- New: On Windows, the game now checks the registry to see if you have Steam

installed. If so, it checks your SteamApps directory for any IWADs you may
  have purchased through Steam and adds any it finds to the list of available
  IWADs you can play. This means that if you bought your id games through
  Steam, you can just extract ZDoom anywhere you like and run it without doing
  any additional setup.


SVN r581 (trunk)

src/d_main.cpp

@@ -1629,6 +1629,26 @@ static EIWADType IdentifyVersion (const char *zdoom_wad)
 				}
 			}
 		}
+#ifdef _WIN32
+		FString steam_path = I_GetSteamPath();
+		if (steam_path.IsNotEmpty())
+		{
+			static const char *const steam_dirs[] =
+			{
+				"doom 2/base",
+				"final doom/base",
+				"heretic shadow of the serpent riders/base",
+				"hexen/base",
+				"hexen deathkings of the dark citadel/base",
+				"ultimate doom/base"
+			};
+			steam_path += "/SteamApps/common/";
+			for (i = 0; i < countof(steam_dirs); ++i)
+			{
+				CheckIWAD (steam_path + steam_dirs[i], wads);
+			}
+		}
+#endif
 	}
 
 	if (iwadparm != NULL && !wads[0].Path.IsEmpty())
@@ -1636,7 +1656,7 @@ static EIWADType IdentifyVersion (const char *zdoom_wad)
 		iwadparmfound = true;
 	}
 
-	for (i = numwads = 0; i < sizeof(IWADNames)/sizeof(char *); i++)
+	for (i = numwads = 0; i < countof(IWADNames); i++)
 	{
 		if (!wads[i].Path.IsEmpty())
 		{