patch

.github/workflows/cmake-multi-platform.yml

@@ -107,7 +107,7 @@ jobs:
             -DOMATH_BUILD_TESTS=ON \
             -DOMATH_BUILD_BENCHMARK=OFF \
             -DOMATH_ENABLE_COVERAGE=${{ matrix.coverage == true && 'ON' || 'OFF' }} \
-            -DVCPKG_MANIFEST_FEATURES="imgui;avx2;tests;lua"
+            -DVCPKG_MANIFEST_FEATURES="imgui;avx2;tests;lua;gcem"
 
       - name: Build
         shell: bash

CMakeLists.txt

@@ -33,6 +33,7 @@ option(OMATH_ENABLE_FORCE_INLINE
 option(OMATH_ENABLE_LUA
         "omath bindings for lua" OFF)
 option(OMATH_ENABLE_HOOKING "omath will HooksManager that can hook DirectX/OpenGL automatically" OFF)
+option(OMATH_USE_GCEM "omath will use gcem library to make more functions/methods constexpr" OFF)
 
 if(VCPKG_MANIFEST_FEATURES)
     foreach(omath_feature IN LISTS VCPKG_MANIFEST_FEATURES)
@@ -50,6 +51,8 @@ if(VCPKG_MANIFEST_FEATURES)
             set(OMATH_ENABLE_LUA ON)
         elseif(omath_feature STREQUAL "hooking")
             set(OMATH_ENABLE_HOOKING ON)
+        elseif (omath_feature STREQUAL "gcem")
+            set(OMATH_USE_GCEM ON)
         endif()
 
     endforeach()
@@ -80,6 +83,7 @@ if(${PROJECT_IS_TOP_LEVEL})
     message(STATUS "[${PROJECT_NAME}]: Coverage feature status ${OMATH_ENABLE_COVERAGE}")
     message(STATUS "[${PROJECT_NAME}]: Valgrind feature status ${OMATH_ENABLE_VALGRIND}")
     message(STATUS "[${PROJECT_NAME}]: Lua feature status ${OMATH_ENABLE_LUA}")
+    message(STATUS "[${PROJECT_NAME}]: Gcem feature status ${OMATH_USE_GCEM}")
 endif()
 
 if(OMATH_STATIC_MSVC_RUNTIME_LIBRARY)
@@ -120,6 +124,12 @@ if (OMATH_ENABLE_HOOKING)
     endif ()
 endif ()
 
+
+if (OMATH_USE_GCEM)
+    target_compile_definitions(${PROJECT_NAME} PUBLIC OMATH_USE_GCEM)
+    find_package(gcem CONFIG REQUIRED)
+    target_link_libraries(${PROJECT_NAME} PUBLIC gcem)
+endif ()
 add_library(${PROJECT_NAME}::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
 
 target_compile_definitions(${PROJECT_NAME} PUBLIC OMATH_VERSION="${PROJECT_VERSION}")

CMakePresets.json

@@ -57,7 +57,7 @@
       "inherits": ["windows-base", "vcpkg-base"],
       "cacheVariables": {
         "VCPKG_TARGET_TRIPLET": "x64-windows-static",
-        "VCPKG_MANIFEST_FEATURES": "tests;imgui;avx2;examples;hooking",
+        "VCPKG_MANIFEST_FEATURES": "tests;imgui;avx2;examples;hooking;gcem",
         "OMATH_STATIC_MSVC_RUNTIME_LIBRARY": "ON"
       }
     },
@@ -239,7 +239,7 @@
       "hidden": true,
       "inherits": ["darwin-base", "vcpkg-base"],
       "cacheVariables": {
-        "VCPKG_MANIFEST_FEATURES": "tests;imgui;avx2;examples;lua"
+        "VCPKG_MANIFEST_FEATURES": "tests;imgui;avx2;examples;lua;gcem"
       }
     },
     {

include/omath/engines/cry_engine/formulas.hpp

@@ -8,31 +8,81 @@
 namespace omath::cry_engine
 {
     [[nodiscard]]
-    Vector3<float> forward_vector(const ViewAngles& angles) noexcept;
+    inline OMATH_CONSTEXPR Mat4X4 rotation_matrix(const ViewAngles& angles) noexcept
+    {
+        return mat_rotation_axis_z<float, MatStoreType::ROW_MAJOR>(angles.yaw)
+               * mat_rotation_axis_y<float, MatStoreType::ROW_MAJOR>(angles.roll)
+               * mat_rotation_axis_x<float, MatStoreType::ROW_MAJOR>(angles.pitch);
+    }
 
     [[nodiscard]]
-    Vector3<float> right_vector(const ViewAngles& angles) noexcept;
+    inline OMATH_CONSTEXPR Vector3<float> forward_vector(const ViewAngles& angles) noexcept
+    {
+        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_forward);
+
+        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
+    }
 
     [[nodiscard]]
-    Vector3<float> up_vector(const ViewAngles& angles) noexcept;
+    inline OMATH_CONSTEXPR Vector3<float> right_vector(const ViewAngles& angles) noexcept
+    {
+        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_right);
 
-    [[nodiscard]] Mat4X4 calc_view_matrix(const ViewAngles& angles, const Vector3<float>& cam_origin) noexcept;
+        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
+    }
 
     [[nodiscard]]
-    Mat4X4 rotation_matrix(const ViewAngles& angles) noexcept;
+    inline OMATH_CONSTEXPR Vector3<float> up_vector(const ViewAngles& angles) noexcept
+    {
+        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_up);
+
+        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
+    }
 
     [[nodiscard]]
-    Vector3<float> extract_origin(const Mat4X4& mat) noexcept;
+    inline OMATH_CONSTEXPR Mat4X4 calc_view_matrix(const ViewAngles& angles, const Vector3<float>& cam_origin) noexcept
+    {
+        return mat_camera_view<float, MatStoreType::ROW_MAJOR>(forward_vector(angles), right_vector(angles),
+                                                               up_vector(angles), cam_origin);
+    }
 
     [[nodiscard]]
-    Vector3<float> extract_scale(const Mat4X4& mat) noexcept;
+    inline OMATH_CONSTEXPR Vector3<float> extract_origin(const Mat4X4& mat) noexcept
+    {
+        return mat_extract_origin(mat);
+    }
 
     [[nodiscard]]
-    ViewAngles extract_rotation_angles(const Mat4X4& mat) noexcept;
+    inline OMATH_CONSTEXPR Vector3<float> extract_scale(const Mat4X4& mat) noexcept
+    {
+        return mat_extract_scale(mat);
+    }
 
     [[nodiscard]]
-    Mat4X4 calc_perspective_projection_matrix(float field_of_view, float aspect_ratio, float near, float far,
+    inline OMATH_CONSTEXPR ViewAngles extract_rotation_angles(const Mat4X4& mat) noexcept
-                                             NDCDepthRange ndc_depth_range = NDCDepthRange::ZERO_TO_ONE) noexcept;
+    {
+        const auto angles = mat_extract_rotation_zyx(mat);
+        return {
+                PitchAngle::from_degrees(angles.x),
+                YawAngle::from_degrees(angles.z),
+                RollAngle::from_degrees(angles.y),
+        };
+    }
+    [[nodiscard]]
+    inline OMATH_CONSTEXPR Mat4X4 calc_perspective_projection_matrix(
+            const float field_of_view, const float aspect_ratio, const float near, const float far,
+            const NDCDepthRange ndc_depth_range = NDCDepthRange::ZERO_TO_ONE) noexcept
+    {
+        if (ndc_depth_range == NDCDepthRange::ZERO_TO_ONE)
+            return mat_perspective_left_handed_vertical_fov<float, MatStoreType::ROW_MAJOR, NDCDepthRange::ZERO_TO_ONE>(
+                    field_of_view, aspect_ratio, near, far);
+
+        if (ndc_depth_range == NDCDepthRange::NEGATIVE_ONE_TO_ONE)
+            return mat_perspective_left_handed_vertical_fov<float, MatStoreType::ROW_MAJOR,
+                                                            NDCDepthRange::NEGATIVE_ONE_TO_ONE>(
+                    field_of_view, aspect_ratio, near, far);
+        std::unreachable();
+    }
 
