Implemented proper functionality of SE_Screech

If you have a buff with SE_Screech with value of 1
it will block any other buff with SE_Screen that has
a value of -1, giving you an immunity message.
Example: 1383 Screech and 2785 Screech Immunity

common/spdat.h

@@ -270,7 +270,7 @@ typedef enum {
 #define SE_HealRate						120	// implemented - reduces healing by a %
 #define SE_ReverseDS					121 // implemented
 //#define SE_ReduceSkill				122	// not used
-#define SE_Screech						123	// implemented? Spell Blocker(can only have one buff with this effect at one time)
+#define SE_Screech						123	// implemented Spell Blocker(If have buff with value +1 will block any effect with -1)
 #define SE_ImprovedDamage				124 // implemented
 #define SE_ImprovedHeal					125 // implemented
 #define SE_SpellResistReduction			126 // implemented

zone/StringIDs.h

@@ -334,6 +334,7 @@
 #define ALREADY_CASTING				12442	//You are already casting a spell!
 #define SENSE_CORPSE_NOT_NAME		12446	//You don't sense any corpses of that name.
 #define SENSE_CORPSE_NONE			12447	//You don't sense any corpses.
+#define SCREECH_BUFF_BLOCK			12448	//Your immunity buff protected you from the spell %1!
 #define NOT_HOLDING_ITEM			12452	//You are not holding an item!
 #define SENSE_UNDEAD				12471	//You sense undead in this direction.
 #define SENSE_ANIMAL				12472	//You sense an animal in this direction.

zone/bonuses.cpp

@@ -2588,6 +2588,12 @@ void Mob::ApplySpellsBonuses(uint16 spell_id, uint8 casterlevel, StatBonuses* ne
 
 			case SE_NegateIfCombat:
 				newbon->NegateIfCombat = true;
+				break;
+
+			case SE_Screech: 
+				newbon->Screech = effect_value;
+				break;
+			
 		}
 	}
 }

zone/common.h

@@ -346,6 +346,7 @@ struct StatBonuses {
 	uint16	AbsorbMagicAtt[2];					// 0 = magic rune value 1 = buff slot
 	uint16	MeleeRune[2];						// 0 = rune value 1 = buff slot
 	bool	NegateIfCombat;						// Bool Drop buff if cast or melee
+	int8	Screech;							// -1 = Will be blocked if another Screech is +(1)
 
 	// AAs
 	int8	Packrat;							//weight reduction for items, 1 point = 10%

zone/spells.cpp

@@ -2613,6 +2613,14 @@ int Mob::CheckStackConflict(uint16 spellid1, int caster_level1, uint16 spellid2,
 		{
 			effect1 = sp1.effectid[i];
 			effect2 = sp2.effectid[i];
+
+			if (spellbonuses.Screech == 1) {
+				if (effect2 == SE_Screech && sp2.base[i] == -1) {
+					Message_StringID(MT_SpellFailure, SCREECH_BUFF_BLOCK, sp2.name);
+					return -1;
+				}
+			}
+
 			if(effect2 == SE_StackingCommand_Overwrite)
 			{
 				overwrite_effect = sp2.base[i];
@@ -2657,7 +2665,7 @@ int Mob::CheckStackConflict(uint16 spellid1, int caster_level1, uint16 spellid2,
 					mlog(SPELLS__STACKING, "%s (%d) blocks effect %d on slot %d below %d, but we do not have that effect on that slot. Ignored.",
 						sp1.name, spellid1, blocked_effect, blocked_slot, blocked_below_value);
 				}
-			}
+			} 
 		}
 	} else {
 		mlog(SPELLS__STACKING, "%s (%d) and %s (%d) appear to be in the same line, skipping Stacking Overwrite/Blocking checks",