Fix coop weapon pickup limits

gamemode/weaponsystem.lua

@@ -15,6 +15,30 @@ local respawnDelay = CreateConVar(
 local trackedItems = {}
 local suppressRespawns = false
 
+-- Sandbox defaults this to 9999, overriding every Source ammo type's intended
+-- carry limit. Coop uses the original per-ammo limits instead.
+local maxAmmoOverride = GetConVar("gmod_maxammo")
+if maxAmmoOverride and maxAmmoOverride:GetInt() > 0 then
+    RunConsoleCommand("gmod_maxammo", "0")
+end
+
+local function ClampPlayerAmmo(ply)
+    for ammoType = 1, 255 do
+        local maximum = game.GetAmmoMax(ammoType)
+        if maximum and maximum >= 0 and ply:GetAmmoCount(ammoType) > maximum then
+            ply:SetAmmo(maximum, ammoType)
+        end
+    end
+end
+
+-- Also repairs reserves accumulated while the sandbox-wide 9999 override was
+-- active. Unknown and explicitly infinite ammo types are left unchanged.
+timer.Simple(0, function()
+    for _, ply in ipairs(player.GetAll()) do
+        if IsValid(ply) then ClampPlayerAmmo(ply) end
+    end
+end)
+
 -- These use the item_ prefix but are map machinery or containers rather than
 -- touch pickups. Ammo crates are already infinite; the others may be removed
 -- deliberately by Hammer I/O and must not be recreated as loose supplies.
@@ -42,16 +66,18 @@ local itemAmmoTypes = {
     item_rpg_round = "RPG_Round"
 }
 
+-- These weapons store their ammunition directly on the player rather than in
+-- a clip, so Clip1() cannot tell us how much a duplicate pickup is worth.
+local cliplessWeaponAmmo = {
+    weapon_frag = 1,
+    weapon_rpg = 1,
+    weapon_slam = 1
+}
+
 local function CanReceiveAmmo(ply, ammoType)
     if ammoType == nil or ammoType < 0 then return false end
 
-    local maximum
-    local maxAmmoOverride = GetConVar("gmod_maxammo")
-    if maxAmmoOverride and maxAmmoOverride:GetInt() > 0 then
-        maximum = maxAmmoOverride:GetInt()
-    else
-        maximum = game.GetAmmoMax(ammoType)
-    end
+    local maximum = game.GetAmmoMax(ammoType)
 
     -- Unknown/custom ammo types are left to their own pickup implementation.
     if maximum == nil or maximum < 0 then return true end
@@ -74,6 +100,8 @@ local function CaptureTemplate(ent)
         bodygroups[bodygroup.id] = ent:GetBodygroup(bodygroup.id)
     end
 
+    local isWeapon = ent:IsWeapon()
+
     return {
         className = ent:GetClass(),
         position = ent:GetPos(),
@@ -85,7 +113,9 @@ local function CaptureTemplate(ent)
         collisionGroup = ent:GetCollisionGroup(),
         name = ent:GetName(),
         keyValues = ent:GetKeyValues(),
-        bodygroups = bodygroups
+        bodygroups = bodygroups,
+        clip1 = isWeapon and ent:Clip1() or nil,
+        clip2 = isWeapon and ent:Clip2() or nil
     }
 end
 
@@ -104,8 +134,11 @@ end
 TrackItem = function(ent, template)
     if not IsValid(ent) or trackedItems[ent] then return end
 
-    template = template or CaptureTemplate(ent)
+    template = template or ent.CustomCoopRespawnTemplate or CaptureTemplate(ent)
     trackedItems[ent] = template
+    -- Lua entity fields survive script auto-refresh. Keeping the template on
+    -- the entity lets a fresh copy of this file recover its original spawn.
+    ent.CustomCoopRespawnTemplate = template
 
     ent:CallOnRemove("CustomCoopRespawnItem", function(removed)
         local savedTemplate = trackedItems[removed]
@@ -147,6 +180,11 @@ RespawnItem = function(template)
         return
     end
 
