- In conjunction with all the below changes, attempt to fix A_CheckSightOrRange and A_CheckSight

for multiplayer: They now always check through the eyes of every player. For players whose
  cameras are not players, they also check through the eyes of those cameras.
- Using spynext/spyprev to switch from a non-player to a player now writes a command to the
  network stream and lets Net_DoCommand() take care of it later. The logic here is that if
  a player is viewing from something that isn't another player, then every player needs to know
  about it for sync purposes. Consequently, when they stop viewing from a non-player and switch
  to a player, everybody needs to know about that too. But if they are viewing from a
  player, it doesn't matter which player it is, so they can spynext/spyprev all they want
  without letting the other players know about it (and without potentially breaking demos--due
  to the above-mentioned two codepointers--while doing it during demo playback).
- Replaced the instances of checking players[consoleplayer].camera for a valid pointer to
  ones that do it for every player.
- Fixed: Upon changing levels, all players but the consoleplayer would have their cameras NULLed.
- Fixed: player_t::FixPointers() needs to bypass the read barriers, or it won't be able to
  do substitutions of old objects that are pending deletion.

SVN r3448 (trunk)

src/d_net.cpp

@@ -592,13 +592,16 @@ void PlayerIsGone (int netnode, int netconsole)
 		Printf ("%s left the game\n", players[netconsole].userinfo.netname);
 	}
 
-	// [RH] Revert to your own view if spying through the player who left
-	if (players[consoleplayer].camera == players[netconsole].mo)
+	// [RH] Revert each player to their own view if spying through the player who left
+	for (int ii = 0; ii < MAXPLAYERS; ++ii)
 	{
-		players[consoleplayer].camera = players[consoleplayer].mo;
-		if (StatusBar != NULL)
+		if (playeringame[ii] && players[ii].camera == players[netconsole].mo)
 		{
-			StatusBar->AttachToPlayer (&players[consoleplayer]);
+			players[ii].camera = players[ii].mo;
+			if (ii == consoleplayer && StatusBar != NULL)
+			{
+				StatusBar->AttachToPlayer (&players[ii]);
+			}
 		}
 	}
 
@@ -2460,6 +2463,10 @@ void Net_DoCommand (int type, BYTE **stream, int player)
 		F_AdvanceIntermission();
 		break;
 
+	case DEM_REVERTCAMERA:
+		players[player].camera = players[player].mo;
+		break;
+
 	default:
 		I_Error ("Unknown net command: %d", type);
 		break;

src/d_protocol.h

@@ -162,6 +162,7 @@ enum EDemoCommand
 	DEM_SETPITCHLIMIT,	// 63 Byte: Up limit, Byte: Down limit (in degrees)
 	DEM_ADVANCEINTER,	// 64 Advance intermission screen state
 	DEM_RUNNAMEDSCRIPT,	// 65 String: Script name, Byte: Arg count + Always flag; each arg is a 4-byte int
+	DEM_REVERTCAMERA,	// 66
 };
 
 // The following are implemented by cht_DoCheat in m_cheat.cpp

src/g_game.cpp

@@ -831,7 +831,12 @@ static void ChangeSpy (bool forward)
 	// If not viewing through a player, return your eyes to your own head.
 	if (players[consoleplayer].camera->player == NULL)
 	{
-		players[consoleplayer].camera = players[consoleplayer].mo;
+		// When watching demos, you will just have to wait until your player
+		// has done this for you, since it could desync otherwise.
+		if (!demoplayback)
+		{
+			Net_WriteByte(DEM_REVERTCAMERA);
+		}
 		return;
 	}
 

