Exit with error on startup if using the wrong IWAD.

Having multiple binaries can cause some confusion - some users try to
run chocolate-doom with hexen.wad, thinking it is supported. Add a
startup check that makes sure the user is not trying to start the game
using the wrong IWAD file for the binary being run.

This fixes #382.

1 files changed, 43 insertions, 0 deletions

diff --git a/src/w_wad.c b/src/w_wad.c
index 4f944fee..1bb01774 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -34,6 +34,8 @@
 
 #include "doomtype.h"
 
+#include "config.h"
+#include "d_iwad.h"
 #include "i_swap.h"
 #include "i_system.h"
 #include "i_video.h"
@@ -537,3 +539,44 @@ void W_GenerateHashTable(void)
     // All done!
 }
 
+// Lump names that are unique to particular game types. This lets us check
+// the user is not trying to play with the wrong executable, eg.
+// chocolate-doom -iwad hexen.wad.
+static const struct
+{
+    GameMission_t mission;
+    char *lumpname;
+} unique_lumps[] = {
+    { doom,    "POSSA1" },
+    { heretic, "IMPXA1" },
+    { hexen,   "ETTNA1" },
+    { strife,  "AGRDA1" },
+};
+
+void W_CheckCorrectIWAD(GameMission_t mission)
+{
+    int i;
+    int lumpnum;
+
+    for (i = 0; i < arrlen(unique_lumps); ++i)
+    {
+        if (mission != unique_lumps[i].mission)
+        {
+            lumpnum = W_CheckNumForName(unique_lumps[i].lumpname);
+
+            if (lumpnum >= 0)
+            {
+                I_Error("\nYou are trying to use a %s IWAD file with "
+                        "the %s%s binary.\nThis isn't going to work.\n"
+                        "You probably want to use the %s%s binary.",
+                        D_SuggestGameName(unique_lumps[i].mission,
+                                          indetermined),
+                        PROGRAM_PREFIX,
+                        D_GameMissionString(mission),
+                        PROGRAM_PREFIX,
+                        D_GameMissionString(unique_lumps[i].mission));
+            }
+        }
+    }
+}
+