Sampler state caching.

src/xenia/types.h

@@ -134,6 +134,16 @@ typedef XECACHEALIGN volatile void xe_aligned_void_t;
 #endif  // GNUC
 #endif  // !MIN
 
+XEFORCEINLINE size_t hash_combine(size_t seed) {
+  return seed;
+}
+template <typename T, typename... Ts>
+size_t hash_combine(size_t seed, const T& v, const Ts&... vs) {
+  std::hash<T> hasher;
+  seed ^= hasher(v) + 0x9E3779B9 + (seed << 6) + (seed >> 2);
+  return hash_combine(seed, vs...);
+}
+
 #if XE_PLATFORM_WIN32
 #define XESAFERELEASE(p)        if (p) { p->Release(); }
 #endif  // WIN32