sound with no channel is a local only sound
#define SND_VOLUME              (1<<0)          // a byte
#define SND_ATTENUATION (1<<1)          // a byte
#define SND_LOOPING             (1<<2)          // a long
#define SND_LARGEENTITY (1<<3)          // a short and a byte (instead of a short)
#define SND_LARGESOUND  (1<<4)          // a short (instead of a byte)


// defaults for clientinfo messages
#define DEFAULT_VIEWHEIGHT      22


// game types sent by serverinfo
// these determine which intermission screen plays
#define GAME_COOP                       0
#define GAME_DEATHMATCH         1

//==================
// note that there are some defs.qc that mirror to these numbers
// also related to svc_strings[] in cl_parse
//==================

//
// server to client
//
#define svc_bad                         0
#define svc_nop                         1
#define svc_disconnect          2
#define svc_updatestat          3       // [byte] [long]
#define svc_version                     4       // [long] server version
#define svc_setview                     5       // [short] entity number
#define svc_sound                       6       // <see code>
#define svc_time                        7       // [float] server time
#define svc_print                       8       // [string] null terminated string
#define svc_stufftext           9       // [string] stuffed into client's console buffer
                                                                // the string should be \n terminated
#define svc_setangle            10      // [angle3] set the view angle to this absolute value

#define svc_serverinfo          11      // [long] version
                                                // [string] signon string
                                                // [string]..[0]model cache
                                                // [string]...[0]sounds cache
#define svc_lightstyle          12      // [byte] [string]
#define svc_updatename          13      // [byte] [string]
#define svc_updatefrags         14      // [byte] [short]
#define svc_clientdata          15      // <shortbits + data>
#define svc_stopsound           16      // <see code>
#define svc_updatecolors        17      // [byte] [byte]
#define svc_particle            18      // [vec3] <variable>
#define svc_damage                      19

#define svc_spawnstatic         20
//      svc_spawnbinary         21
#define svc_spawnbaseline       22

#define svc_temp_entity         23

#define svc_setpause            24      // [byte] on / off
#define svc_signonnum           25      // [byte]  used for the signon sequence

#define svc_centerprint         26      // [string] to put in center of the screen

#define svc_killedmonster       27
#define svc_foundsecret         28

#define svc_spawnstaticsound    29      // [coord3] [byte] samp [byte] vol [byte] aten

#define svc_intermission        30              // [string] music
#define svc_finale                      31              // [string] music [string] text

#define svc_cdtrack                     32              // [byte] track [byte] looptrack
#define svc_sellscreen          33

#define svc_cutscene            34

#define svc_showlmp                     35              // [string] slotname [string] lmpfilename [short] x [short] y
#define svc_hidelmp                     36              // [string] slotname
#define svc_skybox                      37              // [string] skyname

// LordHavoc: my svc_ range, 50-69
#define svc_downloaddata        50              // [int] start [short] size
#define svc_updatestatubyte     51              // [byte] stat [byte] value
#define svc_effect                      52              // [vector] org [byte] modelindex [byte] startframe [byte] framecount [byte] framerate
#define svc_effect2                     53              // [vector] org [short] modelindex [short] startframe [byte] framecount [byte] framerate
#define svc_sound2                      54              // (obsolete in DP6 and later) short soundindex instead of byte
#define svc_precache            54              // [short] precacheindex [string] filename, precacheindex is + 0 for modelindex and +32768 for soundindex
#define svc_spawnbaseline2      55              // short modelindex instead of byte
#define svc_spawnstatic2        56              // short modelindex instead of byte
#define svc_entities            57              // [int] deltaframe [int] thisframe [float vector] eye [variable length] entitydata
#define svc_csqcentities        58              // [short] entnum [variable length] entitydata ... [short] 0x0000
#define svc_spawnstaticsound2   59      // [coord3] [short] samp [byte] vol [byte] aten
#define svc_trailparticles      60              // [short] entnum [short] effectnum [vector] start [vector] end
#define svc_pointparticles      61              // [short] effectnum [vector] start [vector] velocity [short] count
#define svc_pointparticles1     62              // [short] effectnum [vector] start, same as svc_pointparticles except velocity is zero and count is 1

//
// client to server
//
#define clc_bad                 0
#define clc_nop                 1
#define clc_disconnect  2
#define clc_move                3                       // [usercmd_t]
#define clc_stringcmd   4               // [string] message

// LordHavoc: my clc_ range, 50-59
#define clc_ackframe    50              // [int] framenumber
#define clc_ackdownloaddata     51      // [int] start [short] size   (note: exact echo of latest values received in svc_downloaddata, packet-loss handling is in the server)
#define clc_unusedlh2   52
#define clc_unusedlh3   53
#define clc_unusedlh4   54
#define clc_unusedlh5   55
#define clc_unusedlh6   56
#define clc_unusedlh7   57
#define clc_unusedlh8   58
#define clc_unusedlh9   59