+    -- Spawn normally fills these from the weapon script. Restore the captured
+    -- values as well so mapper-specified pickup quantities survive recreation.
+    if template.clip1 ~= nil then ent:SetClip1(template.clip1) end
+    if template.clip2 ~= nil then ent:SetClip2(template.clip2) end
+
     ent:SetSkin(template.skin or 0)
     ent:SetMaterial(template.material or "")
     ent:SetColor(template.color or color_white)
@@ -168,6 +206,19 @@ hook.Add("OnEntityCreated", "CustomCoopTrackMapItems", function(ent)
     end)
 end)
 
+local function TrackExistingItems()
+    for _, ent in ipairs(ents.GetAll()) do
+        if IsRespawnable(ent) and (ent:CreatedByMap() or ent.CustomCoopRespawnTemplate) then
+            TrackItem(ent)
+        end
+    end
+end
+
+-- InitPostEntity handles a normal map load; the zero-delay scan handles GMod's
+-- script auto-refresh, where existing entities do not fire OnEntityCreated.
+hook.Add("InitPostEntity", "CustomCoopTrackExistingMapItems", TrackExistingItems)
+timer.Simple(0, TrackExistingItems)
+
 hook.Add("WeaponEquip", "CustomCoopRespawnCollectedWeapon", function(weapon)
     local template = trackedItems[weapon]
     if not template then return end
@@ -179,17 +230,46 @@ hook.Add("WeaponEquip", "CustomCoopRespawnCollectedWeapon", function(weapon)
     ScheduleRespawn(template)
 end)
 
--- A duplicate weapon is removed through WEAPON:EquipAmmo even when the player
--- cannot accept more ammo. Refusing only the useless attempt leaves the pickup
--- available and silent until this player spends ammunition (or someone else
--- who needs it touches it).
+-- Duplicate HL2 weapons do not transfer ammo consistently in GMod. Handle
+-- tracked map weapons here so useful ammo is transferred exactly once, while
+-- a full player leaves the pickup available and silent for someone else.
 hook.Add("PlayerCanPickupWeapon", "CustomCoopIgnoreFullDuplicateWeapons", function(ply, weapon)
-    if not trackedItems[weapon] or not ply:HasWeapon(weapon:GetClass()) then return end
+    if not ply:HasWeapon(weapon:GetClass()) then return end
 
-    if not CanReceiveAmmo(ply, weapon:GetPrimaryAmmoType())
-        and not CanReceiveAmmo(ply, weapon:GetSecondaryAmmoType()) then
-        return false
+    local primaryAmmoType = weapon:GetPrimaryAmmoType()
+    local secondaryAmmoType = weapon:GetSecondaryAmmoType()
+
+    -- Some map logic creates weapons dynamically, so they are not part of the
+    -- map-entity tracker. A second copy of an ammo-less weapon is still always
+    -- useless and should never produce another pickup event.
+    if primaryAmmoType < 0 and secondaryAmmoType < 0 then return false end
+
+    if not trackedItems[weapon] then return end
+
+    local primaryAmount = math.max(weapon:Clip1(), 0)
+    if primaryAmount == 0 then
+        primaryAmount = cliplessWeaponAmmo[weapon:GetClass()] or 0
     end
+
+    local given = 0
+    if primaryAmmoType >= 0 and primaryAmount > 0 then
+        given = given + (ply:GiveAmmo(primaryAmount, primaryAmmoType) or 0)
+    end
+
+    local secondaryAmount = math.max(weapon:Clip2(), 0)
+    if secondaryAmmoType >= 0 and secondaryAmount > 0 then
+        given = given + (ply:GiveAmmo(secondaryAmount, secondaryAmmoType) or 0)
+    end
+
+    -- Handle the duplicate ourselves. The native path is inconsistent for
+    -- HL2 weapons under GMod: it may drain or hide the entity without giving
+    -- usable reserve ammo. Removing only after GiveAmmo succeeds also makes a
+    -- full pickup silent and leaves it available to another player.
+    if given > 0 then
+        SafeRemoveEntityDelayed(weapon, 0)
+    end
+
+    return false
 end)
 
 -- Stock ammo items normally reject a full player themselves. Checking here as