     template<class FloatingType>
     requires std::is_floating_point_v<FloatingType>

include/omath/engines/cry_engine/traits/camera_trait.hpp

@@ -4,21 +4,41 @@
 
 #pragma once
 #include "omath/engines/cry_engine/formulas.hpp"
+#include "omath/internal/optional_constexpr_math.hpp"
 #include "omath/projection/camera.hpp"
-
 namespace omath::cry_engine
 {
     class CameraTrait final
     {
     public:
         [[nodiscard]]
-        static ViewAngles calc_look_at_angle(const Vector3<float>& cam_origin, const Vector3<float>& look_at) noexcept;
+        OMATH_CONSTEXPR static ViewAngles calc_look_at_angle(const Vector3<float>& cam_origin,
+                                                             const Vector3<float>& look_at) noexcept
+        {
+            const auto direction = (look_at - cam_origin).normalized();
+#ifdef OMATH_USE_GCEM
+            return {PitchAngle::from_radians(gcem::asin(direction.z)),
+                    YawAngle::from_radians(-gcem::atan2(direction.x, direction.y)), RollAngle::from_radians(0.f)};
+#else
+            return {PitchAngle::from_radians(std::asin(direction.z)),
+                    YawAngle::from_radians(-std::atan2(direction.x, direction.y)), RollAngle::from_radians(0.f)};
+#endif
+        }
 
         [[nodiscard]]
-        static Mat4X4 calc_view_matrix(const ViewAngles& angles, const Vector3<float>& cam_origin) noexcept;
+        OMATH_CONSTEXPR static Mat4X4 calc_view_matrix(const ViewAngles& angles,
+                                                       const Vector3<float>& cam_origin) noexcept
+        {
+            return cry_engine::calc_view_matrix(angles, cam_origin);
+        }
         [[nodiscard]]
-        static Mat4X4 calc_projection_matrix(const projection::FieldOfView& fov, const projection::ViewPort& view_port,
+        OMATH_CONSTEXPR static Mat4X4
-                                             float near, float far, NDCDepthRange ndc_depth_range) noexcept;
+        calc_projection_matrix(const projection::FieldOfView& fov, const projection::ViewPort& view_port,
+                               const float near, const float far, const NDCDepthRange ndc_depth_range) noexcept
+        {
+            return calc_perspective_projection_matrix(fov.as_degrees(), view_port.aspect_ratio(), near, far,
+                                                      ndc_depth_range);
+        }
     };
 
-} // namespace omath::cry_engine
+} // namespace omath::cry_engine

include/omath/internal/optional_constexpr_math.hpp

@@ -0,0 +1,12 @@
+//
+// Created by orange on 6/11/2026.
+//
+#pragma once
+
+
+#ifdef OMATH_USE_GCEM
+#include <gcem.hpp>
+#define OMATH_CONSTEXPR constexpr
+#else
+#define OMATH_CONSTEXPR
+#endif

include/omath/linear_algebra/mat.hpp

@@ -10,6 +10,7 @@
 #include <numeric>
 #include <sstream>
 #include <stdexcept>
+#include <type_traits>
 #include <utility>
 
 #ifdef OMATH_USE_AVX2
@@ -149,7 +150,8 @@ namespace omath
             }
         }
 
-        [[nodiscard("You must use element reference")]] constexpr Type& at(const size_t row_index, const size_t column_index)
+        [[nodiscard("You must use element reference")]] constexpr Type& at(const size_t row_index,
+                                                                           const size_t column_index)
         {
             return const_cast<Type&>(std::as_const(*this).at(row_index, column_index));
         }
@@ -176,6 +178,13 @@ namespace omath
         operator*(const Mat<Columns, OtherColumns, Type, StoreType>& other) const
         {
 #ifdef OMATH_USE_AVX2
+            if (std::is_constant_evaluated())
+            {
+                if constexpr (StoreType == MatStoreType::ROW_MAJOR)
+                    return cache_friendly_multiply_row_major(other);
+                else if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)
+                    return cache_friendly_multiply_col_major(other);
+            }
             if constexpr (StoreType == MatStoreType::ROW_MAJOR)
                 return avx_multiply_row_major(other);
             else if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)
@@ -622,10 +631,14 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR>
     [[nodiscard("You must use extracted scale")]]
-    Vector3<Type> mat_extract_scale(const Mat<4, 4, Type, St>& mat) noexcept
+    OMATH_CONSTEXPR Vector3<Type> mat_extract_scale(const Mat<4, 4, Type, St>& mat) noexcept
     {
         auto column_length = [](const Type x, const Type y, const Type z) {
+#ifdef OMATH_USE_GCEM
+            return static_cast<Type>(gcem::sqrt(x * x + y * y + z * z));
+#else
             return static_cast<Type>(std::sqrt(x * x + y * y + z * z));
+#endif
         };
 
         const auto scale_x = column_length(mat.at(0, 0), mat.at(1, 0), mat.at(2, 0));
@@ -635,9 +648,15 @@ namespace omath
         constexpr auto epsilon = std::numeric_limits<Type>::epsilon();
 
         return {
+#ifdef OMATH_USE_GCEM
+                gcem::abs(scale_x) < epsilon ? Type{1} : scale_x,
+                gcem::abs(scale_y) < epsilon ? Type{1} : scale_y,
+                gcem::abs(scale_z) < epsilon ? Type{1} : scale_z,
+#else
                 std::abs(scale_x) < epsilon ? Type{1} : scale_x,
                 std::abs(scale_y) < epsilon ? Type{1} : scale_y,
                 std::abs(scale_z) < epsilon ? Type{1} : scale_z,
+#endif
         };
     }
 
@@ -654,15 +673,21 @@ namespace omath
         const auto m22 = mat.at(2, 2) / scale.z;
 