src/g_level.cpp

@@ -920,10 +920,13 @@ void G_DoLoadLevel (int position, bool autosave)
 	level.starttime = gametic;
 	G_UnSnapshotLevel (!savegamerestore);	// [RH] Restore the state of the level.
 	G_FinishTravel ();
-	if (players[consoleplayer].camera == NULL ||
-		players[consoleplayer].camera->player != NULL)
-	{ // If we are viewing through a player, make sure it is us.
-        players[consoleplayer].camera = players[consoleplayer].mo;
+	// For each player, if they are viewing through a player, make sure it is themselves.
+	for (int ii = 0; i < MAXPLAYERS; ++i)
+	{
+		if (playeringame[ii] && (players[ii].camera == NULL || players[ii].camera->player != NULL))
+		{
+			players[ii].camera = players[ii].mo;
+		}
 	}
 	StatusBar->AttachToPlayer (&players[consoleplayer]);
 	P_DoDeferedScripts ();	// [RH] Do script actions that were triggered on another map.
@@ -1143,6 +1146,7 @@ void G_FinishTravel ()
 			pawn->target = NULL;
 			pawn->lastenemy = NULL;
 			pawn->player->mo = pawn;
+			pawn->player->camera = pawn;
 			DObject::StaticPointerSubstitution (oldpawn, pawn);
 			oldpawn->Destroy();
 			pawndup->Destroy ();

src/p_mobj.cpp

@@ -4051,9 +4051,12 @@ APlayerPawn *P_SpawnPlayer (FMapThing *mthing, bool tempplayer)
 
 	p->velx = p->vely = 0;		// killough 10/98: initialize bobbing to 0.
 
-	if (players[consoleplayer].camera == oldactor)
+	for (int ii = 0; ii < MAXPLAYERS; ++ii)
 	{
-		players[consoleplayer].camera = mobj;
+		if (playeringame[ii] && players[ii].camera == oldactor)
+		{
+			players[ii].camera = oldactor;
+		}
 	}
 
 	// [RH] Allow chasecam for demo watching

src/p_user.cpp

@@ -326,21 +326,25 @@ size_t player_t::FixPointers (const DObject *old, DObject *rep)
 {
 	APlayerPawn *replacement = static_cast<APlayerPawn *>(rep);
 	size_t changed = 0;
-	if (mo == old)				mo = replacement, changed++;
-	if (poisoner == old)		poisoner = replacement, changed++;
-	if (attacker == old)		attacker = replacement, changed++;
-	if (camera == old)			camera = replacement, changed++;
-	if (dest == old)			dest = replacement, changed++;
-	if (prev == old)			prev = replacement, changed++;
-	if (enemy == old)			enemy = replacement, changed++;
-	if (missile == old)			missile = replacement, changed++;
-	if (mate == old)			mate = replacement, changed++;
-	if (last_mate == old)		last_mate = replacement, changed++;
-	if (ReadyWeapon == old)		ReadyWeapon = static_cast<AWeapon *>(rep), changed++;
-	if (PendingWeapon == old)	PendingWeapon = static_cast<AWeapon *>(rep), changed++;
-	if (PremorphWeapon == old)	PremorphWeapon = static_cast<AWeapon *>(rep), changed++;
-	if (ConversationNPC == old)	ConversationNPC = replacement, changed++;
-	if (ConversationPC == old)	ConversationPC = replacement, changed++;
+
+	// The construct *& is used in several of these to avoid the read barriers
+	// that would turn the pointer we want to check to NULL if the old object
+	// is pending deletion.
+	if (mo == old)					mo = replacement, changed++;
+	if (*&poisoner == old)			poisoner = replacement, changed++;
+	if (*&attacker == old)			attacker = replacement, changed++;
+	if (*&camera == old)			camera = replacement, changed++;
+	if (*&dest == old)				dest = replacement, changed++;
+	if (*&prev == old)				prev = replacement, changed++;
+	if (*&enemy == old)				enemy = replacement, changed++;
+	if (*&missile == old)			missile = replacement, changed++;
+	if (*&mate == old)				mate = replacement, changed++;
+	if (*&last_mate == old)			last_mate = replacement, changed++;
+	if (ReadyWeapon == old)			ReadyWeapon = static_cast<AWeapon *>(rep), changed++;
+	if (PendingWeapon == old)		PendingWeapon = static_cast<AWeapon *>(rep), changed++;
+	if (*&PremorphWeapon == old)	PremorphWeapon = static_cast<AWeapon *>(rep), changed++;
+	if (*&ConversationNPC == old)	ConversationNPC = replacement, changed++;
+	if (*&ConversationPC == old)	ConversationPC = replacement, changed++;
 	return changed;
 }
 

