Put the client into pause mode when loading save games.

This prevenits the worlds from advancing during client connect. The
player won't get attacked by monsters or hurt by the environment. Note
that in baseq2 there're still 4 world frames processed by the game and
100 world frames if the player enters a level that he or she already
visited. Both aren't a big problem, 4 world frames are hardly enough
for monsters starting to attack and in most levels the starting area
can't be reached by monsters and is free from environmental effects.

Pause mode is only entered for local servers and only in single player
mode. This should prevent problems with coop and deathmatch games.

The behaviour can be controlled by `cl_loadpaused`:
* `0`: Do not enter pause mode, Vanilla Quake I behaviour.
* `1`: Enter pause mode at load and leave it at first regular server
       frame.
* `2`: Enter pause mode at load, never leave it. The player must leave
       it by hand.

This was requested in issue #417.

doc/04_cvarlist.md

@@ -63,6 +63,13 @@ it's `+set busywait 0` (setting the `busywait` cvar) and `-portable`
   If *cl_async* is set to `0` *vid_maxfps* is the same as *cl_maxfps*,
   use *cl_maxfps* to set the framerate.
 
+* **cl_loadpaused**: If set to `1` (the default) the client is put into
+  pause mode during single player savegame load. This prevents monsters
+  and the environment from hurting the player while the client is still
+  connecting. If set to `2` the client stays in pause mode after
+  loading. If set to `0` pause mode is never entered, this is the
+  Vanilla Quake II behaviour.
+
 * **cl_showfps**: Shows the framecounter. Set to `2` for more and to
   `3` for even more informations.
 

src/client/cl_main.c

@@ -56,6 +56,7 @@ cvar_t *cl_showmiss;
 cvar_t *cl_showclamp;
 
 cvar_t *cl_paused;
+cvar_t *cl_loadpaused;
 
 cvar_t *lookstrafe;
 cvar_t *sensitivity;
@@ -97,6 +98,11 @@ entity_state_t cl_parse_entities[MAX_PARSE_ENTITIES];
   fires his shotgun onto a Brain. */
 int num_power_sounds;
 
+/* Used to communicate if we entered paused mode
+   during server connect or if we were already in
+   it. */
+qboolean paused_at_load;
+
 extern cvar_t *allow_download;
 extern cvar_t *allow_download_players;
 extern cvar_t *allow_download_models;
@@ -524,6 +530,7 @@ CL_InitLocal(void)
 	cl_showclamp = Cvar_Get("showclamp", "0", 0);
 	cl_timeout = Cvar_Get("cl_timeout", "120", 0);
 	cl_paused = Cvar_Get("paused", "0", 0);
+	cl_loadpaused = Cvar_Get("cl_loadpaused", "1", CVAR_ARCHIVE);
 
 	gl1_stereo = Cvar_Get( "gl1_stereo", "0", CVAR_ARCHIVE );
 	gl1_stereo_separation = Cvar_Get( "gl1_stereo_separation", "1", CVAR_ARCHIVE );

src/client/cl_network.c

@@ -617,6 +617,40 @@ CL_ConnectionlessPacket(void)
 			}
 		}
 
+		/* Put client into pause mode when connecting to a local server.
+		   This prevents the world from being forwarded while the client
+		   is connecting, loading assets, etc. It's not 100%, there're
+		   still 4 world frames (for baseq2) processed in the game and
+		   100 frames by the server if the player enters a level that he
+		   or she already visited. In practise both shouldn't be a big
+		   problem. 4 frames are hardly enough for monsters staring to
+		   attack and in most levels the starting area in unreachable by
+		   monsters and free from environmental effects.
+
+		   Com_Serverstate() returns > 1 if the server is local, otherwise
+		   0. If it's a local server, maxclients aus either 0 (for single
+		   player), or 2 to 8 (coop and deathmatch) if we're reaching this
+		   code. For remote servers it's always 1. So this should trigger
+		   only if it's a local single player server.
+
+		   Since the player can load savegames from a paused state (e.g.
+		   through the console) we'll need to communicate if we entered
+		   paused mode (and it should left as soon as the player joined
+		   the server) or if it was already there.
+
+		   Last but not least this can be disabled by cl_loadpaused 0. */
+		if (Com_ServerState() || (Cvar_VariableValue("maxclients") <= 1))
+		{
+			if (cl_loadpaused->value)
+			{
+				if (!cl_paused->value)
+				{
+					paused_at_load = true;
+					Cvar_Set("paused", "1");
+				}
+			}
+		}
+
 		MSG_WriteChar(&cls.netchan.message, clc_stringcmd);
 		MSG_WriteString(&cls.netchan.message, "new");
 		cls.state = ca_connected;

src/client/cl_parse.c

@@ -798,6 +798,14 @@ CL_ParseFrame(void)
 			}
 
 			cl.sound_prepped = true;
+
+			if (paused_at_load)
+			{
+				if (cl_loadpaused->value == 1)
+				{
+					Cvar_Set("paused", "0");
+				}
+			}
 		}
 
 		/* fire entity events */

src/client/header/client.h

@@ -297,6 +297,7 @@ extern	cvar_t	*m_side;
 extern	cvar_t	*freelook;
 extern	cvar_t	*cl_lightlevel;
 extern	cvar_t	*cl_paused;
+extern	cvar_t	*cl_loadpaused;
 extern	cvar_t	*cl_timedemo;
 extern	cvar_t	*cl_vwep;
 extern	cvar_t  *horplus;
@@ -321,6 +322,8 @@ extern	entity_state_t	cl_parse_entities[MAX_PARSE_ENTITIES];
 extern	netadr_t	net_from;
 extern	sizebuf_t	net_message;
 
+extern qboolean paused_at_load;
+
 void DrawString (int x, int y, char *s);
 void DrawStringScaled(int x, int y, char *s, float factor);
 void DrawAltString (int x, int y, char *s);	/* toggle high bit */