         return {
+#ifdef OMATH_USE_GCEM
+                angles::radians_to_degrees(gcem::atan2(m21, m22)),
+                angles::radians_to_degrees(gcem::asin(std::clamp(-m20, Type{-1}, Type{1}))),
+                angles::radians_to_degrees(gcem::atan2(m10, m00)),
+#else
                 angles::radians_to_degrees(std::atan2(m21, m22)),
                 angles::radians_to_degrees(std::asin(std::clamp(-m20, Type{-1}, Type{1}))),
                 angles::radians_to_degrees(std::atan2(m10, m00)),
+#endif
         };
     }
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR, class Angle>
     [[nodiscard("You must use rotation matrix")]]
-    Mat<4, 4, Type, St> mat_rotation_axis_x(const Angle& angle) noexcept
+    OMATH_CONSTEXPR Mat<4, 4, Type, St> mat_rotation_axis_x(const Angle& angle) noexcept
     {
         return
         {
@@ -675,7 +700,7 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR, class Angle>
     [[nodiscard("You must use rotation matrix")]]
-    Mat<4, 4, Type, St> mat_rotation_axis_y(const Angle& angle) noexcept
+    OMATH_CONSTEXPR Mat<4, 4, Type, St> mat_rotation_axis_y(const Angle& angle) noexcept
     {
         return
         {
@@ -688,7 +713,7 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR, class Angle>
     [[nodiscard("You must use rotation matrix")]]
-    Mat<4, 4, Type, St> mat_rotation_axis_z(const Angle& angle) noexcept
+    OMATH_CONSTEXPR Mat<4, 4, Type, St> mat_rotation_axis_z(const Angle& angle) noexcept
     {
         return
         {
@@ -701,7 +726,7 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR>
     [[nodiscard("You must use camera view matrix")]]
-    static Mat<4, 4, Type, St> mat_camera_view(const Vector3<Type>& forward, const Vector3<Type>& right,
+    OMATH_CONSTEXPR static Mat<4, 4, Type, St> mat_camera_view(const Vector3<Type>& forward, const Vector3<Type>& right,
                                                const Vector3<Type>& up, const Vector3<Type>& camera_origin) noexcept
     {
         return  Mat<4, 4, Type, St>
@@ -715,12 +740,15 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use perspective matrix")]]
+    [[nodiscard("You must use perspective matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_perspective_left_handed_vertical_fov(const Type field_of_view, const Type aspect_ratio,
                                                     const Type near, const Type far) noexcept
     {
+#ifdef OMATH_USE_GCEM
+        const auto fov_half_tan = gcem::tan(angles::degrees_to_radians(field_of_view) / Type{2});
+#else
         const auto fov_half_tan = std::tan(angles::degrees_to_radians(field_of_view) / Type{2});
-
+#endif
         if constexpr (DepthRange == NDCDepthRange::ZERO_TO_ONE)
             return {{Type{1} / (aspect_ratio * fov_half_tan), Type{0},                Type{0},             Type{0}},
                     {Type{0},                                 Type{1} / fov_half_tan, Type{0},             Type{0}},
@@ -737,11 +765,15 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use perspective matrix")]]
+    [[nodiscard("You must use perspective matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_perspective_right_handed_vertical_fov(const Type field_of_view, const Type aspect_ratio,
                                                      const Type near, const Type far) noexcept
     {
+#ifdef OMATH_USE_GCEM
+        const auto fov_half_tan = gcem::tan(angles::degrees_to_radians(field_of_view) / Type{2});
+#else
         const auto fov_half_tan = std::tan(angles::degrees_to_radians(field_of_view) / Type{2});
+#endif
 
         if constexpr (DepthRange == NDCDepthRange::ZERO_TO_ONE)
             return {{Type{1} / (aspect_ratio * fov_half_tan), Type{0},                Type{0},             Type{0}},
@@ -762,12 +794,16 @@ namespace omath
     // X and Y scales derived as: X = 1 / tan(hfov/2), Y = aspect / tan(hfov/2).
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use perspective matrix")]]
+    [[nodiscard("You must use perspective matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_perspective_left_handed_horizontal_fov(const Type horizontal_fov,
                                                                    const Type aspect_ratio, const Type near,
                                                                    const Type far) noexcept
     {
+#ifdef OMATH_USE_GCEM
+        const auto inv_tan_half_hfov = Type{1} / gcem::tan(angles::degrees_to_radians(horizontal_fov) / Type{2});
+#else
         const auto inv_tan_half_hfov = Type{1} / std::tan(angles::degrees_to_radians(horizontal_fov) / Type{2});
+#endif
         const auto x_axis = inv_tan_half_hfov;
         const auto y_axis = inv_tan_half_hfov * aspect_ratio;
 
@@ -787,12 +823,17 @@ namespace omath
 
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use perspective matrix")]]
+    [[nodiscard("You must use perspective matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_perspective_right_handed_horizontal_fov(const Type horizontal_fov,
                                                                     const Type aspect_ratio, const Type near,
                                                                     const Type far) noexcept
     {
+#ifdef OMATH_USE_GCEM
+        const auto inv_tan_half_hfov = Type{1} / gcem::tan(angles::degrees_to_radians(horizontal_fov) / Type{2});
+#else
         const auto inv_tan_half_hfov = Type{1} / std::tan(angles::degrees_to_radians(horizontal_fov) / Type{2});
+#endif
+
         const auto x_axis = inv_tan_half_hfov;
         const auto y_axis = inv_tan_half_hfov * aspect_ratio;
 
@@ -811,7 +852,7 @@ namespace omath
     }
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use ortho matrix")]]
+    [[nodiscard("You must use ortho matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_ortho_left_handed(const Type left, const Type right, const Type bottom, const Type top,
                                               const Type near, const Type far) noexcept
     {
@@ -836,7 +877,7 @@ namespace omath
     }
     template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR,
              NDCDepthRange DepthRange = NDCDepthRange::NEGATIVE_ONE_TO_ONE>
-    [[nodiscard("You must use ortho matrix")]]
+    [[nodiscard("You must use ortho matrix")]] OMATH_CONSTEXPR
     Mat<4, 4, Type, St> mat_ortho_right_handed(const Type left, const Type right, const Type bottom, const Type top,
                                                const Type near, const Type far) noexcept
     {
@@ -860,7 +901,7 @@ namespace omath
             std::unreachable();
     }
     template<class T = float, MatStoreType St = MatStoreType::COLUMN_MAJOR>
-   Mat<4, 4, T, St> mat_look_at_left_handed(const Vector3<T>& eye, const Vector3<T>& center, const Vector3<T>& up)
+    OMATH_CONSTEXPR Mat<4, 4, T, St> mat_look_at_left_handed(const Vector3<T>& eye, const Vector3<T>& center, const Vector3<T>& up)
     {
         const Vector3<T> f = (center - eye).normalized();
         const Vector3<T> s = f.cross(up).normalized();
@@ -869,7 +910,7 @@ namespace omath
     }
 
     template<class T = float, MatStoreType St = MatStoreType::COLUMN_MAJOR>
-    Mat<4, 4, T, St>mat_look_at_right_handed(const Vector3<T>& eye, const Vector3<T>& center, const Vector3<T>& up)
+    OMATH_CONSTEXPR Mat<4, 4, T, St> mat_look_at_right_handed(const Vector3<T>& eye, const Vector3<T>& center, const Vector3<T>& up)
     {
         const Vector3<T> f = (center - eye).normalized();
         const Vector3<T> s = f.cross(up).normalized();

include/omath/linear_algebra/triangle.hpp

@@ -2,8 +2,8 @@
 // Created by Orange on 11/13/2024.
 //
 #pragma once
+#include "omath/internal/optional_constexpr_math.hpp"
 #include "vector3.hpp"
-
 namespace omath
 {
     /*
@@ -40,13 +40,13 @@ namespace omath
         }
 
         [[nodiscard]]
-        Vector::ContainedType side_a_length() const
+        OMATH_CONSTEXPR Vector::ContainedType side_a_length() const
         {
             return m_vertex1.distance_to(m_vertex2);
         }
 
         [[nodiscard]]
-        Vector::ContainedType side_b_length() const
+        OMATH_CONSTEXPR Vector::ContainedType side_b_length() const
         {
             return m_vertex3.distance_to(m_vertex2);
         }
@@ -69,7 +69,11 @@ namespace omath
             const auto side_b = side_b_length();
             const auto hypot_value = hypot();
 
+#ifdef OMATH_USE_GCEM
+            return gcem::abs(side_a * side_a + side_b * side_b - hypot_value * hypot_value) <= 0.0001f;
+#else
             return std::abs(side_a * side_a + side_b * side_b - hypot_value * hypot_value) <= 0.0001f;
+#endif
         }
         [[nodiscard]]
         constexpr Vector side_b_vector() const

include/omath/linear_algebra/vector2.hpp

@@ -3,6 +3,7 @@
 //
 
 #pragma once
+#include "omath/internal/optional_constexpr_math.hpp"
 #include <cmath>
 #include <format>
 #include <tuple>
@@ -116,9 +117,13 @@ namespace omath
 
         // Basic vector operations
         [[nodiscard("You must use distance")]]
-        Type distance_to(const Vector2& other) const noexcept
+        OMATH_CONSTEXPR Type distance_to(const Vector2& other) const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::sqrt(distance_to_sqr(other));
+#else
             return std::sqrt(distance_to_sqr(other));
+#endif
         }
 