//
// temp entity events
//
#define TE_SPIKE                        0 // [vector] origin
#define TE_SUPERSPIKE           1 // [vector] origin
#define TE_GUNSHOT                      2 // [vector] origin
#define TE_EXPLOSION            3 // [vector] origin
#define TE_TAREXPLOSION         4 // [vector] origin
#define TE_LIGHTNING1           5 // [entity] entity [vector] start [vector] end
#define TE_LIGHTNING2           6 // [entity] entity [vector] start [vector] end
#define TE_WIZSPIKE                     7 // [vector] origin
#define TE_KNIGHTSPIKE          8 // [vector] origin
#define TE_LIGHTNING3           9 // [entity] entity [vector] start [vector] end
#define TE_LAVASPLASH           10 // [vector] origin
#define TE_TELEPORT                     11 // [vector] origin
#define TE_EXPLOSION2           12 // [vector] origin [byte] startcolor [byte] colorcount

// PGM 01/21/97
#define TE_BEAM                         13 // [entity] entity [vector] start [vector] end
// PGM 01/21/97

// Nehahra effects used in the movie (TE_EXPLOSION3 also got written up in a QSG tutorial, hence it's not marked NEH)
#define TE_EXPLOSION3           16 // [vector] origin [coord] red [coord] green [coord] blue
#define TE_LIGHTNING4NEH        17 // [string] model [entity] entity [vector] start [vector] end

// LordHavoc: added some TE_ codes (block1 - 50-60)
#define TE_BLOOD                        50 // [vector] origin [byte] xvel [byte] yvel [byte] zvel [byte] count
#define TE_SPARK                        51 // [vector] origin [byte] xvel [byte] yvel [byte] zvel [byte] count
#define TE_BLOODSHOWER          52 // [vector] min [vector] max [coord] explosionspeed [short] count
#define TE_EXPLOSIONRGB         53 // [vector] origin [byte] red [byte] green [byte] blue
#define TE_PARTICLECUBE         54 // [vector] min [vector] max [vector] dir [short] count [byte] color [byte] gravity [coord] randomvel
#define TE_PARTICLERAIN         55 // [vector] min [vector] max [vector] dir [short] count [byte] color
#define TE_PARTICLESNOW         56 // [vector] min [vector] max [vector] dir [short] count [byte] color
#define TE_GUNSHOTQUAD          57 // [vector] origin
#define TE_SPIKEQUAD            58 // [vector] origin
#define TE_SUPERSPIKEQUAD       59 // [vector] origin
// LordHavoc: block2 - 70-80
#define TE_EXPLOSIONQUAD        70 // [vector] origin
#define TE_UNUSED1                      71 // unused
#define TE_SMALLFLASH           72 // [vector] origin
#define TE_CUSTOMFLASH          73 // [vector] origin [byte] radius / 8 - 1 [byte] lifetime / 256 - 1 [byte] red [byte] green [byte] blue
#define TE_FLAMEJET                     74 // [vector] origin [vector] velocity [byte] count
#define TE_PLASMABURN           75 // [vector] origin
// LordHavoc: Tei grabbed these codes
#define TE_TEI_G3                       76 // [vector] start [vector] end [vector] angles
#define TE_TEI_SMOKE            77 // [vector] origin [vector] dir [byte] count
#define TE_TEI_BIGEXPLOSION     78 // [vector] origin
#define TE_TEI_PLASMAHIT        79 // [vector} origin [vector] dir [byte] count


// these are bits for the 'flags' field of the entity_state_t
#define RENDER_STEP 1
#define RENDER_GLOWTRAIL 2
#define RENDER_VIEWMODEL 4
#define RENDER_EXTERIORMODEL 8
#define RENDER_LOWPRECISION 16 // send as low precision coordinates to save bandwidth
#define RENDER_COLORMAPPED 32
#define RENDER_SHADOW 65536 // cast shadow
#define RENDER_LIGHT 131072 // receive light
#define RENDER_NOSELFSHADOW 262144 // render lighting on this entity before its own shadow is added to the scene
// (note: all RENDER_NOSELFSHADOW entities are grouped together and rendered in a batch before their shadows are rendered, so they can not shadow eachother either)

typedef enum entity_state_active_e
{
        ACTIVE_NOT = 0,
        ACTIVE_NETWORK = 1,
        ACTIVE_SHARED = 2
}
entity_state_active_t;

