Temp (#123)

* Coverage

* added fixes

* removed spacing

* removed junk

* removed print

* removed coverage

* removed useless stuff

* fix

---------

Co-authored-by: Saikari <lin@sz.cn.eu.org>

tests/general/unit_test_linear_algebra_instantiate.cpp

@@ -0,0 +1,74 @@
+// Instantiation-only tests to force out-of-line template emission
+#include <gtest/gtest.h>
+#include <format>
+#include <functional>
+
+#include "omath/linear_algebra/vector3.hpp"
+#include "omath/linear_algebra/vector4.hpp"
+#include "omath/linear_algebra/mat.hpp"
+
+using namespace omath;
+
+TEST(LinearAlgebraInstantiate, Vector3AndVector4AndMatCoverage) {
+    // Vector3 usage
+    Vector3<float> a{1.f, 2.f, 3.f};
+    Vector3<float> b{4.f, 5.f, 6.f};
+
+    // call various methods
+    volatile float d0 = a.distance_to_sqr(b);
+    volatile float d1 = a.dot(b);
+    volatile auto c = a.cross(b);
+    auto tup = a.as_tuple();
+    volatile bool dir = a.point_to_same_direction(b);
+
+    // non-inlined helpers
+    volatile float ln = a.length();
+    auto ang = a.angle_between(b);
+    volatile bool perp = a.is_perpendicular(b, 0.1f);
+    volatile auto anorm = a.normalized();
+
+    // formatter and hash instantiations (char only)
+    (void)std::format("{}", a);
+    (void)std::hash<Vector3<float>>{}(a);
+
+    // Vector4 usage
+    Vector4<float> v4{1.f, -2.f, 3.f, -4.f};
+    volatile float v4len = v4.length();
+    volatile float v4sum = v4.sum();
+    v4.clamp(-2.f, 2.f);
+    (void)std::format("{}", v4);
+    (void)std::hash<Vector4<float>>{}(v4);
+
+    // Mat usage: instantiate several sizes and store orders
+    Mat<1,1> m1{{42.f}};
+    volatile float m1det = m1.determinant();
+
+    Mat<2,2> m2{{{1.f,2.f},{3.f,4.f}}};
+    volatile float det2 = m2.determinant();
+    auto tr2 = m2.transposed();
+    auto minor00 = m2.minor(0,0);
+    auto algc = m2.alg_complement(0,1);
+    auto rarr = m2.raw_array();
+    auto inv2 = m2.inverted();
+
+    Mat<3,3> m3{{{1.f,2.f,3.f},{4.f,5.f,6.f},{7.f,8.f,9.f}}};
+    volatile float det3 = m3.determinant();
+    auto strip = m3.strip(0,0);
+    auto min = m3.minor(2,2);
+
+    // to_string/wstring/u8string and to_screen_mat
+    auto s = m2.to_string();
+    auto ws = m2.to_wstring();
+    auto u8s = m2.to_u8string();
+    auto screen = Mat<4,4>::to_screen_mat(800.f, 600.f);
+
+    // call non-inlined mat helpers
+    volatile auto det = m2.determinant();
+    volatile auto inv = m2.inverted();
+    volatile auto trans = m2.transposed();
+    volatile auto raw = m2.raw_array();
+
+    // simple sanity checks (not strict, only to use values)
+    EXPECT_EQ(std::get<0>(tup), 1.f);
+    EXPECT_TRUE(det2 != 0.f || inv2 == std::nullopt);
+}