6 files changed, 49 insertions, 23 deletions
diff --git a/Source/Core/Common/CommonPaths.h b/Source/Core/Common/CommonPaths.h
index 474890c4d8..4fa4b4f34a 100644
--- a/Source/Core/Common/CommonPaths.h
+++ b/Source/Core/Common/CommonPaths.h
@@ -92,6 +92,7 @@
 #define WIISDSYNC_DIR "WiiSDSync"
 #define ASSEMBLY_DIR "SavedAssembly"
 #define WIIBANNERS_DIR "WiiBanners"
+#define SOUNDS_DIR "Sounds"
 
 // This one is only used to remove it if it was present
 #define SHADERCACHE_LEGACY_DIR "ShaderCache"
diff --git a/Source/Core/Common/FileUtil.cpp b/Source/Core/Common/FileUtil.cpp
index ba52f63094..50d6b036f4 100644
--- a/Source/Core/Common/FileUtil.cpp
+++ b/Source/Core/Common/FileUtil.cpp
@@ -915,6 +915,7 @@ static void RebuildUserDirectories(unsigned int dir_index)
     s_user_paths[F_GBABIOS_IDX] = s_user_paths[D_GBAUSER_IDX] + GBA_BIOS;
 
     s_user_paths[D_ASM_ROOT_IDX] = s_user_paths[D_USER_IDX] + ASSEMBLY_DIR DIR_SEP;
+    s_user_paths[D_SOUNDS_IDX] = s_user_paths[D_LOAD_IDX] + SOUNDS_DIR DIR_SEP;
 
     // The shader cache has moved to the cache directory, so remove the old one.
     // TODO: remove that someday.
@@ -975,6 +976,7 @@ static void RebuildUserDirectories(unsigned int dir_index)
     s_user_paths[D_DYNAMICINPUT_IDX] = s_user_paths[D_LOAD_IDX] + DYNAMICINPUT_DIR DIR_SEP;
     s_user_paths[D_GRAPHICSMOD_IDX] = s_user_paths[D_LOAD_IDX] + GRAPHICSMOD_DIR DIR_SEP;
     s_user_paths[D_BANNERS_WIIROOT_IDX] = s_user_paths[D_LOAD_IDX] + WIIBANNERS_DIR DIR_SEP;
+    s_user_paths[D_SOUNDS_IDX] = s_user_paths[D_LOAD_IDX] + SOUNDS_DIR DIR_SEP;
     break;
   }
 }
diff --git a/Source/Core/Common/FileUtil.h b/Source/Core/Common/FileUtil.h
index d5c8285305..9cb5fb7040 100644
--- a/Source/Core/Common/FileUtil.h
+++ b/Source/Core/Common/FileUtil.h
@@ -77,6 +77,7 @@ enum
   D_GPU_DRIVERS_FILE_REDIRECT,
   D_ASM_ROOT_IDX,
   D_BANNERS_WIIROOT_IDX,
+  D_SOUNDS_IDX,
   FIRST_FILE_USER_PATH_IDX,
   F_DOLPHINCONFIG_IDX = FIRST_FILE_USER_PATH_IDX,
   F_GCPADCONFIG_IDX,
diff --git a/Source/Core/Common/MathUtil.h b/Source/Core/Common/MathUtil.h
index 47440f2239..939d31b97a 100644
--- a/Source/Core/Common/MathUtil.h
+++ b/Source/Core/Common/MathUtil.h
@@ -8,15 +8,18 @@
 #include <cmath>
 #include <concepts>
 #include <limits>
+#include <numbers>
 #include <type_traits>
 #include <utility>
 
+#include "Common/Assert.h"
 #include "Common/CommonTypes.h"
 
 namespace MathUtil
 {
-constexpr double TAU = 6.2831853071795865;
-constexpr double PI = TAU / 2;
+template <std::floating_point T>
+constexpr T TAU_v = std::numbers::pi_v<T> * 2;
+constexpr double TAU = TAU_v<double>;
 constexpr double GRAVITY_ACCELERATION = 9.80665;
 
 template <typename T>
@@ -25,12 +28,6 @@ constexpr auto Sign(const T& val) -> decltype((T{} < val) - (val < T{}))
   return (T{} < val) - (val < T{});
 }
 