         [[nodiscard("You must use squared distance")]]
@@ -136,7 +141,11 @@ namespace omath
 #ifndef _MSC_VER
         [[nodiscard("You must use length")]] constexpr Type length() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::hypot(this->x, this->y);
+#else
             return std::hypot(this->x, this->y);
+#endif
         }
 
         [[nodiscard("You must use normalized vector")]] constexpr Vector2 normalized() const noexcept
@@ -146,13 +155,17 @@ namespace omath
         }
 #else
         [[nodiscard("You must use length")]]
-        Type length() const noexcept
+        OMATH_CONSTEXPR Type length() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::hypot(x, y);
+#else
             return std::hypot(x, y);
+#endif
         }
 
         [[nodiscard("You must use normalized vector")]]
-        Vector2 normalized() const noexcept
+        OMATH_CONSTEXPR Vector2 normalized() const noexcept
         {
             const Type len = length();
             return len > static_cast<Type>(0) ? *this / len : *this;
@@ -216,24 +229,24 @@ namespace omath
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator<(const Vector2& other) const noexcept
+        OMATH_CONSTEXPR bool operator<(const Vector2& other) const noexcept
         {
             return length() < other.length();
         }
         [[nodiscard("You must use comparison result")]]
-        bool operator>(const Vector2& other) const noexcept
+        OMATH_CONSTEXPR bool operator>(const Vector2& other) const noexcept
         {
             return length() > other.length();
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator<=(const Vector2& other) const noexcept
+        OMATH_CONSTEXPR bool operator<=(const Vector2& other) const noexcept
         {
             return length() <= other.length();
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator>=(const Vector2& other) const noexcept
+        OMATH_CONSTEXPR bool operator>=(const Vector2& other) const noexcept
         {
             return length() >= other.length();
         }

include/omath/linear_algebra/vector3.hpp

@@ -140,20 +140,24 @@ namespace omath
         }
 
 #ifndef _MSC_VER
-        [[nodiscard("You must use length")]] constexpr Type length() const
+        [[nodiscard("You must use length")]] constexpr Type length() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::sqrt(this->x * this->x + this->y * this->y + z * z);
+#else
             return std::hypot(this->x, this->y, z);
+#endif
         }
 
-        [[nodiscard("You must use 2D length")]] constexpr Type length_2d() const
+        [[nodiscard("You must use 2D length")]] constexpr Type length_2d() const noexcept
         {
             return Vector2<Type>::length();
         }
-        [[nodiscard("You must use distance")]] Type distance_to(const Vector3& other) const
+        [[nodiscard("You must use distance")]] OMATH_CONSTEXPR Type distance_to(const Vector3& other) const noexcept
         {
             return (*this - other).length();
         }
-        [[nodiscard("You must use normalized vector")]] constexpr Vector3 normalized() const
+        [[nodiscard("You must use normalized vector")]] constexpr Vector3 normalized() const noexcept
         {
             const Type length_value = this->length();
 
@@ -161,13 +165,17 @@ namespace omath
         }
 #else
         [[nodiscard("You must use length")]]
-        Type length() const noexcept
+        OMATH_CONSTEXPR Type length() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::sqrt(this->x * this->x + this->y * this->y + this->z * this->z);
+#else
             return std::hypot(this->x, this->y, z);
+#endif
         }
 
         [[nodiscard("You must use normalized vector")]]
-        Vector3 normalized() const noexcept
+        OMATH_CONSTEXPR Vector3 normalized() const noexcept
         {
             const Type len = this->length();
 
@@ -175,13 +183,13 @@ namespace omath
         }
 
         [[nodiscard("You must use 2D length")]]
-        Type length_2d() const noexcept
+        OMATH_CONSTEXPR Type length_2d() const noexcept
         {
             return Vector2<Type>::length();
         }
 
         [[nodiscard("You must use distance")]]
-        Type distance_to(const Vector3& v_other) const noexcept
+        OMATH_CONSTEXPR Type distance_to(const Vector3& v_other) const noexcept
         {
             return (*this - v_other).length();
         }
@@ -249,24 +257,28 @@ namespace omath
         }
 
         [[nodiscard("You must use direction check result")]]
-        bool point_to_same_direction(const Vector3& other) const
+        OMATH_CONSTEXPR bool point_to_same_direction(const Vector3& other) const
         {
             return dot(other) > static_cast<Type>(0);
         }
         [[nodiscard("You must use angle between vectors")]]
-        std::expected<Angle<float, 0.f, 180.f, AngleFlags::Clamped>, Vector3Error>
+        OMATH_CONSTEXPR std::expected<Angle<float, 0.f, 180.f, AngleFlags::Clamped>, Vector3Error>
         angle_between(const Vector3& other) const noexcept
         {
             const auto bottom = length() * other.length();
 
             if (bottom == static_cast<Type>(0))
                 return std::unexpected(Vector3Error::IMPOSSIBLE_BETWEEN_ANGLE);
-
+#ifdef OMATH_USE_GCEM
+            return Angle<float, 0.f, 180.f, AngleFlags::Clamped>::from_radians(gcem::acos(dot(other) / bottom));
+#else
             return Angle<float, 0.f, 180.f, AngleFlags::Clamped>::from_radians(std::acos(dot(other) / bottom));
+#endif
         }
 
         [[nodiscard("You must use perpendicularity check result")]]
-        bool is_perpendicular(const Vector3& other, Type epsilon = static_cast<Type>(0.0001)) const noexcept
+        OMATH_CONSTEXPR bool is_perpendicular(const Vector3& other,
+                                              Type epsilon = static_cast<Type>(0.0001)) const noexcept
         {
             if (const auto angle = angle_between(other))
                 return std::abs(angle->as_degrees() - static_cast<Type>(90)) <= epsilon;
@@ -287,25 +299,25 @@ namespace omath
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator<(const Vector3& other) const noexcept
+        OMATH_CONSTEXPR bool operator<(const Vector3& other) const noexcept
         {
             return length() < other.length();
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator>(const Vector3& other) const noexcept
+        OMATH_CONSTEXPR bool operator>(const Vector3& other) const noexcept
         {
             return length() > other.length();
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator<=(const Vector3& other) const noexcept
+        OMATH_CONSTEXPR bool operator<=(const Vector3& other) const noexcept
         {
             return length() <= other.length();
         }
 
         [[nodiscard("You must use comparison result")]]
-        bool operator>=(const Vector3& other) const noexcept
+        OMATH_CONSTEXPR bool operator>=(const Vector3& other) const noexcept
         {
             return length() >= other.length();
         }
@@ -320,6 +332,7 @@ namespace omath
 
 template<> struct std::hash<omath::Vector3<float>>
 {
+    // NOTE: Cannot be constexpr because of MSVC
     [[nodiscard("You must use hash value")]]
     std::size_t operator()(const omath::Vector3<float>& vec) const noexcept
     {

include/omath/trigonometry/angle.hpp

@@ -3,6 +3,7 @@
 //
 
 #pragma once
+#include "omath/internal/optional_constexpr_math.hpp"
 #include "omath/trigonometry/angles.hpp"
 #include <algorithm>
 #include <format>
@@ -70,31 +71,51 @@ namespace omath
         }
 
         [[nodiscard]]
-        Type sin() const noexcept
+        OMATH_CONSTEXPR Type sin() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::sin(as_radians());
+#else
             return std::sin(as_radians());
+
+#endif
         }
 
         [[nodiscard]]
-        Type cos() const noexcept
+        OMATH_CONSTEXPR Type cos() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::cos(as_radians());
+#else
             return std::cos(as_radians());
+
+#endif
         }
 
