From 1c4d48f5f2183317ed89e14c928c2b0f0f809e99 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 17 Apr 2022 08:53:52 +0200
Subject: [PATCH] - added some fudging so that the Dehacked parser can properly
 deal with ConsumeAmmo.

This is a parameterized code pointer, so checking state functions for names won't work. Additionally, the handling was not correct for weapons with an ammo use other than 1.
---
 src/gamedata/d_dehacked.cpp | 22 +++++++++++++++++++---
 src/gamedata/info.h         |  1 +
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/gamedata/d_dehacked.cpp b/src/gamedata/d_dehacked.cpp
index 232dec896..99cba80b4 100644
--- a/src/gamedata/d_dehacked.cpp
+++ b/src/gamedata/d_dehacked.cpp
@@ -237,7 +237,6 @@ static AmmoPerAttack AmmoPerAttacks[] = {
 	{ NAME_A_FireBFG, -1},	// uses deh.BFGCells
 	{ NAME_A_FireOldBFG, 1},
 	{ NAME_A_FireRailgun, 1},
-	{ NAME_MBF21_ConsumeAmmo, 1}, // MBF21
 	{ NAME_None, 0}
 };
 
@@ -2588,12 +2587,16 @@ static int PatchCodePtrs (int dummy)
 			{
 				FString symname;
 
-
 				if ((Line2[0] == 'A' || Line2[0] == 'a') && Line2[1] == '_')
 					symname = Line2;
 				else
 					symname.Format("A_%s", Line2);
 
+				// Hack alert: If A_ConsumeAmmo is used we need to handle the ammo use differently.
+				// Since this is a parameterized code pointer the AmmoPerAttack check cannot find it easily without some help.
+				if (symname.CompareNoCase("A_ConsumeAmmo") == 0)
+					state->StateFlags |= STF_CONSUMEAMMO;
+
 				// Let's consider as aliases some redundant MBF pointer
 				bool ismbfcp = false;
 				for (unsigned int i = 0; i < MBFCodePointers.Size(); i++)
@@ -3571,8 +3574,8 @@ void FinishDehPatch ()
 		}
 		else
 		{
+			bool handled = false;
 			weap->BoolVar(NAME_bDehAmmo) = true;
-			weap->IntVar(NAME_AmmoUse1) = 0;
 			// to allow proper checks in CheckAmmo we have to find the first attack pointer in the Fire sequence
 			// and set its default ammo use as the weapon's AmmoUse1.
 
@@ -3587,6 +3590,13 @@ void FinishDehPatch ()
 					break;	// State has already been checked so we reached a loop
 				}
 				StateVisited[state] = true;
+				if (state->StateFlags & STF_CONSUMEAMMO)
+				{
+					// If A_ConsumeAmmo is being used we have to rely on the existing AmmoUse1 value.
+					handled = true;
+					state->StateFlags &= ~STF_CONSUMEAMMO;
+					break;
+				}
 				for(unsigned j = 0; AmmoPerAttacks[j].func != NAME_None; j++)
 				{
 					if (AmmoPerAttacks[j].ptr == nullptr)
@@ -3601,12 +3611,18 @@ void FinishDehPatch ()
 						int use = AmmoPerAttacks[j].ammocount;
 						if (use < 0) use = deh.BFGCells;
 						weap->IntVar(NAME_AmmoUse1) = use;
+						handled = true;
 						break;
 					}
 				}
 				if (found) break;
 				state = state->GetNextState();
 			}
+			if (!handled)
+			{
+				weap->IntVar(NAME_AmmoUse1) = 0;
+
+			}
 		}
 	}
 	WeaponNames.Clear();
diff --git a/src/gamedata/info.h b/src/gamedata/info.h
index 0d2eadac4..d9e89037b 100644
--- a/src/gamedata/info.h
+++ b/src/gamedata/info.h
@@ -72,6 +72,7 @@ enum EStateFlags
 	STF_SAMEFRAME = 16,	// Ignore Frame (except when spawning actor)
 	STF_CANRAISE = 32,	// Allows a monster to be resurrected without waiting for an infinate frame
 	STF_DEHACKED = 64,	// Modified by Dehacked
+	STF_CONSUMEAMMO = 128,	// Needed by the Dehacked parser.
 };
 
 enum EStateType : int // this must ensure proper alignment.