From 9f2f619a21ea1a04e346426368839f189b5e11f3 Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Tue, 14 Oct 2025 13:00:28 +0300
Subject: [PATCH] Adds hash support for Vector2, Vector3, and Vector4

Implements `std::hash` specialization for `omath::Vector2`, `omath::Vector3`, and `omath::Vector4` with float components.

This enables usage of these vector types as keys in hash-based containers, such as `std::unordered_map` and `std::unordered_set`.
---
 include/omath/linear_algebra/vector2.hpp | 15 +++++++++++++++
 include/omath/linear_algebra/vector3.hpp |  1 +
 include/omath/linear_algebra/vector4.hpp | 16 ++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/include/omath/linear_algebra/vector2.hpp b/include/omath/linear_algebra/vector2.hpp
index 4dc96c7..2994144 100644
--- a/include/omath/linear_algebra/vector2.hpp
+++ b/include/omath/linear_algebra/vector2.hpp
@@ -234,6 +234,21 @@ namespace omath
     };
 } // namespace omath
 
+template<> struct std::hash<omath::Vector2<float>>
+{
+    [[nodiscard]]
+    std::size_t operator()(const omath::Vector2<float>& vec) const noexcept
+    {
+        std::size_t hash = 0;
+        constexpr std::hash<float> hasher;
+
+        hash ^= hasher(vec.x) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+        hash ^= hasher(vec.y) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+
+        return hash;
+    }
+};
+
 template<class Type>
 struct std::formatter<omath::Vector2<Type>> // NOLINT(*-dcl58-cpp)
 {
diff --git a/include/omath/linear_algebra/vector3.hpp b/include/omath/linear_algebra/vector3.hpp
index 7e5838f..77d60cf 100644
--- a/include/omath/linear_algebra/vector3.hpp
+++ b/include/omath/linear_algebra/vector3.hpp
@@ -273,6 +273,7 @@ namespace omath
 
 template<> struct std::hash<omath::Vector3<float>>
 {
+    [[nodiscard]]
     std::size_t operator()(const omath::Vector3<float>& vec) const noexcept
     {
         std::size_t hash = 0;
diff --git a/include/omath/linear_algebra/vector4.hpp b/include/omath/linear_algebra/vector4.hpp
index d1e1377..25d6a6d 100644
--- a/include/omath/linear_algebra/vector4.hpp
+++ b/include/omath/linear_algebra/vector4.hpp
@@ -202,6 +202,22 @@ namespace omath
 };
 } // namespace omath
 
+template<> struct std::hash<omath::Vector4<float>>
+{
+    [[nodiscard]]
+    std::size_t operator()(const omath::Vector4<float>& vec) const noexcept
+    {
+        std::size_t hash = 0;
+        constexpr std::hash<float> hasher;
+
+        hash ^= hasher(vec.x) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+        hash ^= hasher(vec.y) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+        hash ^= hasher(vec.z) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+        hash ^= hasher(vec.w) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+        return hash;
+    }
+};
+
 template<class Type>
 struct std::formatter<omath::Vector4<Type>> // NOLINT(*-dcl58-cpp)
 {