         [[nodiscard]]
-        Type tan() const noexcept
+        OMATH_CONSTEXPR Type tan() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::tan(as_radians());
+#else
             return std::tan(as_radians());
+
+#endif
         }
 
         [[nodiscard]]
-        Type atan() const noexcept
+        OMATH_CONSTEXPR Type atan() const noexcept
         {
+#ifdef OMATH_USE_GCEM
+            return gcem::atan(as_radians());
+#else
             return std::atan(as_radians());
+
+#endif
         }
 
         [[nodiscard]]
-        Type cot() const noexcept
+        OMATH_CONSTEXPR Type cot() const noexcept
         {
             return cos() / sin();
         }

include/omath/trigonometry/angles.hpp

@@ -3,6 +3,7 @@
 //
 
 #pragma once
+#include "omath/internal/optional_constexpr_math.hpp"
 #include <cmath>
 #include <numbers>
 
@@ -47,14 +48,18 @@ namespace omath::angles
 
     template<class Type>
     requires std::is_arithmetic_v<Type>
-    [[nodiscard]] Type wrap_angle(const Type& angle, const Type& min, const Type& max) noexcept
+    [[nodiscard]] OMATH_CONSTEXPR Type wrap_angle(const Type& angle, const Type& min, const Type& max) noexcept
     {
         if (angle <= max && angle >= min)
             return angle;
 
         const Type range = max - min;
 
+#ifdef OMATH_USE_GCEM
+        Type wrapped_angle = gcem::fmod(angle - min, range);
+#else
         Type wrapped_angle = std::fmod(angle - min, range);
+#endif
 
         if (wrapped_angle < 0)
             wrapped_angle += range;

source/engines/cry_engine/formulas.cpp

@@ -1,70 +0,0 @@
-//
-// Created by Vlad on 3/22/2025.
-//
-#include "omath/engines/cry_engine/formulas.hpp"
-
-namespace omath::cry_engine
-{
-    Vector3<float> forward_vector(const ViewAngles& angles) noexcept
-    {
-        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_forward);
-
-        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
-    }
-    Vector3<float> right_vector(const ViewAngles& angles) noexcept
-    {
-        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_right);
-
-        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
-    }
-    Vector3<float> up_vector(const ViewAngles& angles) noexcept
-    {
-        const auto vec = rotation_matrix(angles) * mat_column_from_vector(k_abs_up);
-
-        return {vec.at(0, 0), vec.at(1, 0), vec.at(2, 0)};
-    }
-    Mat4X4 calc_view_matrix(const ViewAngles& angles, const Vector3<float>& cam_origin) noexcept
-    {
-        return mat_camera_view<float, MatStoreType::ROW_MAJOR>(forward_vector(angles), right_vector(angles),
-                                                               up_vector(angles), cam_origin);
-    }
-    Mat4X4 rotation_matrix(const ViewAngles& angles) noexcept
-    {
-        return mat_rotation_axis_z<float, MatStoreType::ROW_MAJOR>(angles.yaw)
-               * mat_rotation_axis_y<float, MatStoreType::ROW_MAJOR>(angles.roll)
-               * mat_rotation_axis_x<float, MatStoreType::ROW_MAJOR>(angles.pitch);
-    }
-
-    Vector3<float> extract_origin(const Mat4X4& mat) noexcept
-    {
-        return mat_extract_origin(mat);
-    }
-
-    Vector3<float> extract_scale(const Mat4X4& mat) noexcept
-    {
-        return mat_extract_scale(mat);
-    }
-
-    ViewAngles extract_rotation_angles(const Mat4X4& mat) noexcept
-    {
-        const auto angles = mat_extract_rotation_zyx(mat);
-        return {
-                PitchAngle::from_degrees(angles.x),
-                YawAngle::from_degrees(angles.z),
-                RollAngle::from_degrees(angles.y),
-        };
-    }
-
-    Mat4X4 calc_perspective_projection_matrix(const float field_of_view, const float aspect_ratio, const float near,
-                                              const float far, const NDCDepthRange ndc_depth_range) noexcept
-    {
-        if (ndc_depth_range == NDCDepthRange::ZERO_TO_ONE)
-            return mat_perspective_left_handed_vertical_fov<float, MatStoreType::ROW_MAJOR, NDCDepthRange::ZERO_TO_ONE>(
-                    field_of_view, aspect_ratio, near, far);
-
-        if (ndc_depth_range == NDCDepthRange::NEGATIVE_ONE_TO_ONE)
-            return mat_perspective_left_handed_vertical_fov<float, MatStoreType::ROW_MAJOR, NDCDepthRange::NEGATIVE_ONE_TO_ONE>(
-                    field_of_view, aspect_ratio, near, far);
-        std::unreachable();
-    }
-} // namespace omath::cry_engine

source/engines/cry_engine/traits/camera_trait.cpp

@@ -1,27 +0,0 @@
-//
-// Created by Vlad on 8/11/2025.
-//
-#include "omath/engines/cry_engine/traits/camera_trait.hpp"
-
-namespace omath::cry_engine
-{
-
-    ViewAngles CameraTrait::calc_look_at_angle(const Vector3<float>& cam_origin, const Vector3<float>& look_at) noexcept
-    {
-        const auto direction = (look_at - cam_origin).normalized();
-
-        return {PitchAngle::from_radians(std::asin(direction.z)),
-                YawAngle::from_radians(-std::atan2(direction.x, direction.y)), RollAngle::from_radians(0.f)};
-    }
-    Mat4X4 CameraTrait::calc_view_matrix(const ViewAngles& angles, const Vector3<float>& cam_origin) noexcept
-    {
-        return cry_engine::calc_view_matrix(angles, cam_origin);
-    }
-    Mat4X4 CameraTrait::calc_projection_matrix(const projection::FieldOfView& fov,
-                                               const projection::ViewPort& view_port, const float near,
-                                               const float far, const NDCDepthRange ndc_depth_range) noexcept
-    {
-        return calc_perspective_projection_matrix(fov.as_degrees(), view_port.aspect_ratio(), near, far,
-                                                  ndc_depth_range);
-    }
-} // namespace omath::cry_engine

source/utility/pe_pattern_scan.cpp

@@ -474,7 +474,7 @@ namespace omath
                     {
                         const auto* section = section_table + i;
 
-                        if (std::string_view{section->name, sizeof(section->name)} != target_section_name
+                        if (std::string_view{section->name} != target_section_name
                             || section->size_raw_data == 0)
                             continue;
 

