New effect: Merge weapons ammo

src/gtasa/effects/custom/player/MergeWeaponsAmmoEffect.cpp

@@ -0,0 +1,193 @@
+#include "util/EffectBase.h"
+#include "util/hooks/HookMacros.h"
+
+#include <cstdio>
+namespace
+{
+enum eWeaponSlot
+{
+    UNARMED,
+    MELEE,
+    HANDGUN,
+    SHOTGUN,
+    SMG,
+    RIFLE,
+    SNIPER,
+    HEAVY,
+    THROWN,
+    SPECIAL,
+    GIFT,
+    PARACHUTE,
+    DETONATOR,
+};
+} // namespace
+
+using namespace plugin;
+
+class MergeWeaponsAmmoEffect : public EffectBase
+{
+    static inline bool *infiniteAmmoCheat = nullptr;
+    static inline int   totalAmmo         = 0;
+    static inline bool  isValidWeapon     = false;
+
+public:
+    void
+    OnStart (EffectInstance *inst) override
+    {
+        infiniteAmmoCheat = reinterpret_cast<bool *> (0x969178);
+        HOOK_METHOD_ARGS (inst, Hooked_Weapon_Fire,
+                          bool (CWeapon *, CPed *, CVector *, CVector *,
+                                CEntity *, CVector *, CVector *),
+                          0x742300);
+        HOOK_METHOD_ARGS (inst, Hooked_Weapon_FireFromCar,
+                          bool (CWeapon *, CVehicle *, bool, bool), 0x73FA20);
+
+        patch::RedirectCall (0x589498, Redirect_AsciiToGxtChar);
+    }
+
+    void
+    OnEnd (EffectInstance *inst)
+    {
+        patch::RedirectCall (0x589498, AsciiToGxtChar);
+    }
+
+    void
+    OnTick (EffectInstance *inst) override
+    {
+        auto *player = FindPlayerPed ();
+        if (!player) return;
+
+        totalAmmo = 0;
+        for (int i = HANDGUN; i < SPECIAL; i++)
+        {
+            if (!player->m_aWeapons[i].m_eWeaponType)
+            {
+                continue;
+            }
+            totalAmmo += player->m_aWeapons[i].m_nTotalAmmo;
+        }
+        isValidWeapon         = false;
+        auto activeWeaponSlot = player->m_nActiveWeaponSlot;
+        if (activeWeaponSlot >= HANDGUN && activeWeaponSlot < SPECIAL)
+        {
+            isValidWeapon = true;
+        }
+    }
+
+    static void
+    Redirect_AsciiToGxtChar (const char *src, char *dst)
+    {
+        std::array<char, 32> buff;
+        buff.fill (0);
+        std::sprintf (buff.data (), "%d", totalAmmo);
+
+        const char *p = isValidWeapon ? buff.data () : src;
+
+        AsciiToGxtChar (p, dst);
+    }
+
+    static bool
+    Hooked_Weapon_Fire (auto &&cb, CWeapon *thisWeapon, CPed *owner,
+                        CVector *vecOrigin, CVector *_vecEffectPosn,
+                        CEntity *targetEntity, CVector *vecTarget,
+                        CVector *arg_14)
+    {
+        auto *player = FindPlayerPed ();
+        if (owner != player || !player)
+        {
+            return cb ();
+        }
+
+        if (*infiniteAmmoCheat) // already active, skip the next logic
+        {
+            return cb ();
+        }
+
+        if (isValidWeapon)
+        {
+            int activeSlot     = player->m_nActiveWeaponSlot;
+            *infiniteAmmoCheat = true; // hack to decrease ammo manually
+            auto hasFire       = cb ();
+            *infiniteAmmoCheat = false;
+
+            if (hasFire)
+            {
+                DecreaseAmmo (activeSlot);
+            }
+
+            return hasFire;
+        }
+
+        return cb ();
+    }
+
+    static bool
+    Hooked_Weapon_FireFromCar (auto &&cb, CWeapon *thisWeapon,
+                               CVehicle *vehicle, bool leftSide, bool rightSide)
+    {
+        auto *player = FindPlayerPed ();
+        if (vehicle->m_pDriver != player || !player)
+        {
+            return cb ();
+        }
+
+        if (*infiniteAmmoCheat) // already active, skip the next logic
+        {
+            return cb ();
+        }
+
+        if (isValidWeapon)
+        {
+            int activeSlot     = player->m_nActiveWeaponSlot;
+            *infiniteAmmoCheat = true; // hack to decrease ammo manually
+            auto hasFire       = cb ();
+            *infiniteAmmoCheat = false;
+
+            if (hasFire)
+            {
+                DecreaseAmmo (activeSlot);
+            }
+
+            return hasFire;
+        }
+
+        return cb ();
+    }
+
+    static void
+    DecreaseAmmo (int slot)
+    {
+        auto *player = FindPlayerPed ();
+        auto &weapon = player->m_aWeapons[slot];
+
+        if (weapon.m_nTotalAmmo > 2)
+        {
+            weapon.m_nTotalAmmo--;
+        }
+        else
+        {
+            bool forceDecreaseAmmo = true;
+            for (int i = HANDGUN; i < SPECIAL; i++)
+            {
+                if (!player->m_aWeapons[i].m_eWeaponType || i == slot)
+                {
+                    continue;
+                }
+                if (player->m_aWeapons[i].m_nTotalAmmo > 0)
+                {
+                    player->m_aWeapons[i].m_nTotalAmmo--;
+                    forceDecreaseAmmo = false;
+                    break;
+                }
+            }
+
+            if (forceDecreaseAmmo)
+            {
+                weapon.m_nTotalAmmo--;
+            }
+        }
+    }
+};
+
+DEFINE_EFFECT (MergeWeaponsAmmoEffect, "effect_merge_weapons_ammo",
+               GROUP_WEAPONS);