// this is 96 bytes
typedef struct entity_state_s
{
        // ! means this is not sent to client
        double time; // ! time this state was built (used on client for interpolation)
        float netcenter[3]; // ! for network prioritization, this is the center of the bounding box (which may differ from the origin)
        float origin[3];
        float angles[3];
        int effects;
        unsigned int customizeentityforclient; // !
        unsigned short number; // entity number this state is for
        unsigned short modelindex;
        unsigned short frame;
        unsigned short tagentity;
        unsigned short specialvisibilityradius; // ! larger if it has effects/light
        unsigned short viewmodelforclient; // !
        unsigned short exteriormodelforclient; // ! not shown if first person viewing from this entity, shown in all other cases
        unsigned short nodrawtoclient; // !
        unsigned short drawonlytoclient; // !
        unsigned short light[4]; // color*256 (0.00 to 255.996), and radius*1
        unsigned char active; // true if a valid state
        unsigned char lightstyle;
        unsigned char lightpflags;
        unsigned char colormap;
        unsigned char skin; // also chooses cubemap for rtlights if lightpflags & LIGHTPFLAGS_FULLDYNAMIC
        unsigned char alpha;
        unsigned char scale;
        unsigned char glowsize;
        unsigned char glowcolor;
        unsigned char flags;
        unsigned char internaleffects; // INTEF_FLAG1QW and so on
        unsigned char tagindex;
        unsigned char colormod[3];
        unsigned char glowmod[3];
        // padding to a multiple of 8 bytes (to align the double time)
        unsigned char unused[2];
}
entity_state_t;

// baseline state values
extern entity_state_t defaultstate;
// reads a quake entity from the network stream
void EntityFrameQuake_ReadEntity(int bits);
// checks for stats changes and sets corresponding host_client->statsdeltabits
// (also updates host_client->stats array)
void Protocol_UpdateClientStats(const int *stats);
// writes reliable messages updating stats (not used by DP6 and later
// protocols which send updates in their WriteFrame function using a different
// method of reliable messaging)
void Protocol_WriteStatsReliable(void);
// writes a list of quake entities to the network stream
// (or as many will fit)
qboolean EntityFrameQuake_WriteFrame(sizebuf_t *msg, int maxsize, int numstates, const entity_state_t *states);
// cleans up dead entities each frame after ReadEntity (which doesn't clear unused entities)
void EntityFrameQuake_ISeeDeadEntities(void);

/*
PROTOCOL_DARKPLACES3
server updates entities according to some (unmentioned) scheme.

a frame consists of all visible entities, some of which are up to date,
often some are not up to date.

these entities are stored in a range (firstentity/endentity) of structs in the
entitydata[] buffer.

to make a commit the server performs these steps:
1. duplicate oldest frame in database (this is the baseline) as new frame, and
   write frame numbers (oldest frame's number, new frame's number) and eye
   location to network packet (eye location is obsolete and will be removed in
   future revisions)
2. write an entity change to packet and modify new frame accordingly
   (this repeats until packet is sufficiently full or new frame is complete)
3. write terminator (0xFFFF) to network packet
   (FIXME: this terminator value conflicts with MAX_EDICTS 32768...)

to read a commit the client performs these steps:
1. reads frame numbers from packet and duplicates baseline frame as new frame,
   also reads eye location but does nothing with it (obsolete).
2. delete frames older than the baseline which was used
3. read entity changes from packet until terminator (0xFFFF) is encountered,
   each change is applied to entity frame.
4. sends ack framenumber to server as part of input packet

if server receives ack message in put packet it performs these steps:
1. remove all older frames from database.
*/

/*
PROTOCOL_DARKPLACES4
a frame consists of some visible entities in a range (this is stored as start and end, note that end may be less than start if it wrapped).

these entities are stored in a range (firstentity/endentity) of structs in the entitydata[] buffer.

to make a commit the server performs these steps:
1. build an entity_frame_t using appropriate functions, containing (some of) the visible entities, this is passed to the Write function to send it.

This documention is unfinished!
the Write function performs these steps:
1. check if entity frame is larger than MAX_ENTITYFRAME or is larger than available space in database, if so the baseline is defaults, otherwise it is the current baseline of the database.
2. write differences of an entity compared to selected baseline.
3. add entity to entity update in database.
4. if there are more entities to write and packet is not full, go back to step 2.
5. write terminator (0xFFFF) as entity number.
6. return.





server updates entities in looping ranges, a frame consists of a range of visible entities (not always all visible entities),
*/

#define MAX_ENTITY_HISTORY 64
#define MAX_ENTITY_DATABASE (MAX_EDICTS * 2)