tests/engines/unit_test_cry_engine.cpp

@@ -9,6 +9,98 @@
 #include <ranges>
 
 using namespace omath;
+
+#ifdef OMATH_USE_GCEM
+namespace
+{
+    constexpr bool close_to(const float actual, const float expected, const float epsilon)
+    {
+        const float diff = actual - expected;
+        return (diff < 0.0f ? -diff : diff) <= epsilon;
+    }
+
+    constexpr bool vec_close_to(const Vector3<float>& actual, const Vector3<float>& expected, const float epsilon)
+    {
+        return close_to(actual.x, expected.x, epsilon) && close_to(actual.y, expected.y, epsilon)
+               && close_to(actual.z, expected.z, epsilon);
+    }
+} // namespace
+
+static_assert(
+        []
+        {
+            constexpr omath::cry_engine::ViewAngles angles{};
+            constexpr auto forward = omath::cry_engine::forward_vector(angles);
+            constexpr auto right = omath::cry_engine::right_vector(angles);
+            constexpr auto up = omath::cry_engine::up_vector(angles);
+            constexpr auto rotation = omath::cry_engine::rotation_matrix(angles);
+
+            return vec_close_to(forward, omath::cry_engine::k_abs_forward, 1e-5f)
+                   && vec_close_to(right, omath::cry_engine::k_abs_right, 1e-5f)
+                   && vec_close_to(up, omath::cry_engine::k_abs_up, 1e-5f) && close_to(rotation.at(0, 0), 1.0f, 1e-5f)
+                   && close_to(rotation.at(1, 1), 1.0f, 1e-5f) && close_to(rotation.at(2, 2), 1.0f, 1e-5f)
+                   && close_to(rotation.at(3, 3), 1.0f, 1e-5f);
+        }(),
+        "CryEngine basis vectors should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto view = omath::cry_engine::calc_view_matrix({}, {});
+            return close_to(view.at(0, 0), 1.0f, 1e-5f) && close_to(view.at(1, 2), 1.0f, 1e-5f)
+                   && close_to(view.at(2, 1), 1.0f, 1e-5f) && close_to(view.at(3, 3), 1.0f, 1e-5f);
+        }(),
+        "CryEngine view matrix should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto transform = mat_translation<float, MatStoreType::ROW_MAJOR>({1.0f, 2.0f, 3.0f})
+                                       * mat_scale<float, MatStoreType::ROW_MAJOR>({2.0f, 3.0f, 4.0f});
+            constexpr auto origin = omath::cry_engine::extract_origin(transform);
+            constexpr auto scale = omath::cry_engine::extract_scale(transform);
+
+            return vec_close_to(origin, {1.0f, 2.0f, 3.0f}, 1e-5f) && vec_close_to(scale, {2.0f, 3.0f, 4.0f}, 1e-5f);
+        }(),
+        "CryEngine transform extraction should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto projection = omath::cry_engine::calc_perspective_projection_matrix(
+                    90.0f, 1.0f, 1.0f, 11.0f, NDCDepthRange::ZERO_TO_ONE);
+            return close_to(projection.at(0, 0), 1.0f, 1e-5f) && close_to(projection.at(1, 1), 1.0f, 1e-5f)
+                   && close_to(projection.at(2, 2), 1.1f, 1e-5f) && close_to(projection.at(2, 3), -1.1f, 1e-5f)
+                   && close_to(projection.at(3, 2), 1.0f, 1e-5f);
+        }(),
+        "CryEngine projection matrix should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto angles =
+                    omath::cry_engine::CameraTrait::calc_look_at_angle({}, omath::cry_engine::k_abs_forward);
+            constexpr auto view = omath::cry_engine::CameraTrait::calc_view_matrix(angles, {});
+            constexpr auto projection = omath::cry_engine::CameraTrait::calc_projection_matrix(
+                    projection::FieldOfView::from_degrees(90.0f), {1.0f, 1.0f}, 1.0f, 11.0f,
+                    NDCDepthRange::ZERO_TO_ONE);
+
+            return close_to(angles.pitch.as_degrees(), 0.0f, 1e-5f) && close_to(angles.yaw.as_degrees(), 0.0f, 1e-5f)
+                   && close_to(angles.roll.as_degrees(), 0.0f, 1e-5f) && close_to(view.at(0, 0), 1.0f, 1e-5f)
+                   && close_to(view.at(2, 1), 1.0f, 1e-5f) && close_to(projection.at(0, 0), 1.0f, 1e-5f)
+                   && close_to(projection.at(1, 1), 1.0f, 1e-5f) && close_to(projection.at(2, 2), 1.1f, 1e-5f)
+                   && close_to(projection.at(2, 3), -1.1f, 1e-5f) && close_to(projection.at(3, 2), 1.0f, 1e-5f);
+        }(),
+        "CryEngine CameraTrait should be constexpr with gcem");
+
+static_assert(omath::cry_engine::units_to_centimeters(100.0f) == 1.0f);
+static_assert(omath::cry_engine::units_to_meters(2.0f) == 2.0f);
+static_assert(omath::cry_engine::units_to_kilometers(2000.0f) == 2.0f);
+static_assert(omath::cry_engine::centimeters_to_units(1.0f) == 100.0f);
+static_assert(omath::cry_engine::meters_to_units(2.0f) == 2.0f);
+static_assert(omath::cry_engine::kilometers_to_units(2.0f) == 2000.0f);
+#endif
+
 TEST(unit_test_cry_engine, look_at_forward)
 {
     const auto angles = cry_engine::CameraTrait::calc_look_at_angle({}, cry_engine::k_abs_forward);
@@ -251,11 +343,9 @@ TEST(unit_test_cry_engine, ViewAnglesAsVector3Zero)
 
 TEST(unit_test_cry_engine, ViewAnglesAsVector3Values)
 {
-    const omath::cry_engine::ViewAngles angles{
+    const omath::cry_engine::ViewAngles angles{omath::cry_engine::PitchAngle::from_degrees(45.f),
-        omath::cry_engine::PitchAngle::from_degrees(45.f),
+                                               omath::cry_engine::YawAngle::from_degrees(-90.f),
-        omath::cry_engine::YawAngle::from_degrees(-90.f),
+                                               omath::cry_engine::RollAngle::from_degrees(30.f)};
-        omath::cry_engine::RollAngle::from_degrees(30.f)
-    };
     const auto vec = angles.as_vector3();
 
     EXPECT_FLOAT_EQ(vec.x, 45.f);
@@ -266,11 +356,9 @@ TEST(unit_test_cry_engine, ViewAnglesAsVector3Values)
 TEST(unit_test_cry_engine, ViewAnglesAsVector3ClampedPitch)
 {
     // Pitch is clamped to [-90, 90]
-    const omath::cry_engine::ViewAngles angles{
+    const omath::cry_engine::ViewAngles angles{omath::cry_engine::PitchAngle::from_degrees(120.f),
-        omath::cry_engine::PitchAngle::from_degrees(120.f),
+                                               omath::cry_engine::YawAngle::from_degrees(0.f),
-        omath::cry_engine::YawAngle::from_degrees(0.f),
+                                               omath::cry_engine::RollAngle::from_degrees(0.f)};
-        omath::cry_engine::RollAngle::from_degrees(0.f)
-    };
     const auto vec = angles.as_vector3();
 
     EXPECT_FLOAT_EQ(vec.x, 90.f);
@@ -279,12 +367,10 @@ TEST(unit_test_cry_engine, ViewAnglesAsVector3ClampedPitch)
 TEST(unit_test_cry_engine, ViewAnglesAsVector3NormalizedYaw)
 {
     // Yaw is normalized to [-180, 180], 270 wraps to -90
-    const omath::cry_engine::ViewAngles angles{
+    const omath::cry_engine::ViewAngles angles{omath::cry_engine::PitchAngle::from_degrees(0.f),
-        omath::cry_engine::PitchAngle::from_degrees(0.f),
+                                               omath::cry_engine::YawAngle::from_degrees(270.f),
-        omath::cry_engine::YawAngle::from_degrees(270.f),
+                                               omath::cry_engine::RollAngle::from_degrees(0.f)};
-        omath::cry_engine::RollAngle::from_degrees(0.f)
-    };
     const auto vec = angles.as_vector3();
 
     EXPECT_NEAR(vec.y, -90.f, 0.01f);
-}
+}

tests/general/unit_test_angle.cpp

@@ -2,10 +2,10 @@
 // Created by Orange on 11/30/2024.
 //
 
-#include <omath/trigonometry/angle.hpp>
 #include <cmath>
 #include <gtest/gtest.h>
 #include <numbers>
+#include <omath/trigonometry/angle.hpp>
 
 using namespace omath;
 
@@ -19,6 +19,14 @@ namespace
 
     constexpr float k_eps = 1e-5f;
 
+#ifdef OMATH_USE_GCEM
+    constexpr bool close_to(const float actual, const float expected, const float epsilon)
+    {
+        const float diff = actual - expected;
+        return (diff < 0.0f ? -diff : diff) <= epsilon;
+    }
+#endif
+
 } // namespace
 
