added aabb line trace

tests/general/unit_test_line_tracer_aabb.cpp

@@ -0,0 +1,126 @@
+//
+// Created by Vlad on 3/25/2025.
+//
+#include "omath/collision/line_tracer.hpp"
+#include "omath/linear_algebra/aabb.hpp"
+#include "omath/linear_algebra/vector3.hpp"
+#include <gtest/gtest.h>
+
+using Vec3 = omath::Vector3<float>;
+using Ray = omath::collision::Ray<>;
+using LineTracer = omath::collision::LineTracer<>;
+using AABB = omath::AABB<Vec3>;
+
+static Ray make_ray(Vec3 start, Vec3 end, bool infinite = false)
+{
+    Ray r;
+    r.start = start;
+    r.end = end;
+    r.infinite_length = infinite;
+    return r;
+}
+
+// Ray passing straight through the center along Z axis
+TEST(LineTracerAABBTests, HitCenterAlongZ)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    const auto ray = make_ray({0.f, 0.f, -5.f}, {0.f, 0.f, 5.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    EXPECT_NEAR(hit.z, -1.f, 1e-4f);
+    EXPECT_NEAR(hit.x, 0.f, 1e-4f);
+    EXPECT_NEAR(hit.y, 0.f, 1e-4f);
+}
+
+// Ray passing straight through the center along X axis
+TEST(LineTracerAABBTests, HitCenterAlongX)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    const auto ray = make_ray({-5.f, 0.f, 0.f}, {5.f, 0.f, 0.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    EXPECT_NEAR(hit.x, -1.f, 1e-4f);
+}
+
+// Ray that misses entirely (too far in Y)
+TEST(LineTracerAABBTests, MissReturnsEnd)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    const auto ray = make_ray({0.f, 5.f, -5.f}, {0.f, 5.f, 5.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_EQ(hit, ray.end);
+}
+
+// Ray that stops short before reaching the box
+TEST(LineTracerAABBTests, RayTooShortReturnsEnd)
+{
+    const AABB box{{3.f, -1.f, -1.f}, {5.f, 1.f, 1.f}};
+    const auto ray = make_ray({0.f, 0.f, 0.f}, {2.f, 0.f, 0.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_EQ(hit, ray.end);
+}
+
+// Infinite ray that starts before the box should hit
+TEST(LineTracerAABBTests, InfiniteRayHits)
+{
+    const AABB box{{3.f, -1.f, -1.f}, {5.f, 1.f, 1.f}};
+    const auto ray = make_ray({0.f, 0.f, 0.f}, {2.f, 0.f, 0.f}, true);
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    EXPECT_NEAR(hit.x, 3.f, 1e-4f);
+}
+
+// Ray starting inside the box — t_min=0, so hit point equals ray.start
+TEST(LineTracerAABBTests, RayStartsInsideBox)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    const auto ray = make_ray({0.f, 0.f, 0.f}, {0.f, 0.f, 5.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    // t_min is clamped to 0, so hit == start
+    EXPECT_NEAR(hit.x, 0.f, 1e-4f);
+    EXPECT_NEAR(hit.y, 0.f, 1e-4f);
+    EXPECT_NEAR(hit.z, 0.f, 1e-4f);
+}
+
+// Ray parallel to XY plane, pointing along X, at Z outside the box
+TEST(LineTracerAABBTests, ParallelRayOutsideSlabMisses)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    // Z component of ray is 3.0 — outside box's Z slab
+    const auto ray = make_ray({-5.f, 0.f, 3.f}, {5.f, 0.f, 3.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_EQ(hit, ray.end);
+}
+
+// Ray parallel to XY plane, pointing along X, at Z inside the box
+TEST(LineTracerAABBTests, ParallelRayInsideSlabHits)
+{
+    const AABB box{{-1.f, -1.f, -1.f}, {1.f, 1.f, 1.f}};
+    const auto ray = make_ray({-5.f, 0.f, 0.f}, {5.f, 0.f, 0.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    EXPECT_NEAR(hit.x, -1.f, 1e-4f);
+}
+
+// Diagonal ray hitting a corner region
+TEST(LineTracerAABBTests, DiagonalRayHits)
+{
+    const AABB box{{0.f, 0.f, 0.f}, {2.f, 2.f, 2.f}};
+    const auto ray = make_ray({-1.f, -1.f, -1.f}, {3.f, 3.f, 3.f});
+
+    const auto hit = LineTracer::get_ray_hit_point(ray, box);
+    EXPECT_NE(hit, ray.end);
+    // Entry point should be at (0,0,0)
+    EXPECT_NEAR(hit.x, 0.f, 1e-4f);
+    EXPECT_NEAR(hit.y, 0.f, 1e-4f);
+    EXPECT_NEAR(hit.z, 0.f, 1e-4f);
+}