Hexen: Add optional fix for vanilla bug with Heresiarch zero cast time

Bug:
When Heresiarch loses his target, he switches to Spawn state and
spawns another set of his cubes. Each additional cube reduces cast time
until it becomes instant. This leads to permanent invulnerability spell.

Fix:
When Heresiarch loses his target, switch to the third frame of Spawn state, skipping spawn of cubes.

Switch available in config as `heresiarch_zero_cast_time_fix` parameter. 1 - fix enabled, 0 - fix disabled.
Enabled by default in Recommended settings and disabled in Vanilla settings.

src/hexen/h2_main.c

@@ -243,6 +243,9 @@ int breathing = 0;
 int skip_unused_artifact = 0;
 int pistol_start = 0;
 
+// [Dasperal] Vanila bugs fixes
+int heresiarch_zero_cast_time_fix = 1;
+
 int selective_class = 0;
 int selective_skill = 2;
 int selective_episode = 1;
@@ -409,6 +412,9 @@ void D_BindVariables(void)
     M_BindIntVariable("skip_unused_artifact",   &skip_unused_artifact);
     M_BindIntVariable("pistol_start",   &pistol_start);
 
+    // [Dasperal] Vanila bugs fixes
+    M_BindIntVariable("heresiarch_zero_cast_time_fix", &heresiarch_zero_cast_time_fix);
+
     // Gameplay: Crosshair
     M_BindIntVariable("crosshair_draw",         &crosshair_draw);
     M_BindIntVariable("crosshair_shape",        &crosshair_shape);

src/hexen/h2def.h

@@ -731,6 +731,9 @@ extern boolean skippsprinterp;
 
 extern int artiskip;            // whether shift-enter skips an artifact
 
+// [Dasperal] Vanila bugs fixes
+extern int heresiarch_zero_cast_time_fix;
+
 /*
 ===============================================================================
 

src/hexen/mn_menu.c

@@ -5919,6 +5919,7 @@ void M_RD_BackToDefaults_Recommended (void)
     weapon_widget        = 0;
     skip_unused_artifact = 0;
     pistol_start = 0;
+    heresiarch_zero_cast_time_fix = 1;
     // Gameplay (4)
     crosshair_draw       = 0;
     crosshair_shape      = 0;
@@ -6038,6 +6039,7 @@ static void M_RD_BackToDefaults_Original(void)
     weapon_widget        = 0;
     skip_unused_artifact = 1;
     pistol_start = 0;
+    heresiarch_zero_cast_time_fix = 0;
     // Gameplay (4)
     crosshair_draw       = 0;
     crosshair_shape      = 0;

src/hexen/p_enemy.c

@@ -718,13 +718,29 @@ void A_Chase(mobj_t *actor, player_t *player, pspdef_t *psp)
         }
     }
 
-    if (!actor->target || !(actor->target->flags & MF_SHOOTABLE))
-    {                           // look for a new target
-        if (P_LookForPlayers(actor, true))
-        {                       // got a new target
+    if(!actor->target || !(actor->target->flags & MF_SHOOTABLE))
+    {
+        // look for a new target
+        if(P_LookForPlayers(actor, true))
+        {
+            // got a new target
             return;
         }
-        P_SetMobjState(actor, actor->info->spawnstate);
+
+        if(heresiarch_zero_cast_time_fix && actor->type == MT_SORCBOSS)
+        {
+            // Bug:
+            // When Heresiarch loses his target, he switches to Spawn state and
+            // spawns another set of his cubes. Each additional cube reduces cast time
+            // until it becomes instant. This leads to permanent invulnerability spell.
+            // Fix:
+            // When Heresiarch looses his target, switch to the third frame of Spawn state, skipping spawn of cubes.
+            P_SetMobjState(actor, S_SORC_LOOK1);
+        }
+        else
+        {
+            P_SetMobjState(actor, actor->info->spawnstate);
+        }
         return;
     }
 

src/m_config.c

@@ -678,6 +678,9 @@ static default_t defaults_list[] =
     CONFIG_VARIABLE_INT(fast_quickload),
     CONFIG_VARIABLE_INT(skip_unused_artifact),
 
+    // [Dasperal] Vanila bugs fixes
+    CONFIG_VARIABLE_INT(heresiarch_zero_cast_time_fix),
+
     // Gameplay: Demos
     CONFIG_VARIABLE_INT(demotimer),
     CONFIG_VARIABLE_INT(demotimerdir),