Add optional Steam API support for the 2021 rerelease

- achievements
- rich presence
- playtime tracking

Disabled by passing `-nosteamapi` on the command line.

Note: the Steam API library is not distributed with IW and is not required for normal execution, it is only used if it's already present on the player's system.

Quake/cl_parse.c

@@ -25,6 +25,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 #include "quakedef.h"
 #include "bgmusic.h"
+#include "steam.h"
 
 const char *svc_strings[] =
 {
@@ -1373,7 +1374,10 @@ void CL_ParseServerMessage (void)
 		//used by the 2021 rerelease
 		case svc_achievement:
 			str = MSG_ReadString();
-			Con_DPrintf("Ignoring svc_achievement (%s)\n", str);
+			if (cls.demoplayback)
+				Con_DPrintf ("Ignoring svc_achievement (%s)\n", str);
+			else if (!Steam_SetAchievement (str))
+				Con_DPrintf ("Couldn't set achievement \"%s\"\n", str);
 			break;
 		case svc_localsound:
 			CL_ParseLocalSound();

Quake/common.c

@@ -3018,6 +3018,10 @@ static void COM_InitBaseDir (void)
 			else if (!Sys_GetSteamQuakeUserDir (com_nightdivedir, sizeof (com_nightdivedir), steamquake.library))
 				com_nightdivedir[0] = '\0';
 		}
+		else
+		{
+			memset (&steamquake, 0, sizeof (steamquake));
+		}
 		if (steam)
 			goto storesetup;
 	}
@@ -3076,6 +3080,9 @@ static void COM_InitBaseDir (void)
 			flavor = remastered[0] ? QUAKE_FLAVOR_REMASTERED : QUAKE_FLAVOR_ORIGINAL;
 		q_strlcpy (path, flavor == QUAKE_FLAVOR_REMASTERED ? remastered : original, sizeof (path));
 
+		if (steamquake.appid)
+			Steam_Init (&steamquake);
+
 		if (COM_SetBaseDir (path))
 		{
 			if (!Sys_GetAltUserPrefDir (flavor == QUAKE_FLAVOR_REMASTERED, com_userprefdir, sizeof (com_userprefdir)))

Quake/host.c

@@ -24,6 +24,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 #include "quakedef.h"
 #include "bgmusic.h"
+#include "steam.h"
 #include <setjmp.h>
 
 /*
@@ -967,6 +968,8 @@ void Host_ServerFrame (void)
 
 typedef struct summary_s {
 	struct {
+		int		players;
+		int		max_players;
 		int		skill;
 		int		monsters;
 		int		total_monsters;
@@ -976,6 +979,20 @@ typedef struct summary_s {
 	char		map[countof (cl.mapname)];
 } summary_t;
 
+/*
+==================
+CountActiveClients
+==================
+*/
+static int CountActiveClients (void)
+{
+	int i, active;
+	for (i = active = 0; i < cl.maxclients; i++)
+		if (cl.scores[i].name[0])
+			active++;
+	return active;
+}
+
 /*
 ==================
 GetGameSummary
@@ -991,6 +1008,8 @@ static void GetGameSummary (summary_t *s)
 	else
 	{
 		q_strlcpy (s->map, cl.mapname, countof (s->map));
+		s->stats.players        = CountActiveClients ();
+		s->stats.max_players    = cl.maxclients;
 		s->stats.skill          = (int) skill.value;
 		s->stats.monsters       = cl.stats[STAT_MONSTERS];
 		s->stats.total_monsters = cl.stats[STAT_TOTALMONSTERS];
@@ -1007,7 +1026,7 @@ UpdateWindowTitle
 static void UpdateWindowTitle (void)
 {
 	static float timeleft = 0.f;
-	static summary_t last;
+	static summary_t last = {{-1}}; // negative value to force initial update
 	summary_t current;
 
 	timeleft -= host_frametime;
@@ -1039,10 +1058,19 @@ static void UpdateWindowTitle (void)
 			current.stats.secrets, current.stats.total_secrets
 		);
 		VID_SetWindowTitle (title);
+
+		if (current.stats.max_players > 1)
+			Steam_SetStatus_Multiplayer (current.stats.players, current.stats.max_players, utf8name);
+		else
+			Steam_SetStatus_SinglePlayer (utf8name);
 	}
 	else
 	{
 		VID_SetWindowTitle (WINDOW_TITLE_STRING);
+		if (cls.state == ca_connected)
+			Steam_ClearStatus ();
+		else
+			Steam_SetStatus_Menu ();
 	}
 }
 
@@ -1444,6 +1472,8 @@ void Host_Shutdown(void)
 // keep Con_Printf from trying to update the screen
 	scr_disabled_for_loading = true;
 
+	Steam_Shutdown ();
+
 	AsyncQueue_Destroy (&async_queue);
 
 	Host_ShutdownSave ();

Quake/menu.c

@@ -1410,6 +1410,7 @@ void M_SinglePlayer_Key (int key)
 			Cbuf_AddText ("maxplayers 1\n");
 			Cbuf_AddText ("deathmatch 0\n"); //johnfitz
 			Cbuf_AddText ("coop 0\n"); //johnfitz
+			Cbuf_AddText ("campaign 1\n");
 			Cbuf_AddText ("map start\n");
 			break;
 
@@ -2201,6 +2202,7 @@ void M_Skill_Key (int key)
 			Cbuf_AddText ("maxplayers 1\n");
 			Cbuf_AddText ("deathmatch 0\n"); //johnfitz
 			Cbuf_AddText ("coop 0\n"); //johnfitz
+			Cbuf_AddText ("campaign 0\n");
 			Cbuf_AddText (va ("map \"%s\"\n", m_skill_mapname));
 		}
 		break;