Remove PVS data from demo format, derive during playback

Stop recording currentOrigin, absmin, absmax, linked per entity
(44 bytes per moving entity per frame). During playback, G_RunFrame
computes currentOrigin via BG_EvaluateTrajectory and calls
trap_LinkEntity to register in BSP for PVS.

svFlags still recorded (1-bit change flag + 4 bytes when changed).
Entity linking moved from SVD_ReadFrame (server, no trajectory eval)
to G_RunFrame demo mode (game module, has BG_EvaluateTrajectory).

Scan all MAX_GENTITIES during playback since recorded entities may
have indices above level.num_entities (game-module-spawned count).

Demo format bumped to v3. Significant file size reduction.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

code/game/g_main.c

@@ -1792,6 +1792,27 @@ int start, end;
 			}
 		}
 
+		// evaluate trajectories and link all recorded entities for PVS.
+		// SVD_ReadFrame injected entityState_t but didn't link because
+		// the server doesn't have BG_EvaluateTrajectory.
+		// scan up to MAX_GENTITIES because recorded entities may exceed
+		// level.num_entities (which only counts game-module-spawned entities).
+		for ( i = 0; i < MAX_GENTITIES; i++ ) {
+			ent = &g_entities[i];
+			if ( ent->s.eType == 0 && !ent->inuse ) {
+				continue;
+			}
+			// skip spectator slot
+			if ( ent->client && ent->client->pers.connected == CON_CONNECTED
+				 && ent->client->sess.sessionTeam == TEAM_SPECTATOR ) {
+				continue;
+			}
+			// compute currentOrigin from trajectory
+			BG_EvaluateTrajectory( &ent->s.pos, level.time, ent->r.currentOrigin );
+			ent->r.linked = qtrue;
+			trap_LinkEntity( ent );
+		}
+
 		// update rankings so follow mode can cycle through players
 		CalculateRanks();
 

code/server/sv_netdemo.c

@@ -51,7 +51,7 @@ snapshot pipeline delivers them to a spectator client.
 //
 
 #define SVDEMO_MAGIC		(('S') | ('V' << 8) | ('D' << 16) | ('M' << 24))
-#define SVDEMO_VERSION		2		// v2: optional LZ4 compression
+#define SVDEMO_VERSION		3		// v3: removed PVS data, svFlags only
 #define SVDEMO_MAX_MAPNAME	64
 
 // header flags
@@ -61,14 +61,10 @@ snapshot pipeline delivers them to a spectator client.
 //  State
 // ---------------------------------------------------------------
 
-// per-entity data stored for delta compression (entityState + PVS fields)
+// per-entity data stored for delta compression
 typedef struct {
 	entityState_t	es;
 	int				svFlags;
-	qboolean		linked;
-	vec3_t			currentOrigin;
-	vec3_t			absmin;
-	vec3_t			absmax;
 	qboolean		active;			// was this entity present last frame?
 } svdEntityState_t;
 
@@ -275,38 +271,17 @@ static void SVD_WriteFrame( fileHandle_t f ) {
 			}
 			MSG_WriteDeltaEntity( &msg, from, &ent->s, qtrue );
 
-			// write PVS fields only if changed from previous frame
+			// write svFlags only if changed (rarely changes)
-			{
+			if ( ent->r.svFlags != demo.prevEntities[i].svFlags ) {
-				qboolean pvsChanged = !demo.prevEntities[i].active
+				MSG_WriteBits( &msg, 1, 1 );
-					|| ent->r.svFlags != demo.prevEntities[i].svFlags
+				MSG_WriteLong( &msg, ent->r.svFlags );
-					|| ent->r.linked != demo.prevEntities[i].linked
+			} else {
-					|| !VectorCompare( ent->r.currentOrigin, demo.prevEntities[i].currentOrigin )
+				MSG_WriteBits( &msg, 0, 1 );
-					|| !VectorCompare( ent->r.absmin, demo.prevEntities[i].absmin )
-					|| !VectorCompare( ent->r.absmax, demo.prevEntities[i].absmax );
-
-				MSG_WriteBits( &msg, pvsChanged, 1 );
-				if ( pvsChanged ) {
-					MSG_WriteLong( &msg, ent->r.svFlags );
-					MSG_WriteLong( &msg, ent->r.linked );
-					MSG_WriteFloat( &msg, ent->r.currentOrigin[0] );
-					MSG_WriteFloat( &msg, ent->r.currentOrigin[1] );
-					MSG_WriteFloat( &msg, ent->r.currentOrigin[2] );
-					MSG_WriteFloat( &msg, ent->r.absmin[0] );
-					MSG_WriteFloat( &msg, ent->r.absmin[1] );
-					MSG_WriteFloat( &msg, ent->r.absmin[2] );
-					MSG_WriteFloat( &msg, ent->r.absmax[0] );
-					MSG_WriteFloat( &msg, ent->r.absmax[1] );
-					MSG_WriteFloat( &msg, ent->r.absmax[2] );
-				}
 			}
 
 			// update prev state
 			demo.prevEntities[i].es = ent->s;
 			demo.prevEntities[i].svFlags = ent->r.svFlags;
-			demo.prevEntities[i].linked = ent->r.linked;
-			VectorCopy( ent->r.currentOrigin, demo.prevEntities[i].currentOrigin );
-			VectorCopy( ent->r.absmin, demo.prevEntities[i].absmin );
-			VectorCopy( ent->r.absmax, demo.prevEntities[i].absmax );
 			demo.prevEntities[i].active = qtrue;
 		} else if ( demo.prevEntities[i].active ) {
 			// entity was removed — write a remove marker
@@ -734,40 +709,20 @@ static qboolean SVD_ReadFrame( fileHandle_t f ) {
 			continue;
 		}
 
-		// read PVS fields
+		// read svFlags
-		{
+		if ( MSG_ReadBits( &msg, 1 ) ) {
-			qboolean pvsChanged = MSG_ReadBits( &msg, 1 );
+			demo.playPrevEntities[entNum].svFlags = MSG_ReadLong( &msg );
-			if ( pvsChanged ) {
-				demo.playPrevEntities[entNum].svFlags = MSG_ReadLong( &msg );
-				demo.playPrevEntities[entNum].linked = MSG_ReadLong( &msg );
-				demo.playPrevEntities[entNum].currentOrigin[0] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].currentOrigin[1] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].currentOrigin[2] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmin[0] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmin[1] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmin[2] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmax[0] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmax[1] = MSG_ReadFloat( &msg );
-				demo.playPrevEntities[entNum].absmax[2] = MSG_ReadFloat( &msg );
-			}
 		}
 
 		demo.playPrevEntities[entNum].es = newEs;
 		demo.playPrevEntities[entNum].active = qtrue;
 
-		// apply to server entity
+		// apply to server entity (entity linking done in G_RunFrame
+		// which has BG_EvaluateTrajectory for computing currentOrigin)
 		ent = SV_GentityNum( entNum );
 		ent->s = newEs;
 		ent->s.number = entNum;
 		ent->r.svFlags = demo.playPrevEntities[entNum].svFlags;
-		ent->r.linked = demo.playPrevEntities[entNum].linked;
-		VectorCopy( demo.playPrevEntities[entNum].currentOrigin, ent->r.currentOrigin );
-		VectorCopy( demo.playPrevEntities[entNum].absmin, ent->r.absmin );
-		VectorCopy( demo.playPrevEntities[entNum].absmax, ent->r.absmax );
-
-		if ( ent->r.linked ) {
-			SV_LinkEntity( ent );
-		}
 
 		if ( entNum + 1 > sv.num_entities ) {
 			sv.num_entities = entNum + 1;