From d114dffcb499a79755be5d4f5927cb2adfb3339d Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Tue, 13 Aug 2024 17:21:40 +0300
Subject: [PATCH] filesystem: add new gameinfo.txt key: demomap

---
 Documentation/gameinfo.md |  1 +
 filesystem/filesystem.c   | 15 +++++++++++++++
 filesystem/filesystem.h   |  1 +
 3 files changed, 17 insertions(+)

diff --git a/Documentation/gameinfo.md b/Documentation/gameinfo.md
index af9109ec..868a10c9 100644
--- a/Documentation/gameinfo.md
+++ b/Documentation/gameinfo.md
@@ -78,6 +78,7 @@ These strings are specific to Xash3D FWGS.
 | `internal_vgui_support` | boolean    | 0                        | Only for programmers! Required to be set as 1 for PrimeXT!<br>When set to 1, the engine will not load vgui_support DLL, as VGUI support is done (or intentionally ignored) on the game side. |
 | `render_picbutton_text` | boolean    | 0                        | When set to 1, the UI will not use prerendered `btns_main.bmp` and dynamically render them instead |
 | `quicksave_aged_count`  | integer    | 2                        | Quick saves limit used in saves rotation |
+| `demomap`               | string     | Empty string             | The name of the demo chapter map (Half-Life Uplink) |
 
 ## Note on GoldSrc liblist.gam support
 
diff --git a/filesystem/filesystem.c b/filesystem/filesystem.c
index 53bf6d20..60695f16 100644
--- a/filesystem/filesystem.c
+++ b/filesystem/filesystem.c
@@ -619,6 +619,9 @@ static void FS_WriteGameInfo( const char *filepath, gameinfo_t *GameInfo )
 	FS_Printf( f, "internal_vgui_support\t\t%s\n", GameInfo->internal_vgui_support ? "1" : "0" );
 	FS_Printf( f, "render_picbutton_text\t\t%s\n", GameInfo->render_picbutton_text ? "1" : "0" );
 
+	if( COM_CheckStringEmpty( GameInfo->demomap ))
+		FS_Printf( f, "demomap\t\t\"%s\"\n", GameInfo->demomap );
+
 	FS_Close( f );	// all done
 }
 
@@ -879,9 +882,21 @@ static void FS_ParseGenericGameInfo( gameinfo_t *GameInfo, const char *buf, cons
 				pfile = COM_ParseFile( pfile, token, sizeof( token ));
 				GameInfo->autosave_aged_count = bound( 2, Q_atoi( token ), 99 );
 			}
+			else if( !Q_stricmp( token, "demomap" ))
+			{
+				pfile = COM_ParseFile( pfile, GameInfo->demomap, sizeof( GameInfo->demomap ));
+			}
 		}
 	}
 
+	// demomap only valid for gameinfo.txt but HL1 after 25th anniversary update
+	// comes with demo chapter. Set the demomap here.
+	if( !COM_CheckStringEmpty( GameInfo->demomap ))
+	{
+		if( !Q_stricmp( GameInfo->title, "Half-Life" )) // original check from GameUI
+			Q_strncpy( GameInfo->demomap, "hldemo1", sizeof( GameInfo->demomap ));
+	}
+
 	if( !found_linux || !found_osx )
 	{
 		// just replace extension from dll to so/dylib
diff --git a/filesystem/filesystem.h b/filesystem/filesystem.h
index 0cb6b2aa..74bdda57 100644
--- a/filesystem/filesystem.h
+++ b/filesystem/filesystem.h
@@ -118,6 +118,7 @@ typedef struct gameinfo_s
 	// HL25 compatibility keys
 	qboolean hd_background;
 	qboolean animated_title;
+	char demomap[MAX_QPATH];
 } gameinfo_t;
 
 typedef enum