1 files changed, 23 insertions, 0 deletions
diff --git a/src/math/utils.hpp b/src/math/utils.hpp
index 5c8c62d..ac19ddc 100644
--- a/src/math/utils.hpp
+++ b/src/math/utils.hpp
@@ -3,6 +3,7 @@
 
 #include <array>
 #include <utility>
+#include <concepts>
 #include "math/vector.hpp"
 
 namespace engine::math {
@@ -35,6 +36,28 @@ constexpr float map(float x, float from1, float from2, float to1, float to2) {
     return to1 + (x - from1) * (to2 - to1) / (from2 - from1);
 }
 
+template<typename UInt>
+constexpr UInt log2_floored(UInt n) noexcept
+requires std::same_as<UInt, unsigned> || std::same_as<UInt, unsigned long> || std::same_as<UInt, unsigned long long>
+{
+#ifdef __GNUG__
+    if constexpr (std::is_same_v<UInt, unsigned>) {
+        return static_cast<UInt>(sizeof(UInt) * 8 - 1) - __builtin_clz(n);
+    } else if constexpr (std::is_same_v<UInt, unsigned long>) {
+        return static_cast<UInt>(sizeof(UInt) * 8 - 1) - __builtin_clzl(n);
+    } else { // unsigned long long
+        return static_cast<UInt>(sizeof(UInt) * 8 - 1) - __builtin_clzll(n);
+    }
+#else
+    UInt ret = 0;
+    while (n & 1) {
+        n >>= 1;
+        ret++;
+    }
+    return ret;
+#endif
+}
+
 }
 
 #endif // MATH_UTILS_HPP