Introduced game material system versioning helpers (#392)

This will be used to determine the specific version of gamemtl.xr being
used (e.g. SOC, or older builds)

src/xrMaterialSystem/GameMtlLib.cpp

@@ -173,10 +173,10 @@ void CGameMtlLibrary::Load()
     IReader& fs = *F;
 
     R_ASSERT(fs.find_chunk(GAMEMTLS_CHUNK_VERSION));
-    const u16 version = fs.r_u16();
-    if (GAMEMTL_CURRENT_VERSION != version)
+    m_version = static_cast<EGameMtlVersion>(fs.r_u16());
+    if (GAMEMTL_CURRENT_VERSION != m_version)
     {
-        Log("CGameMtlLibrary: invalid version. Library can't load.");
+        Msg("CGameMtlLibrary: unsupported version [%u]. Library can't load.", m_version);
         FS.r_close(F);
         return;
     }

src/xrMaterialSystem/GameMtlLib.h

@@ -14,8 +14,6 @@
 #define MTL_EXPORT_API XR_IMPORT
 #endif
 
-constexpr u16 GAMEMTL_CURRENT_VERSION     = 0x0001;
-
 constexpr u32 GAMEMTLS_CHUNK_VERSION      = 0x1000;
 constexpr u32 GAMEMTLS_CHUNK_AUTOINC      = 0x1001;
 constexpr u32 GAMEMTLS_CHUNK_MTLS         = 0x1002;
@@ -46,6 +44,22 @@ constexpr u32 GAMEMTL_NONE_IDX            = u16(-1);
 
 constexpr pcstr GAMEMTL_FILENAME          = "gamemtl.xr";
 
+enum EGameMtlVersion : u16
+{
+    // The big issue is that GSC had version 1 in SOC,
+    // then they introduced a significant change in CS,
+    // but didn't change the version number...
+    // In fact, they NEVER have changed the number
+    // since the system was introduced in 2002.
+    // So, we introduce helper values:
+    GAMEMTL_VERSION_SOC     = u16(-1),
+
+    GAMEMTL_VERSION_UNKNOWN = 0,
+
+    // Real version numbers in GAMEMTL_FILENAME:
+    GAMEMTL_CURRENT_VERSION = 1,
+};
+
 // fwd. decl.
 class IReader;
 class IWriter;
@@ -233,6 +247,7 @@ class MTL_EXPORT_API CGameMtlLibrary
     GameMtlPairVec material_pairs_rt;
 
     u32 m_file_age{};
+    EGameMtlVersion m_version{};
 
 public:
     CGameMtlLibrary();