Half-Life WeaponMod

This is a fork of WeaponMod with support for new GameDLL versions (8308+) and BugfixedHL-Rebased.

Differences from upstream

• Offsets are loaded from AMX Mod X instead of being hardcoded.
  • VTable offsets now use AMXX's game config system (amxmodx/data/gamedata).
• Support for latest version of HLDM.
• ReHLDS support (currently requires custom patch, see below).

Requirements

• AMX Mod X 1.10+
• ReHLDS on Linux
  • It must support GetDispatch hook. See below. No longer required.

Supported games

The module currently supports the following games. Pull requests with other games and mods are welcome.

• Half-Life Deathmatch [Windows & Linux]
  • Windows requires BugfixedHL-Rebased
  • Linux requires ReHLDS

ReHLDS support

This version supports official ReHLDS release on Windows and Linux.

Credits

• Original module by KORD_12.7 & AGHL.ru Dev Team
• AGHL.ru link
• Upstream SVN repo / Git mirror
• 8308 fix by @rtxa (before gamedata support was added)

Adding mod support

This guide provides some of the steps to add support for mods to WeaponMod. It will mostly focus on adding support for Linux (since there are absolutely no reasons to run servers on Windows).

Prerequisites

• The mod's game DLL (.so) must be compiled with debug information.
• The mod must be compiled with a modern version of GCC (4.6+) or Clang.

GameData

WeaponMod uses AMXX 1.9's new "game config" feature. It allows plugins and modules to read various offsets from a centralized mod-specific config file instead of hardcoding them. WeaponMod's config is located in amxmodx/data/gamedata/weaponmod.games. This directory will later be refered to as weaponmod.games.

In this guide you will need to make copies of files in valve for your mod.

1. Open amxmodx/data/gamedata/weaponmod.games
2. Create directory with you mod name: yourmod
3. Open master.games.txt
4. Create a comment with your mod's full name (like for HLDM).
5. For any file you create you need to add a record in master.games.txt.

Selecting reference entities

You need to select a reference weapon and a reference ammo box. WeaponMod will use them as bases for custom weapons. Most mods can use weapon_crowbar and ammo_rpgclip.

1. Copy weaponmod.games/valve/settings.txt to weaponmod.games/yourmod/settings.txt.
2. Change reference entities.
3. Add the file to weaponmod.games/master.games.txt

Generating entity offsets

Basically, you need to generate amxmodx/data/gamedata/common.games/entities.games for your mod. It seems that AMXX devs used some private tool for that. You can copy files from valve and hope for the best.

You may try to parse the output from pahole tool (reference).

Generating VTable offsets

Same as previous, but for amxmodx/data/gamedata/common.games/virtual.games.

Getting Weapon and Ammo VTable offsets

These offsets are not provided by AMXX and you will have to get them yourself.

You need to get VTable offsets for classes CBasePlayerWeapon and CBasePlayerItem.

Via pahole

1. Install pahole on Linux.
2. Pipe the output into a file. Ignore "not supported" messages.

   pahole ./hl.so > hl.so.symbols

3. Open the file. Find substring class EntityClassName :

   class CBasePlayerWeapon : public CBasePlayerItem {
   public:
   
       /* class CBasePlayerItem     <ancestor>; */      /*     0   140 */
       virtual int Save(class CBasePlayerWeapon *, class CSave &);
   
       virtual int Restore(class CBasePlayerWeapon *, class CRestore &);

4. Scroll down to /* vtable has XX entries:. There's the VTable with offsets Note that it isn't sorted (for some reason).

   [3] = Save((null)), 
   [4] = Restore((null)), 
   [58] = AddToPlayer((null)), 
   [59] = AddDuplicate((null)), 
   [76] = ExtractAmmo((null)), 
   [77] = ExtractClipAmmo((null)), 
   [78] = AddWeapon((null)), 
   [65] = UpdateItemInfo((null)), 
   [79] = PlayEmptySound((null)), 
   [80] = ResetEmptySound((null)), 
   [81] = SendWeaponAnim((null)), 
   [61] = CanDeploy((null)), 
   [82] = IsUseable((null)), 
   [67] = ItemPostFrame((null)), 
   [83] = PrimaryAttack((null)), 
   [84] = SecondaryAttack((null)), 
   [85] = Reload((null)), 
   [86] = WeaponIdle((null)), 
   [73] = UpdateClientData((null)), 
   [87] = RetireWeapon((null)), 
   [88] = ShouldWeaponIdle((null)), 
   [64] = Holster((null)), 
   [89] = UseDecrement((null)), 
   [71] = PrimaryAmmoIndex((null)), 
   [72] = SecondaryAmmoIndex((null)), 
   [74] = GetWeaponPtr((null)), 

Via gdb

We will use gdb to print vtable as an array and then use line numbers as offsets.

1. Install gdb on Linux.
2. Open the Game DLL with GDB: gdb ./hl.so
3. Type in GDB console (replace EntityClassName with class name):

   set pagination off
   set print array on
   print *(int**)&'vtable for EntityClassName'@100
   

4. You will get 100 lines of array items. Copy them to a text editor that shows line numbers (e.g. VS Code, Notepad++).

   1. $1 =   {0x0,
   2. 0x1bba10 <typeinfo for CBasePlayerWeapon>,
   3. 0x58738 <CBaseEntity::Spawn()>,
   4. 0x5874c <CBaseEntity::Precache()>,
   5. 0x129fc8 <CBaseDelay::KeyValue(KeyValueData_s*)>,
   6. 0x149f2c <CBasePlayerWeapon::Save(CSave&)>,
   7. 0x149f8c <CBasePlayerWeapon::Restore(CRestore&)>,
   8. 0x533e4 <CBaseEntity::ObjectCaps()>,
   ...
   

5. Remove first 3 lines (0x0, typeinfo and the next element)

   1. 0x5874c <CBaseEntity::Precache()>,
   2. 0x129fc8 <CBaseDelay::KeyValue(KeyValueData_s*)>,
   3. 0x149f2c <CBasePlayerWeapon::Save(CSave&)>,
   4. 0x149f8c <CBasePlayerWeapon::Restore(CRestore&)>,
   6. 0x533e4 <CBaseEntity::ObjectCaps()>,
   ...
   

6. Find the functions by their names in the text editor. Line number will be the "linux" offset.
7. As far as I know, Linux vtable offset should match Windows so put the same number for "windows".