// build entity data in this, to pass to entity read/write functions
typedef struct entity_frame_s
{
        double time;
        int framenum;
        int numentities;
        int firstentitynum;
        int lastentitynum;
        vec3_t eye;
        entity_state_t entitydata[MAX_ENTITY_DATABASE];
}
entity_frame_t;

typedef struct entity_frameinfo_s
{
        double time;
        int framenum;
        int firstentity; // index into entitydata, modulo MAX_ENTITY_DATABASE
        int endentity; // index into entitydata, firstentity + numentities
}
entity_frameinfo_t;

typedef struct entityframe_database_s
{
        // note: these can be far out of range, modulo with MAX_ENTITY_DATABASE to get a valid range (which may wrap)
        // start and end of used area, when adding a new update to database, store at endpos, and increment endpos
        // when removing updates from database, nudge down frames array to only contain useful frames
        // this logic should explain better:
        // if (numframes >= MAX_ENTITY_HISTORY || (frames[numframes - 1].endentity - frames[0].firstentity) + entitiestoadd > MAX_ENTITY_DATABASE)
        //     flushdatabase();
        // note: if numframes == 0, insert at start (0 in entitydata)
        // the only reason this system is used is to avoid copying memory when frames are removed
        int numframes;
        // server only: last sent frame
        int latestframenum;
        // server only: last acknowledged frame
        int ackframenum;
        // the current state in the database
        vec3_t eye;
        // table of entities in the entityhistorydata
        entity_frameinfo_t frames[MAX_ENTITY_HISTORY];
        // entities
        entity_state_t entitydata[MAX_ENTITY_DATABASE];

        // structs for building new frames and reading them
        entity_frame_t deltaframe;
        entity_frame_t framedata;
}
entityframe_database_t;

// LordHavoc: these are in approximately sorted order, according to cost and
// likelyhood of being used for numerous objects in a frame

// note that the bytes are not written/read in this order, this is only the
// order of the bits to minimize overhead from extend bytes

// enough to describe a nail, gib, shell casing, bullet hole, or rocket
#define E_ORIGIN1               (1<<0)
#define E_ORIGIN2               (1<<1)
#define E_ORIGIN3               (1<<2)
#define E_ANGLE1                (1<<3)
#define E_ANGLE2                (1<<4)
#define E_ANGLE3                (1<<5)
#define E_MODEL1                (1<<6)
#define E_EXTEND1               (1<<7)

// enough to describe almost anything
#define E_FRAME1                (1<<8)
#define E_EFFECTS1              (1<<9)
#define E_ALPHA                 (1<<10)
#define E_SCALE                 (1<<11)
#define E_COLORMAP              (1<<12)
#define E_SKIN                  (1<<13)
#define E_FLAGS                 (1<<14)
#define E_EXTEND2               (1<<15)

// players, custom color glows, high model numbers
#define E_FRAME2                (1<<16)
#define E_MODEL2                (1<<17)
#define E_EFFECTS2              (1<<18)
#define E_GLOWSIZE              (1<<19)
#define E_GLOWCOLOR             (1<<20)
#define E_LIGHT                 (1<<21)
#define E_LIGHTPFLAGS   (1<<22)
#define E_EXTEND3               (1<<23)

#define E_SOUND1                (1<<24)
#define E_SOUNDVOL              (1<<25)
#define E_SOUNDATTEN    (1<<26)
#define E_TAGATTACHMENT (1<<27)
#define E_LIGHTSTYLE    (1<<28)
#define E_UNUSED6               (1<<29)
#define E_UNUSED7               (1<<30)
#define E_EXTEND4               (1<<31)

// returns difference between two states as E_ flags
int EntityState_DeltaBits(const entity_state_t *o, const entity_state_t *n);
// write E_ flags to a msg
void EntityState_WriteExtendBits(sizebuf_t *msg, unsigned int bits);
// write values for the E_ flagged fields to a msg
void EntityState_WriteFields(const entity_state_t *ent, sizebuf_t *msg, unsigned int bits);
// write entity number and E_ flags and their values, or a remove number, describing the change from delta to ent
void EntityState_WriteUpdate(const entity_state_t *ent, sizebuf_t *msg, const entity_state_t *delta);
// read E_ flags
int EntityState_ReadExtendBits(void);
// read values for E_ flagged fields and apply them to a state
void EntityState_ReadFields(entity_state_t *e, unsigned int bits);