-template <typename T, typename F>
-constexpr auto Lerp(const T& x, const T& y, const F& a) -> decltype(x + (y - x) * a)
-{
-  return x + (y - x) * a;
-}
-
 // Casts the specified value to a Dest. The value will be clamped to fit in the destination type.
 // Warning: The result of SaturatingCast(NaN) is undefined.
 template <std::integral Dest, typename T>
@@ -56,23 +53,21 @@ constexpr Dest SaturatingCast(T value)
   return static_cast<Dest>(value);
 }
 
-template <typename T>
+template <std::integral T>
 constexpr bool IsPow2(T imm)
 {
-  return imm > 0 && (imm & (imm - 1)) == 0;
+  if constexpr (std::is_signed_v<T>)
+  {
+    if (imm <= 0)
+      return false;
+  }
+
+  return std::has_single_bit(static_cast<std::make_unsigned_t<T>>(imm));
 }
 
 constexpr u32 NextPowerOf2(u32 value)
 {
-  --value;
-  value |= value >> 1;
-  value |= value >> 2;
-  value |= value >> 4;
-  value |= value >> 8;
-  value |= value >> 16;
-  ++value;
-
-  return value;
+  return std::bit_ceil(value);
 }
 
 template <class T>
@@ -173,6 +168,20 @@ private:
 // Rounds down. 0 -> undefined
 constexpr int IntLog2(u64 val)
 {
-  return 63 - std::countl_zero(val);
+  DEBUG_ASSERT(val != 0);
+  return std::bit_width(val) - 1;
 }
+
+template <std::floating_point T>
+constexpr T DegreesToRadians(T degrees)
+{
+  return degrees * std::numbers::pi_v<T> / T(180);
+}
+
+template <std::floating_point T>
+constexpr T RadiansToDegrees(T radians)
+{
+  return radians / std::numbers::pi_v<T> * T(180);
+}
+
 }  // namespace MathUtil
diff --git a/Source/Core/Common/Matrix.cpp b/Source/Core/Common/Matrix.cpp
index 9c75487111..92de573f87 100644
--- a/Source/Core/Common/Matrix.cpp
+++ b/Source/Core/Common/Matrix.cpp
@@ -4,8 +4,7 @@
 #include "Common/Matrix.h"
 
 #include <cmath>
-
-#include "Common/MathUtil.h"
+#include <numbers>
 
 namespace
 {
@@ -136,7 +135,7 @@ Vec3 FromQuaternionToEuler(const Quaternion& q)
 
   const float sinp = 2 * (qw * qy - qz * qx);
   if (std::abs(sinp) >= 1)
-    result.y = std::copysign(MathUtil::PI / 2, sinp);  // use 90 degrees if out of range
+    result.y = std::copysign(std::numbers::pi / 2, sinp);  // use 90 degrees if out of range
   else
     result.y = std::asin(sinp);
 
diff --git a/Source/Core/Common/Matrix.h b/Source/Core/Common/Matrix.h
index 9aafd1bf83..b7de819934 100644
--- a/Source/Core/Common/Matrix.h
+++ b/Source/Core/Common/Matrix.h
@@ -37,6 +37,10 @@ union TVec3
   constexpr T LengthSquared() const { return Dot(*this); }
   T Length() const { return std::sqrt(LengthSquared()); }
   TVec3 Normalized() const { return *this / Length(); }
+  static constexpr TVec3<T> Lerp(const TVec3<T>& a, const TVec3<T>& b, const TVec3<T>& t)
+  {
+    return {std::lerp(a.x, b.x, t.x), std::lerp(a.y, b.y, t.y), std::lerp(a.z, b.z, t.z)};
+  }
 
   constexpr TVec3& operator+=(const TVec3& rhs)
   {
@@ -163,6 +167,16 @@ union TVec4
     return x == other.x && y == other.y && z == other.z && w == other.w;
   }
 
+  static constexpr TVec4<T> Lerp(const TVec4<T>& a, const TVec4<T>& b, const TVec4<T>& t)
+  {
+    return {
+        std::lerp(a.x, b.x, t.x),
+        std::lerp(a.y, b.y, t.y),
+        std::lerp(a.z, b.z, t.z),
+        std::lerp(a.w, b.w, t.w),
+    };
+  }
+
   constexpr T Dot(const TVec4& other) const
   {
     return x * other.x + y * other.y + z * other.z + w * other.w;