xash3d-fwgs/Documentation/mod-porting-guide.md

Self-made port

Compatibility with RISC architectures

Unaligned access

Unaligned access on i386 causes only performance penalty, but on RISC it can cause unstable work.

For HLSDK at least you need such patches in util.cpp:

• 7bfefe86e3
• 617d75545f

Signed chars

char type defined as signed for x86 and as unsigned for arm.

And sometimes such difference can break logic.

As a solution you can use signed char type in code directly or use -fsigned-char option for gcc/clang compilers.

For HLSDK at least you need such fix in nodes.cpp/.h.

Compatibility with 64bit architectures

You need list of patches for Studio Model Render, MAKE_STRING macro and nodes:

• d287ed4463
• 3bce17e3a0
• 9ebfc98177
• 00833188da
• 4661b5c1a5
• 2b61380146
• 8ef6cb2427

Mobility API

Xash3D FWGS has special extended interface in mobility_int.h which adds some new features like vibration on mobile platforms.

Porting server-side code

Original valve's server code was compatible with linux and gcc 2.x.

Newer gcc versions have restriction which breaks build.

Now, to make it building with gcc 4.x+ or clang, you need to do following:

• Go to cbase.h and redefine macros as following

#define SetThink( a ) m_pfnThink = static_cast <void (CBaseEntity::*)(void)> (&a)
#define SetTouch( a ) m_pfnTouch = static_cast <void (CBaseEntity::*)(CBaseEntity *)> (&a)
#define SetUse( a ) m_pfnUse = static_cast <void (CBaseEntity::*)( CBaseEntity *pActivator, CBaseEntity *pCaller, USE_TYPE useType, float value )> (&a)
#define SetBlocked( a ) m_pfnBlocked = static_cast <void (CBaseEntity::*)(CBaseEntity *)> (&a)
#define ResetThink( ) m_pfnThink = static_cast <void (CBaseEntity::*)(void)> (NULL)
#define ResetTouch( ) m_pfnTouch = static_cast <void (CBaseEntity::*)(CBaseEntity *)> (NULL)
#define ResetUse( ) m_pfnUse = static_cast <void (CBaseEntity::*)( CBaseEntity *pActivator, CBaseEntity *pCaller, USE_TYPE useType, float value )> (NULL)
#define ResetBlocked( ) m_pfnBlocked = static_cast <void (CBaseEntity::*)(CBaseEntity *)> (NULL)
...
#define SetMoveDone( a ) m_pfnCallWhenMoveDone = static_cast <void (CBaseToggle::*)(void)> (&a)

• Replace all SetThink(NULL), SetTouch(NULL), setUse(NULL) and SetBlocked(NULL) by ResetThink(), ResetTouch(), ResetUse() and ResetBlocked()
• Sometimes you may need to add #include <ctype.h> if functions tolower or isspace are missing

Porting client-side code

• Redefine all DLLEXPORT defines as empty field (Place it under _WIN32 macro if you want to keep windows compatibility).
• Remove hud_servers.cpp and Servers_Init/Servers_Shutdown from hud.cpp.
• Fix CAPS filenames in includes (like STDIO.H, replace by stdio.h).
• Replace broken macros as DECLARE_MESSAGE, DECLARE_COMMAND by fixed examples from our hlsdk-portable port (cl_util.h).
• Add ctype.h where is needed (tolower, isspace functions).
• Add string.h where is needed (memcpy, strcpy, etc).
• Use in_defs.h from hlsdk-portable.
• Add input_xash3d.cpp from hlsdk-portable project to fix input.

Now your client should be able to build and work correctly.

Porting mod to hlsdk-portable

Look at changes which was made.

If there are not too much changes (for example, only some weapons was added), add these changes in hlsdk-portable.

You can use diff with original HLSDK and apply it as patch to hlsdk-portable.

NOTE: Many an old mods was made on HLSDK 2.0-2.1 and some rare mods on HLSDK 1.0.
So you need to have different versions of HLSDK to make diffs.
Plus different Spirit of Half-Life versions if mod was made on it.
Also, weapons in old HLSDK versions does not use client weapon prediction system and you may be need to port standart half-life weapons to server side.

Files must have same line endings (use dos2unix on all files).

We recommend to enable ignoring space changes in diff.

Move all new files to separate directories.

Possible replacements for non-portable external dependencies

1. If mod uses fmod.dll or base.dll to play mp3/ogg on client-side or to precache sounds on server-side, you can replace it with:

   • pfnPrimeMusicStream engine callback;
   • miniaudio;
   • phonon.

2. If mod uses OpenGL, porting code to Xash3D render interface is recommended.

3. If mod uses cg.dll, you can try to port code to NVFX.

4. If mod uses detours, comment code or try to find replacement somehow by yourself.

Additional recommendations

1. If mod uses STL, you can replace it with MiniUTL.
2. Avoid to use dynamic casts to make small size binaries.
3. Avoid to use exceptions to make small size binaries.

Writing build scripts

Use wscript/CMakeLists.txt files from hlsdk-portable as build scripts example.

Get .c and .cpp file lists from Visual Studio project.

Add missing include dirs.