// (client and server) allocates a new empty database
entityframe_database_t *EntityFrame_AllocDatabase(mempool_t *mempool);
// (client and server) frees the database
void EntityFrame_FreeDatabase(entityframe_database_t *d);
// (server) clears the database to contain no frames (thus delta compression
// compresses against nothing)
void EntityFrame_ClearDatabase(entityframe_database_t *d);
// (server and client) removes frames older than 'frame' from database
void EntityFrame_AckFrame(entityframe_database_t *d, int frame);
// (server) clears frame, to prepare for adding entities
void EntityFrame_Clear(entity_frame_t *f, vec3_t eye, int framenum);
// (server and client) reads a frame from the database
void EntityFrame_FetchFrame(entityframe_database_t *d, int framenum, entity_frame_t *f);
// (server and client) adds a entity_frame to the database, for future
// reference
void EntityFrame_AddFrame(entityframe_database_t *d, vec3_t eye, int framenum, int numentities, const entity_state_t *entitydata);
// (server) writes a frame to network stream
qboolean EntityFrame_WriteFrame(sizebuf_t *msg, int maxsize, entityframe_database_t *d, int numstates, const entity_state_t *states, int viewentnum);
// (client) reads a frame from network stream
void EntityFrame_CL_ReadFrame(void);
// (client) returns the frame number of the most recent frame recieved
int EntityFrame_MostRecentlyRecievedFrameNum(entityframe_database_t *d);

typedef struct entity_database4_commit_s
{
        // frame number this commit represents
        int framenum;
        // number of entities in entity[] array
        int numentities;
        // maximum number of entities in entity[] array (dynamic resizing)
        int maxentities;
        entity_state_t *entity;
}
entity_database4_commit_t;

typedef struct entity_database4_s
{
        // what mempool to use for allocations
        mempool_t *mempool;
        // reference frame
        int referenceframenum;
        // reference entities array is resized according to demand
        int maxreferenceentities;
        // array of states for entities, these are indexable by their entity number (yes there are gaps)
        entity_state_t *referenceentity;
        // commits waiting to be applied to the reference database when confirmed
        // (commit[i]->numentities == 0 means it is empty)
        entity_database4_commit_t commit[MAX_ENTITY_HISTORY];
        // (server only) the current commit being worked on
        entity_database4_commit_t *currentcommit;
        // (server only) if a commit won't fit entirely, continue where it left
        // off next frame
        int currententitynumber;
        // (server only)
        int latestframenumber;
}
entityframe4_database_t;

// should-be-private functions that aren't
entity_state_t *EntityFrame4_GetReferenceEntity(entityframe4_database_t *d, int number);
void EntityFrame4_AddCommitEntity(entityframe4_database_t *d, const entity_state_t *s);

// allocate a database
entityframe4_database_t *EntityFrame4_AllocDatabase(mempool_t *pool);
// free a database
void EntityFrame4_FreeDatabase(entityframe4_database_t *d);
// reset a database (resets compression but does not reallocate anything)
void EntityFrame4_ResetDatabase(entityframe4_database_t *d);
// updates database to account for a frame-received acknowledgment
int EntityFrame4_AckFrame(entityframe4_database_t *d, int framenum, int servermode);
// writes a frame to the network stream
qboolean EntityFrame4_WriteFrame(sizebuf_t *msg, int maxsize, entityframe4_database_t *d, int numstates, const entity_state_t *states);
// reads a frame from the network stream
void EntityFrame4_CL_ReadFrame(void);

// reset all entity fields (typically used if status changed)
#define E5_FULLUPDATE (1<<0)
// E5_ORIGIN32=0: short[3] = s->origin[0] * 8, s->origin[1] * 8, s->origin[2] * 8
// E5_ORIGIN32=1: float[3] = s->origin[0], s->origin[1], s->origin[2]
#define E5_ORIGIN (1<<1)
// E5_ANGLES16=0: byte[3] = s->angle[0] * 256 / 360, s->angle[1] * 256 / 360, s->angle[2] * 256 / 360
// E5_ANGLES16=1: short[3] = s->angle[0] * 65536 / 360, s->angle[1] * 65536 / 360, s->angle[2] * 65536 / 360
#define E5_ANGLES (1<<2)
// E5_MODEL16=0: byte = s->modelindex
// E5_MODEL16=1: short = s->modelindex
#define E5_MODEL (1<<3)
// E5_FRAME16=0: byte = s->frame
// E5_FRAME16=1: short = s->frame
#define E5_FRAME (1<<4)
// byte = s->skin
#define E5_SKIN (1<<5)
// E5_EFFECTS16=0 && E5_EFFECTS32=0: byte = s->effects
// E5_EFFECTS16=1 && E5_EFFECTS32=0: short = s->effects
// E5_EFFECTS16=0 && E5_EFFECTS32=1: int = s->effects
// E5_EFFECTS16=1 && E5_EFFECTS32=1: int = s->effects
#define E5_EFFECTS (1<<6)
// bits >= (1<<8)
#define E5_EXTEND1 (1<<7)

