Add "TITLEPIC/CREDIT cycle" for WADs with blank internal demos

prboom2/src/d_main.c

@@ -654,6 +654,18 @@ void D_PageTicker(void)
     D_AdvanceDemo();
 }
 
+// Check whether to skip IWAD Demos
+static int dsda_SkipIwadDemos(void)
+{
+  int pwaddemo = W_PWADLumpNameExists("DEMO1");
+  int pwadmaps = W_PWADLumpNameExists("THINGS");
+
+  if ((pwadmaps && !pwaddemo) || lumpinfo[W_CheckNumForName("DEMO1")].size == 0)
+    return true;
+
+  return false;
+}
+
 //
 // D_PageDrawer
 //
@@ -682,8 +694,10 @@ static void D_PageDrawer(void)
     V_ClearBorder();
     V_DrawNamePatchFS(0, 0, 0, pagename, CR_DEFAULT, VPT_STRETCH);
   }
-  else
+  else if (dsda_SkipIwadDemos() && W_PWADLumpNameExists("CREDIT"))
     M_DrawCredits();
+  else
+    M_DrawCreditsDynamic();
 }
 
 //
@@ -826,6 +840,17 @@ void D_DoAdvanceDemo(void)
   if (demosequence == 6 && gamemode == commercial && !W_LumpNameExists("demo4"))
     demosequence = 0;
 
+  if (dsda_SkipIwadDemos())
+  {
+    // Skip blank / IWAD demos in PWADs
+    if (demostates[demosequence][gamemode].func == G_DeferedPlayDemo)
+      demosequence++;
+
+    // Limit to just TITLEPIC / CREDIT
+    if (demosequence > (raven ? 3 : 2))
+      demosequence = 0;
+  }
+
   demostates[demosequence][gamemode].func(demostates[demosequence][gamemode].name);
 }
 

prboom2/src/m_menu.c

@@ -604,8 +604,17 @@ static void M_DrawReadThis1(void)
 
 static void M_DrawReadThis2(void)
 {
+  const char* helplump = (gamemode == commercial) ? "HELP" : "HELP1";
+  int pwadmaps = W_PWADLumpNameExists("THINGS"); // show help screen for IWAD
+
   inhelpscreens = true;
-  M_DrawHelp();
+
+  if (W_PWADLumpNameExists(helplump) || !pwadmaps)
+    M_DrawHelp();
+  else if (W_PWADLumpNameExists("CREDIT"))
+    M_DrawCredits();
+  else
+    M_DrawCreditsDynamic();
 }
 
 /////////////////////////////
@@ -4427,22 +4436,20 @@ setup_menu_t cred_settings[]={
 
 void M_DrawCredits(void)     // killough 10/98: credit screen
 {
-  const char* credit = "CREDIT";
-  const int PWADcredit = W_PWADLumpNameExists(credit);
+  inhelpscreens = true;
+
+  V_ClearBorder();
+  V_DrawNamePatchFS(0, 0, 0, "CREDIT", CR_DEFAULT, VPT_STRETCH);
+}
 
+void M_DrawCreditsDynamic(void)     // Dynamic Credits
+{
   inhelpscreens = true;
-  if (PWADcredit || tc_game)
-  {
-    V_ClearBorder();
-    V_DrawNamePatchFS(0, 0, 0, credit, CR_DEFAULT, VPT_STRETCH);
-  }
-  else
-  {
-    // Use V_DrawBackground here deliberately to force drawing a background
-    V_DrawBackground(gamemode==shareware ? "CEIL5_1" : "MFLR8_4", 0);
-    M_DrawTitle(9, PROJECT_NAME " v" PROJECT_VERSION, cr_title); // PRBOOM
-    M_DrawScreenItems(cred_settings, 32);
-  }
+
+  // Use V_DrawBackground here deliberately to force drawing a background
+  V_DrawBackground(gamemode==shareware ? "CEIL5_1" : "MFLR8_4", 0);
+  M_DrawTitle(9, PROJECT_NAME " v" PROJECT_VERSION, cr_title); // PRBOOM
+  M_DrawScreenItems(cred_settings, 32);
 }
 
 static int M_IndexInChoices(const char *str, const char **choices) {

prboom2/src/m_menu.h

@@ -79,7 +79,8 @@ void M_ForcedLoadGame(const char *msg); // killough 5/15/98: forced loadgames
 
 void M_ResetMenu(void);      // killough 11/98: reset main menu ordering
 
-void M_DrawCredits(void);    // killough 11/98
+void M_DrawCredits(void);
+void M_DrawCreditsDynamic(void);    // killough 11/98
 
 void M_DrawTabs(const char **pages, int m, int y);