+#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 64 // cast shadow
+
+typedef struct
+{
+ double time; // time this state was built
+ vec3_t origin;
+ vec3_t angles;
+ int number; // entity number this state is for
+ unsigned short active; // true if a valid state
+ unsigned short modelindex;
+ unsigned short frame;
+ unsigned short effects;
+ unsigned short tagentity;
+ unsigned short specialvisibilityradius;
+ unsigned short viewmodelforclient;
+ unsigned short exteriormodelforclient;
+ unsigned short nodrawtoclient;
+ unsigned short drawonlytoclient;
+ qbyte colormap;
+ qbyte skin;
+ qbyte alpha;
+ qbyte scale;
+ qbyte glowsize;
+ qbyte glowcolor;
+ qbyte flags;
+ qbyte tagindex;
+}
+entity_state_t;
+
+/*
+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+ location to network packet (eye location is obsolete and will be removed in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),
+*/
+
+typedef struct
+{
+ double time;
+ int framenum;
+ int firstentity; // index into entitydata, modulo MAX_ENTITY_DATABASE
+ int endentity; // index into entitydata, firstentity + numentities
+}
+entity_frameinfo_t;
+
+#define MAX_ENTITY_HISTORY 64
+#define MAX_ENTITY_DATABASE (MAX_EDICTS * 2)
+
+typedef struct
+{
+ // 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 acknowledged frame
+ int ackframe;
+ // 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];
+}
+entity_database_t;
+
+// build entity data in this, to pass to entity read/write functions
+typedef struct
+{
+ double time;
+ int framenum;
+ int numentities;
+ int firstentitynum;
+ int lastentitynum;
+ vec3_t eye;
+ entity_state_t entitydata[MAX_ENTITY_DATABASE];
+}
+entity_frame_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_UNUSED1 (1<<21)
+#define E_UNUSED2 (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_UNUSED5 (1<<28)
+#define E_UNUSED6 (1<<29)
+#define E_UNUSED7 (1<<30)
+#define E_EXTEND4 (1<<31)
+
+// clears a state to baseline values
+void ClearStateToDefault(entity_state_t *s);
+// used by some of the DP protocols
+void EntityState_Write(entity_state_t *ent, sizebuf_t *msg, entity_state_t *delta);
+
+// (server) clears the database to contain no frames (thus delta compression
+// compresses against nothing)
+void EntityFrame_ClearDatabase(entity_database_t *d);
+// (server and client) removes frames older than 'frame' from database
+void EntityFrame_AckFrame(entity_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) adds an entity to frame
+void EntityFrame_AddEntity(entity_frame_t *f, entity_state_t *s);
+// (server and client) reads a frame from the database
+void EntityFrame_FetchFrame(entity_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(entity_database_t *d, entity_frame_t *f);
+// (server) writes a frame to network stream
+void EntityFrame_Write(entity_database_t *d, entity_frame_t *f, sizebuf_t *msg);
+// (client) reads a frame from network stream
+void EntityFrame_Read(entity_database_t *d);
+// (client) returns the frame number of the most recent frame recieved
+int EntityFrame_MostRecentlyRecievedFrameNum(entity_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;
+ // (client only) most recently received frame number to be sent in next
+ // input update
+ int ackframenum;
+}
+entity_database4_t;
+
+// should-be-private functions that aren't
+int EntityFrame4_SV_ChooseCommitToReplace(entity_database4_t *d);
+entity_state_t *EntityFrame4_GetReferenceEntity(entity_database4_t *d, int number);
+void EntityFrame4_AddCommitEntity(entity_database4_t *d, entity_state_t *s);
+
+// allocate a database
+entity_database4_t *EntityFrame4_AllocDatabase(mempool_t *pool);
+// free a database
+void EntityFrame4_FreeDatabase(entity_database4_t *d);
+// reset a database (resets compression but does not reallocate anything)
+void EntityFrame4_ResetDatabase(entity_database4_t *d);
+// updates database to account for a frame-received acknowledgment
+void EntityFrame4_AckFrame(entity_database4_t *d, int framenum);
+
+// begin writing a frame
+void EntityFrame4_SV_WriteFrame_Begin(entity_database4_t *d, sizebuf_t *msg, int framenum);
+// write an entity in the frame
+// returns false if full
+int EntityFrame4_SV_WriteFrame_Entity(entity_database4_t *d, sizebuf_t *msg, int maxbytes, entity_state_t *s);
+// end writing a frame
+void EntityFrame4_SV_WriteFrame_End(entity_database4_t *d, sizebuf_t *msg);
+
+// reads a frame from the network stream
+void EntityFrame4_CL_ReadFrame(entity_database4_t *d);
+
+#endif
+