// byte = s->renderflags
#define E5_FLAGS (1<<8)
// byte = bound(0, s->alpha * 255, 255)
#define E5_ALPHA (1<<9)
// byte = bound(0, s->scale * 16, 255)
#define E5_SCALE (1<<10)
// flag
#define E5_ORIGIN32 (1<<11)
// flag
#define E5_ANGLES16 (1<<12)
// flag
#define E5_MODEL16 (1<<13)
// byte = s->colormap
#define E5_COLORMAP (1<<14)
// bits >= (1<<16)
#define E5_EXTEND2 (1<<15)

// short = s->tagentity
// byte = s->tagindex
#define E5_ATTACHMENT (1<<16)
// short[4] = s->light[0], s->light[1], s->light[2], s->light[3]
// byte = s->lightstyle
// byte = s->lightpflags
#define E5_LIGHT (1<<17)
// byte = s->glowsize
// byte = s->glowcolor
#define E5_GLOW (1<<18)
// short = s->effects
#define E5_EFFECTS16 (1<<19)
// int = s->effects
#define E5_EFFECTS32 (1<<20)
// flag
#define E5_FRAME16 (1<<21)
// byte[3] = s->colormod[0], s->colormod[1], s->colormod[2]
#define E5_COLORMOD (1<<22)
// bits >= (1<<24)
#define E5_EXTEND3 (1<<23)

// byte[3] = s->glowmod[0], s->glowmod[1], s->glowmod[2]
#define E5_GLOWMOD (1<<24)
// unused
#define E5_UNUSED25 (1<<25)
// unused
#define E5_UNUSED26 (1<<26)
// unused
#define E5_UNUSED27 (1<<27)
// unused
#define E5_UNUSED28 (1<<28)
// unused
#define E5_UNUSED29 (1<<29)
// unused
#define E5_UNUSED30 (1<<30)
// bits2 > 0
#define E5_EXTEND4 (1<<31)

#define ENTITYFRAME5_MAXPACKETLOGS 64
#define ENTITYFRAME5_MAXSTATES 1024
#define ENTITYFRAME5_PRIORITYLEVELS 32

typedef struct entityframe5_changestate_s
{
        unsigned int number;
        unsigned int bits;
}
entityframe5_changestate_t;

typedef struct entityframe5_packetlog_s
{
        int packetnumber;
        int numstates;
        entityframe5_changestate_t states[ENTITYFRAME5_MAXSTATES];
        unsigned char statsdeltabits[(MAX_CL_STATS+7)/8];
}
entityframe5_packetlog_t;

typedef struct entityframe5_database_s
{
        // number of the latest message sent to client
        int latestframenum;
        // updated by WriteFrame for internal use
        int viewentnum;

        // logs of all recently sent messages (between acked and latest)
        entityframe5_packetlog_t packetlog[ENTITYFRAME5_MAXPACKETLOGS];

        // this goes up as needed and causes all the arrays to be reallocated
        int maxedicts;

        // which properties of each entity have changed since last send
        int *deltabits; // [maxedicts]
        // priorities of entities (updated whenever deltabits change)
        // (derived from deltabits)
        unsigned char *priorities; // [maxedicts]
        // last frame this entity was sent on, for prioritzation
        int *updateframenum; // [maxedicts]

        // database of current status of all entities
        entity_state_t *states; // [maxedicts]
        // which entities are currently active
        // (duplicate of the active bit of every state in states[])
        // (derived from states)
        unsigned char *visiblebits; // [(maxedicts+7)/8]

        // old notes

        // this is used to decide which changestates to set each frame
        //int numvisiblestates;
        //entity_state_t visiblestates[MAX_EDICTS];

        // sorted changing states that need to be sent to the client
        // kept sorted in lowest to highest priority order, because this allows
        // the numchangestates to simply be decremented whenever an state is sent,
        // rather than a memmove to remove them from the start.
        //int numchangestates;
        //entityframe5_changestate_t changestates[MAX_EDICTS];

        // buffers for building priority info
        int prioritychaincounts[ENTITYFRAME5_PRIORITYLEVELS];
        unsigned short prioritychains[ENTITYFRAME5_PRIORITYLEVELS][ENTITYFRAME5_MAXSTATES];
}
entityframe5_database_t;

entityframe5_database_t *EntityFrame5_AllocDatabase(mempool_t *pool);
void EntityFrame5_FreeDatabase(entityframe5_database_t *d);
void EntityState5_WriteUpdate(int number, const entity_state_t *s, int changedbits, sizebuf_t *msg);
int EntityState5_DeltaBitsForState(entity_state_t *o, entity_state_t *n);
void EntityFrame5_CL_ReadFrame(void);
void EntityFrame5_LostFrame(entityframe5_database_t *d, int framenum);
void EntityFrame5_AckFrame(entityframe5_database_t *d, int framenum);
qboolean EntityFrame5_WriteFrame(sizebuf_t *msg, int maxsize, entityframe5_database_t *d, int numstates, const entity_state_t *states, int viewentnum, int movesequence, qboolean need_empty);

extern cvar_t developer_networkentities;

