+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 4096
+
+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;
+ int ackframe; // server only: last acknowledged frame
+ vec3_t eye;
+ entity_frameinfo_t frames[MAX_ENTITY_HISTORY];
+ 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;
+ 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_UNUSED4 (1<<27)
+#define E_UNUSED5 (1<<28)
+#define E_UNUSED6 (1<<29)
+#define E_UNUSED7 (1<<30)
+#define E_EXTEND4 (1<<31)
+