 // ---------- Construction / factories ----------
@@ -190,3 +198,11 @@ TEST(UnitTestAngle, BinaryMinus_ReturnsWrappedDiff)
     const Deg c = a - b; // expect 340°
     EXPECT_FLOAT_EQ(c.as_degrees(), 340.0f);
 }
+
+#ifdef OMATH_USE_GCEM
+static_assert(close_to(Pitch::from_degrees(0.0f).sin(), 0.0f, k_eps), "Sin should be constexpr with gcem");
+static_assert(close_to(Pitch::from_degrees(0.0f).cos(), 1.0f, k_eps), "Cos should be constexpr with gcem");
+static_assert(close_to(Pitch::from_degrees(45.0f).tan(), 1.0f, 1e-4f), "Tan should be constexpr with gcem");
+static_assert(close_to(Pitch::from_degrees(45.0f).cot(), 1.0f, 1e-4f), "Cot should be constexpr with gcem");
+static_assert(close_to(Pitch::from_degrees(45.0f).atan(), 0.66577375f, 1e-6f), "Atan should be constexpr with gcem");
+#endif

tests/general/unit_test_mat.cpp

@@ -1,11 +1,25 @@
 // UnitTestMat.cpp
 #include "omath/linear_algebra/mat.hpp"
 #include "omath/linear_algebra/vector3.hpp"
+#include "omath/trigonometry/angle.hpp"
 #include "omath/trigonometry/angles.hpp"
 #include <gtest/gtest.h>
 
 using namespace omath;
 
+#ifdef OMATH_USE_GCEM
+namespace
+{
+    using Pitch = Angle<float, static_cast<float>(-90), static_cast<float>(90), AngleFlags::Clamped>;
+
+    constexpr bool close_to(const float actual, const float expected, const float epsilon)
+    {
+        const float diff = actual - expected;
+        return (diff < 0.0f ? -diff : diff) <= epsilon;
+    }
+} // namespace
+#endif
+
 class UnitTestMat : public ::testing::Test
 {
 protected:
@@ -522,4 +536,48 @@ TEST(UnitTestMatStandalone, MatOrthoNegativeOneToOneDefault)
             NDCDepthRange::NEGATIVE_ONE_TO_ONE>(-1.f, 1.f, -1.f, 1.f, 0.1f, 100.f);
 
     EXPECT_EQ(ortho_default, ortho_explicit);
-}
+}
+
+#ifdef OMATH_USE_GCEM
+static_assert(
+        []
+        {
+            constexpr auto scale = mat_extract_scale(mat_scale(Vector3{2.0f, 3.0f, 4.0f}));
+            return close_to(scale.x, 2.0f, 1e-5f) && close_to(scale.y, 3.0f, 1e-5f) && close_to(scale.z, 4.0f, 1e-5f);
+        }(),
+        "Mat scale extraction should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto rotation = mat_rotation_axis_z<float>(Pitch::from_degrees(90.0f));
+            return close_to(rotation.at(0, 0), 0.0f, 1e-5f) && close_to(rotation.at(0, 1), -1.0f, 1e-5f)
+                   && close_to(rotation.at(1, 0), 1.0f, 1e-5f) && close_to(rotation.at(1, 1), 0.0f, 1e-5f)
+                   && close_to(rotation.at(2, 2), 1.0f, 1e-5f) && close_to(rotation.at(3, 3), 1.0f, 1e-5f);
+        }(),
+        "Mat rotation should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto projection =
+                    mat_perspective_left_handed_vertical_fov<float, MatStoreType::ROW_MAJOR,
+                                                             NDCDepthRange::ZERO_TO_ONE>(90.0f, 1.0f, 1.0f, 11.0f);
+            return close_to(projection.at(0, 0), 1.0f, 1e-5f) && close_to(projection.at(1, 1), 1.0f, 1e-5f)
+                   && close_to(projection.at(2, 2), 1.1f, 1e-5f) && close_to(projection.at(2, 3), -1.1f, 1e-5f)
+                   && close_to(projection.at(3, 2), 1.0f, 1e-5f);
+        }(),
+        "Mat vertical-FOV perspective should be constexpr with gcem");
+
+static_assert(
+        []
+        {
+            constexpr auto projection =
+                    mat_perspective_right_handed_horizontal_fov<float, MatStoreType::ROW_MAJOR,
+                                                                NDCDepthRange::ZERO_TO_ONE>(90.0f, 2.0f, 1.0f, 11.0f);
+            return close_to(projection.at(0, 0), 1.0f, 1e-5f) && close_to(projection.at(1, 1), 2.0f, 1e-5f)
+                   && close_to(projection.at(2, 2), -1.1f, 1e-5f) && close_to(projection.at(2, 3), -1.1f, 1e-5f)
+                   && close_to(projection.at(3, 2), -1.0f, 1e-5f);
+        }(),
+        "Mat horizontal-FOV perspective should be constexpr with gcem");
+#endif

tests/general/unit_test_triangle.cpp

@@ -8,6 +8,17 @@
 
 using namespace omath;
 
+#ifdef OMATH_USE_GCEM
+namespace
+{
+    constexpr bool close_to(const float actual, const float expected, const float epsilon)
+    {
+        const float diff = actual - expected;
+        return (diff < 0.0f ? -diff : diff) <= epsilon;
+    }
+} // namespace
+#endif
+
 class UnitTestTriangle : public ::testing::Test
 {
 protected:
@@ -129,3 +140,20 @@ TEST_F(UnitTestTriangle, MidPoint)
     EXPECT_FLOAT_EQ(mid2.y, (2.0f + 5.0f + 8.0f) / 3.0f);
     EXPECT_FLOAT_EQ(mid2.z, (3.0f + 6.0f + 9.0f) / 3.0f);
 }
+
+#ifdef OMATH_USE_GCEM
+static_assert(
+        []
+        {
+            constexpr Triangle<Vector3<float>> triangle{{3.0f, 0.0f, 0.0f}, {0.0f, 0.0f, 0.0f}, {0.0f, 4.0f, 0.0f}};
+            constexpr auto normal = triangle.calculate_normal();
+            constexpr auto mid_point = triangle.mid_point();
+
+            return close_to(triangle.side_a_length(), 3.0f, 1e-5f) && close_to(triangle.side_b_length(), 4.0f, 1e-5f)
+                   && close_to(triangle.hypot(), 5.0f, 1e-5f) && triangle.is_rectangular()
+                   && close_to(normal.length(), 1.0f, 1e-5f) && close_to(normal.z, -1.0f, 1e-5f)
+                   && close_to(mid_point.x, 1.0f, 1e-5f) && close_to(mid_point.y, 4.0f / 3.0f, 1e-5f)
+                   && close_to(mid_point.z, 0.0f, 1e-5f);
+        }(),
+        "Triangle helpers should be constexpr with gcem");
+#endif

tests/general/unit_test_vector2.cpp

@@ -2,10 +2,10 @@
 // Created by Vlad on 02.09.2024.
 //
 
-#include <omath/linear_algebra/vector2.hpp>
 #include <cfloat> // For FLT_MAX and FLT_MIN
 #include <cmath> // For std::isinf and std::isnan
 #include <gtest/gtest.h>
+#include <omath/linear_algebra/vector2.hpp>
 
 using namespace omath;
 
@@ -399,7 +399,6 @@ TEST_F(UnitTestVector2, GreaterEqualOperator)
     EXPECT_TRUE(omath::Vector2(1.f, 1.f) >= omath::Vector2<float>{});
 }
 
-
 // ── Cast operator tests ──────────────────────────────────────────────────────
 