// QUAKEWORLD
// server to client
#define qw_svc_bad                              0
#define qw_svc_nop                              1
#define qw_svc_disconnect               2
#define qw_svc_updatestat               3       // [byte] [byte]
#define qw_svc_setview                  5       // [short] entity number
#define qw_svc_sound                    6       // <see code>
#define qw_svc_print                    8       // [byte] id [string] null terminated string
#define qw_svc_stufftext                9       // [string] stuffed into client's console buffer
#define qw_svc_setangle                 10      // [angle3] set the view angle to this absolute value
#define qw_svc_serverdata               11      // [long] protocol ...
#define qw_svc_lightstyle               12      // [byte] [string]
#define qw_svc_updatefrags              14      // [byte] [short]
#define qw_svc_stopsound                16      // <see code>
#define qw_svc_damage                   19
#define qw_svc_spawnstatic              20
#define qw_svc_spawnbaseline    22
#define qw_svc_temp_entity              23      // variable
#define qw_svc_setpause                 24      // [byte] on / off
#define qw_svc_centerprint              26      // [string] to put in center of the screen
#define qw_svc_killedmonster    27
#define qw_svc_foundsecret              28
#define qw_svc_spawnstaticsound 29      // [coord3] [byte] samp [byte] vol [byte] aten
#define qw_svc_intermission             30              // [vec3_t] origin [vec3_t] angle
#define qw_svc_finale                   31              // [string] text
#define qw_svc_cdtrack                  32              // [byte] track
#define qw_svc_sellscreen               33
#define qw_svc_smallkick                34              // set client punchangle to 2
#define qw_svc_bigkick                  35              // set client punchangle to 4
#define qw_svc_updateping               36              // [byte] [short]
#define qw_svc_updateentertime  37              // [byte] [float]
#define qw_svc_updatestatlong   38              // [byte] [long]
#define qw_svc_muzzleflash              39              // [short] entity
#define qw_svc_updateuserinfo   40              // [byte] slot [long] uid
#define qw_svc_download                 41              // [short] size [size bytes]
#define qw_svc_playerinfo               42              // variable
#define qw_svc_nails                    43              // [byte] num [48 bits] xyzpy 12 12 12 4 8
#define qw_svc_chokecount               44              // [byte] packets choked
#define qw_svc_modellist                45              // [strings]
#define qw_svc_soundlist                46              // [strings]
#define qw_svc_packetentities   47              // [...]
#define qw_svc_deltapacketentities      48              // [...]
#define qw_svc_maxspeed                 49              // maxspeed change, for prediction
#define qw_svc_entgravity               50              // gravity change, for prediction
#define qw_svc_setinfo                  51              // setinfo on a client
#define qw_svc_serverinfo               52              // serverinfo
#define qw_svc_updatepl                 53              // [byte] [byte]
// QUAKEWORLD
// client to server
#define qw_clc_bad                      0
#define qw_clc_nop                      1
#define qw_clc_move                     3               // [[usercmd_t]
#define qw_clc_stringcmd        4               // [string] message
#define qw_clc_delta            5               // [byte] sequence number, requests delta compression of message
#define qw_clc_tmove            6               // teleport request, spectator only
#define qw_clc_upload           7               // teleport request, spectator only
// QUAKEWORLD
// playerinfo flags from server
// playerinfo always sends: playernum, flags, origin[] and framenumber
#define QW_PF_MSEC                      (1<<0)
#define QW_PF_COMMAND           (1<<1)
#define QW_PF_VELOCITY1 (1<<2)
#define QW_PF_VELOCITY2 (1<<3)
#define QW_PF_VELOCITY3 (1<<4)
#define QW_PF_MODEL             (1<<5)
#define QW_PF_SKINNUM           (1<<6)
#define QW_PF_EFFECTS           (1<<7)
#define QW_PF_WEAPONFRAME       (1<<8)          // only sent for view player
#define QW_PF_DEAD                      (1<<9)          // don't block movement any more
#define QW_PF_GIB                       (1<<10)         // offset the view height differently
#define QW_PF_NOGRAV            (1<<11)         // don't apply gravity for prediction
// QUAKEWORLD
// if the high bit of the client to server byte is set, the low bits are
// client move cmd bits
// ms and angle2 are allways sent, the others are optional
#define QW_CM_ANGLE1    (1<<0)
#define QW_CM_ANGLE3    (1<<1)
#define QW_CM_FORWARD   (1<<2)
#define QW_CM_SIDE              (1<<3)
#define QW_CM_UP                (1<<4)
#define QW_CM_BUTTONS   (1<<5)
#define QW_CM_IMPULSE   (1<<6)
#define QW_CM_ANGLE2    (1<<7)
// QUAKEWORLD
// the first 16 bits of a packetentities update holds 9 bits
// of entity number and 7 bits of flags
#define QW_U_ORIGIN1    (1<<9)
#define QW_U_ORIGIN2    (1<<10)
#define QW_U_ORIGIN3    (1<<11)
#define QW_U_ANGLE2             (1<<12)
#define QW_U_FRAME              (1<<13)
#define QW_U_REMOVE             (1<<14)         // REMOVE this entity, don't add it
#define QW_U_MOREBITS   (1<<15)
// if MOREBITS is set, these additional flags are read in next
#define QW_U_ANGLE1             (1<<0)
#define QW_U_ANGLE3             (1<<1)
#define QW_U_MODEL              (1<<2)
#define QW_U_COLORMAP   (1<<3)
#define QW_U_SKIN               (1<<4)
#define QW_U_EFFECTS    (1<<5)
#define QW_U_SOLID              (1<<6)          // the entity should be solid for prediction
// QUAKEWORLD
// temp entity events
#define QW_TE_SPIKE                             0
#define QW_TE_SUPERSPIKE                1
#define QW_TE_GUNSHOT                   2
#define QW_TE_EXPLOSION                 3
#define QW_TE_TAREXPLOSION              4
#define QW_TE_LIGHTNING1                5
#define QW_TE_LIGHTNING2                6
#define QW_TE_WIZSPIKE                  7
#define QW_TE_KNIGHTSPIKE               8
#define QW_TE_LIGHTNING3                9
#define QW_TE_LAVASPLASH                10
#define QW_TE_TELEPORT                  11
#define QW_TE_BLOOD                             12
#define QW_TE_LIGHTNINGBLOOD    13
// QUAKEWORLD
// effect flags
#define QW_EF_BRIGHTFIELD               1
#define QW_EF_MUZZLEFLASH               2
#define QW_EF_BRIGHTLIGHT               4
#define QW_EF_DIMLIGHT                  8
#define QW_EF_FLAG1                             16
#define QW_EF_FLAG2                             32
#define QW_EF_BLUE                              64
#define QW_EF_RED                               128