src/thingdef/thingdef_codeptr.cpp

@@ -2253,7 +2253,20 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckSight)
 
 	for (int i = 0; i < MAXPLAYERS; i++) 
 	{
-		if (playeringame[i] && P_CheckSight(players[i].camera, self, SF_IGNOREVISIBILITY)) return;
+		if (playeringame[i])
+		{
+			// Always check sight from each player.
+			if (P_CheckSight(players[i].mo, self, SF_IGNOREVISIBILITY))
+			{
+				return;
+			}
+			// If a player is viewing from a non-player, then check that too.
+			if (players[i].camera != NULL && players[i].camera->player == NULL &&
+				P_CheckSight(players[i].camera, self, SF_IGNOREVISIBILITY))
+			{
+				return;
+			}
+		}
 	}
 
 	ACTION_JUMP(jump);
@@ -2266,6 +2279,42 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckSight)
 // Useful for maps with many multi-actor special effects.
 //
 //===========================================================================
+static bool DoCheckSightOrRange(AActor *self, AActor *camera, double range)
+{
+	if (camera == NULL)
+	{
+		return false;
+	}
+	// Check distance first, since it's cheaper than checking sight.
+	double dx = self->x - camera->x;
+	double dy = self->y - camera->y;
+	double dz;
+	fixed_t eyez = (camera->z + camera->height - (camera->height>>2));	// same eye height as P_CheckSight
+	if (eyez > self->z + self->height)
+	{
+		dz = self->z + self->height - eyez;
+	}
+	else if (eyez < self->z)
+	{
+		dz = self->z - eyez;
+	}
+	else
+	{
+		dz = 0;
+	}
+	if ((dx*dx) + (dy*dy) + (dz*dz) <= range)
+	{ // Within range
+		return true;
+	}
+
+	// Now check LOS.
+	if (P_CheckSight(camera, self, SF_IGNOREVISIBILITY))
+	{ // Visible
+		return true;
+	}
+	return false;
+}
+
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckSightOrRange)
 {
 	ACTION_PARAM_START(2);
@@ -2279,33 +2328,15 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckSightOrRange)
 	{
 		if (playeringame[i])
 		{
-			AActor *camera = players[i].camera;
-
-			// Check distance first, since it's cheaper than checking sight.
-			double dx = self->x - camera->x;
-			double dy = self->y - camera->y;
-			double dz;
-			fixed_t eyez = (camera->z + camera->height - (camera->height>>2));	// same eye height as P_CheckSight
-			if (eyez > self->z + self->height)
+			// Always check from each player.
+			if (DoCheckSightOrRange(self, players[i].mo, range))
 			{
-				dz = self->z + self->height - eyez;
-			}
-			else if (eyez < self->z)
-			{
-				dz = self->z - eyez;
-			}
-			else
-			{
-				dz = 0;
-			}
-			if ((dx*dx) + (dy*dy) + (dz*dz) <= range)
-			{ // Within range
 				return;
 			}
-
-			// Now check LOS.
-			if (P_CheckSight(camera, self, SF_IGNOREVISIBILITY))
-			{ // Visible
+			// If a player is viewing from a non-player, check that too.
+			if (players[i].camera != NULL && players[i].camera->player == NULL &&
+				DoCheckSightOrRange(self, players[i].camera, range))
+			{
 				return;
 			}
 		}

src/version.h

@@ -54,7 +54,7 @@
 // Version identifier for network games.
 // Bump it every time you do a release unless you're certain you
 // didn't change anything that will affect sync.
-#define NETGAMEVERSION 226
+#define NETGAMEVERSION 227
 
 // Version stored in the ini's [LastRun] section.
 // Bump it if you made some configuration change that you want to
@@ -64,7 +64,7 @@
 // Protocol version used in demos.
 // Bump it if you change existing DEM_ commands or add new ones.
 // Otherwise, it should be safe to leave it alone.
-#define DEMOGAMEVERSION 0x217
+#define DEMOGAMEVERSION 0x218
 
 // Minimum demo version we can play.
 // Bump it whenever you change or remove existing DEM_ commands.