 TEST(Vector2Cast, FloatToDouble)
@@ -463,3 +462,9 @@ static_assert(Vector2(1.0f, 2.0f).length_sqr() == 5.0f, "LengthSqr should be 5")
 static_assert(Vector2(1.0f, 2.0f).dot(Vector2(4.0f, 5.0f)) == 14.0f, "Dot product should be 14");
 static_assert(Vector2(4.0f, 5.0f).distance_to_sqr(Vector2(1.0f, 2.0f)) == 18.0f, "DistToSqr should be 18");
 static_assert(Vector2(-1.0f, -2.0f).abs() == Vector2(1.0f, 2.0f), "Abs should convert negative values to positive");
+
+#ifdef OMATH_USE_GCEM
+static_assert(Vector2(3.0f, 4.0f).length() == 5.0f, "Length should be constexpr with gcem");
+static_assert(Vector2(0.0f, 0.0f).distance_to(Vector2(3.0f, 4.0f)) == 5.0f, "Distance should be constexpr with gcem");
+static_assert(Vector2(1.0f, 1.0f) < Vector2(3.0f, 4.0f), "Comparison should be constexpr with gcem");
+#endif

tests/general/unit_test_vector3.cpp

@@ -2,11 +2,11 @@
 // Created by Vlad on 01.09.2024.
 //
 
-#include <omath/linear_algebra/vector3.hpp>
 #include <cfloat> // For FLT_MAX, FLT_MIN
 #include <cmath>
 #include <gtest/gtest.h>
 #include <limits> // For std::numeric_limits
+#include <omath/linear_algebra/vector3.hpp>
 
 using namespace omath;
 
@@ -31,35 +31,33 @@ TEST(Vector3More, ArithmeticAndDotCross)
     constexpr Vector3<float> a{1.f, 0.f, 0.f};
     constexpr Vector3<float> b{0.f, 1.f, 0.f};
     const auto c = a + b;
-    constexpr Vector3<float> expect_c{1.f,1.f,0.f};
+    constexpr Vector3<float> expect_c{1.f, 1.f, 0.f};
     EXPECT_EQ(c, expect_c);
 
     const auto d = a - b;
-    constexpr Vector3<float> expect_d{1.f,-1.f,0.f};
+    constexpr Vector3<float> expect_d{1.f, -1.f, 0.f};
     EXPECT_EQ(d, expect_d);
 
     const auto e = a * 2.f;
-    constexpr Vector3<float> expect_e{2.f,0.f,0.f};
+    constexpr Vector3<float> expect_e{2.f, 0.f, 0.f};
     EXPECT_EQ(e, expect_e);
 
     EXPECT_FLOAT_EQ(a.dot(b), 0.f);
     // manual cross product check
-    const auto cr = Vector3<float>{ a.y * b.z - a.z * b.y,
+    const auto cr = Vector3<float>{a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x};
-                              a.z * b.x - a.x * b.z,
+    constexpr Vector3<float> expect_cr{0.f, 0.f, 1.f};
-                              a.x * b.y - a.y * b.x };
-    constexpr Vector3<float> expect_cr{0.f,0.f,1.f};
     EXPECT_EQ(cr, expect_cr);
 }
 
 TEST(Vector3More, NormalizationEdgeCases)
 {
-    constexpr Vector3<double> z{0.0,0.0,0.0};
+    constexpr Vector3<double> z{0.0, 0.0, 0.0};
     const auto zn = z.normalized();
     EXPECT_DOUBLE_EQ(zn.x, 0.0);
     EXPECT_DOUBLE_EQ(zn.y, 0.0);
     EXPECT_DOUBLE_EQ(zn.z, 0.0);
 
-    constexpr Vector3<double> v{3.0,4.0,0.0};
+    constexpr Vector3<double> v{3.0, 4.0, 0.0};
     const auto vn = v.normalized();
     EXPECT_NEAR(vn.x, 0.6, 1e-12);
     EXPECT_NEAR(vn.y, 0.8, 1e-12);
@@ -481,16 +479,14 @@ TEST_F(UnitTestVector3, AsTuple)
 // Test AsTuple method
 TEST_F(UnitTestVector3, AngleBeatween)
 {
-    EXPECT_NEAR(Vector3(0.0f, 0.0f, 1.0f).angle_between({1, 0, 0}).value().as_degrees(),
+    EXPECT_NEAR(Vector3(0.0f, 0.0f, 1.0f).angle_between({1, 0, 0}).value().as_degrees(), 90.0f, 0.001f);
-                90.0f, 0.001f);
+    EXPECT_NEAR(Vector3(0.0f, 0.0f, 1.0f).angle_between({0.0f, 0.0f, 1.0f}).value().as_degrees(), 0.0f, 0.001f);
-    EXPECT_NEAR(Vector3(0.0f, 0.0f, 1.0f).angle_between({0.0f, 0.0f, 1.0f}).value().as_degrees(),
-                0.0f, 0.001f);
     EXPECT_FALSE(Vector3(0.0f, 0.0f, 0.0f).angle_between({0.0f, 0.0f, 1.0f}).has_value());
 }
 
 TEST_F(UnitTestVector3, IsPerpendicular)
 {
-    EXPECT_EQ(Vector3(0.0f, 0.0f, 1.0f).is_perpendicular({1, 0 ,0}), true);
+    EXPECT_EQ(Vector3(0.0f, 0.0f, 1.0f).is_perpendicular({1, 0, 0}), true);
     EXPECT_EQ(Vector3(0.0f, 0.0f, 1.0f).is_perpendicular({0.0f, 0.0f, 1.0f}), false);
     EXPECT_FALSE(Vector3(0.0f, 0.0f, 0.0f).is_perpendicular({0.0f, 0.0f, 1.0f}));
 }
@@ -585,4 +581,19 @@ TEST(Vector3Cast, SameTypeRoundtrip)
 static_assert(Vector3(1.0f, 2.0f, 3.0f).length_sqr() == 14.0f, "LengthSqr should be 14");
 static_assert(Vector3(1.0f, 2.0f, 3.0f).dot(Vector3(4.0f, 5.0f, 6.0f)) == 32.0f, "Dot product should be 32");
 static_assert(Vector3(4.0f, 5.0f, 6.0f).distance_to_sqr(Vector3(1.0f, 2.0f, 3.0f)) == 27.0f, "DistToSqr should be 27");
-static_assert(Vector3(-1.0f, -2.0f, -3.0f).abs() == Vector3(1.0f, 2.0f, 3.0f), "Abs should convert negative values to positive");
+static_assert(Vector3(-1.0f, -2.0f, -3.0f).abs() == Vector3(1.0f, 2.0f, 3.0f),
+              "Abs should convert negative values to positive");
+
+#ifdef OMATH_USE_GCEM
+static_assert(Vector3(1.0f, 2.0f, 2.0f).length() == 3.0f, "Length should be constexpr with gcem");
+static_assert(Vector3(0.0f, 0.0f, 0.0f).distance_to(Vector3(1.0f, 2.0f, 2.0f)) == 3.0f,
+              "Distance should be constexpr with gcem");
+static_assert(Vector3(1.0f, 1.0f, 1.0f) < Vector3(3.0f, 4.0f, 5.0f), "Comparison should be constexpr with gcem");
+static_assert(
+        []
+        {
+            constexpr auto angle = Vector3(1.0f, 0.0f, 0.0f).angle_between(Vector3(0.0f, 1.0f, 0.0f));
+            return angle.has_value() && angle->as_degrees() > 89.999f && angle->as_degrees() < 90.001f;
+        }(),
+        "Angle between should be constexpr with gcem");
+#endif

vcpkg.json

@@ -82,6 +82,13 @@
         "lua",
         "sol2"
       ]
+    },
+    "gcem":
+    {
+      "description": "Improve constexpr compatibility using gcem",
+      "dependencies": [
+        "gcem"
+      ]
     }
   }
 }