#define QW_UPDATE_BACKUP 64
#define QW_UPDATE_MASK (QW_UPDATE_BACKUP - 1)
#define QW_MAX_PACKET_ENTITIES 64

// note: QW stats are directly compatible with NQ
// (but FRAGS, WEAPONFRAME, and VIEWHEIGHT are unused)
// so these defines are not actually used by darkplaces, but kept for reference
#define QW_STAT_HEALTH                  0
//#define QW_STAT_FRAGS                 1
#define QW_STAT_WEAPON                  2
#define QW_STAT_AMMO                    3
#define QW_STAT_ARMOR                   4
//#define QW_STAT_WEAPONFRAME           5
#define QW_STAT_SHELLS                  6
#define QW_STAT_NAILS                   7
#define QW_STAT_ROCKETS                 8
#define QW_STAT_CELLS                   9
#define QW_STAT_ACTIVEWEAPON    10
#define QW_STAT_TOTALSECRETS    11
#define QW_STAT_TOTALMONSTERS   12
#define QW_STAT_SECRETS                 13 // bumped on client side by svc_foundsecret
#define QW_STAT_MONSTERS                14 // bumped by svc_killedmonster
#define QW_STAT_ITEMS                   15
//#define QW_STAT_VIEWHEIGHT            16

// build entity data in this, to pass to entity read/write functions
typedef struct entityframeqw_snapshot_s
{
        double time;
        qboolean invalid;
        int num_entities;
        entity_state_t entities[QW_MAX_PACKET_ENTITIES];
}
entityframeqw_snapshot_t;

typedef struct entityframeqw_database_s
{
        entityframeqw_snapshot_t snapshot[QW_UPDATE_BACKUP];
}
entityframeqw_database_t;

entityframeqw_database_t *EntityFrameQW_AllocDatabase(mempool_t *pool);
void EntityFrameQW_FreeDatabase(entityframeqw_database_t *d);
void EntityStateQW_ReadPlayerUpdate(void);
void EntityFrameQW_CL_ReadFrame(qboolean delta);

struct client_s;
void EntityFrameCSQC_LostFrame(struct client_s *client, int framenum);
qboolean EntityFrameCSQC_WriteFrame (sizebuf_t *msg, int maxsize, int numnumbers, const unsigned short *numbers, int framenum);

#endif