From 7b0787d3008f86e6c90f092565ceccf9f9584e03 Mon Sep 17 00:00:00 2001
From: Noah Metzger <chomenor@gmail.com>
Date: Fri, 17 Jan 2025 17:56:54 -0600
Subject: [PATCH] server: delta snapshot developer print fix

Add deltaActive client variable to indicate whether delta snapshots are enabled, instead of relying on whether deltaMessage value is in range. Allows developer prints to correctly distinguish between delta being disabled intentionally versus by PACKET_BACKUP limit.
---
 code/server/server.h      |  3 ++-
 code/server/sv_client.c   | 11 ++++-------
 code/server/sv_snapshot.c |  9 ++-------
 3 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/code/server/server.h b/code/server/server.h
index d096f685f..c35374a30 100644
--- a/code/server/server.h
+++ b/code/server/server.h
@@ -191,7 +191,8 @@ typedef struct client_s {
 	qboolean		downloadEOF;		// We have sent the EOF block
 	int				downloadSendTime;	// time we last got an ack from the client
 
-	int				deltaMessage;		// frame last client usercmd message
+	qboolean		deltaActive;		// delta snapshots enabled
+	int				deltaMessage;		// message to create delta snapshot from
 	int				lastPacketTime;		// svs.time when packet was last received
 	int				lastConnectTime;	// svs.time when connection started
 	int				lastDisconnectTime;
diff --git a/code/server/sv_client.c b/code/server/sv_client.c
index 5e8458cd7..0c0e3afba 100644
--- a/code/server/sv_client.c
+++ b/code/server/sv_client.c
@@ -1167,7 +1167,7 @@ void SV_ClientEnterWorld( client_t *client ) {
 	ent->s.number = clientNum;
 	client->gentity = ent;
 
-	client->deltaMessage = client->netchan.outgoingSequence - (PACKET_BACKUP + 1); // force delta reset
+	client->deltaActive = qfalse;
 	client->lastSnapshotTime = svs.time - 9999; // generate a snapshot immediately
 
 	// call the game begin function
@@ -2135,11 +2135,8 @@ static void SV_UserMove( client_t *cl, msg_t *msg, qboolean delta ) {
 	usercmd_t	cmds[MAX_PACKET_USERCMDS], *cmd;
 	const usercmd_t *oldcmd;
 
-	if ( delta ) {
-		cl->deltaMessage = cl->messageAcknowledge;
-	} else {
-		cl->deltaMessage = cl->netchan.outgoingSequence - ( PACKET_BACKUP + 1 ); // force delta reset
-	}
+	cl->deltaActive = delta;
+	cl->deltaMessage = cl->messageAcknowledge;
 
 	cmdCount = MSG_ReadByte( msg );
 
@@ -2194,7 +2191,7 @@ static void SV_UserMove( client_t *cl, msg_t *msg, qboolean delta ) {
 	}
 
 	if ( cl->state != CS_ACTIVE ) {
-		cl->deltaMessage = cl->netchan.outgoingSequence - ( PACKET_BACKUP + 1 ); // force delta reset
+		cl->deltaActive = qfalse;
 		return;
 	}
 
diff --git a/code/server/sv_snapshot.c b/code/server/sv_snapshot.c
index e790ab259..3b5a054a1 100644
--- a/code/server/sv_snapshot.c
+++ b/code/server/sv_snapshot.c
@@ -129,17 +129,12 @@ static void SV_WriteSnapshotToClient( const client_t *client, msg_t *msg ) {
 	frame = &client->frames[ client->netchan.outgoingSequence & PACKET_MASK ];
 
 	// try to use a previous frame as the source for delta compressing the snapshot
-	if ( /* client->deltaMessage <= 0 || */ client->state != CS_ACTIVE ) {
-		// client is asking for a retransmit
+	if ( !client->deltaActive || client->state != CS_ACTIVE ) {
 		oldframe = NULL;
 		lastframe = 0;
 	} else if ( client->netchan.outgoingSequence - client->deltaMessage >= (PACKET_BACKUP - 3) ) {
 		// client hasn't gotten a good message through in a long time
-		if ( com_developer->integer ) {
-			if ( client->deltaMessage != client->netchan.outgoingSequence - ( PACKET_BACKUP + 1 ) ) {
-				Com_Printf( "%s: Delta request from out of date packet.\n", client->name );
-			}
-		}
+		Com_DPrintf( "%s: Delta request from out of date packet.\n", client->name );
 		oldframe = NULL;
 		lastframe = 0;
 	} else {