add another test

tests/general/unit_test_epa.cpp

@@ -77,4 +77,63 @@ TEST(UnitTestEpa, TestCollisionTrue)
     Mesh b_wrong = b;
     b_wrong.set_origin(b_wrong.get_origin() - resolve);
     EXPECT_TRUE(GJK::is_collide(A, Collider(b_wrong)));
-}
+}
+TEST(UnitTestEpa, TestCollisionTrue2)
+{
+    std::vector<omath::Vector3<float>> vbo = {{-1, -1, -1}, {-1, -1, 1}, {-1, 1, -1}, {-1, 1, 1},
+                                              {1, 1, 1},    {1, 1, -1},  {1, -1, 1},  {1, -1, -1}};
+    std::vector<omath::Vector3<std::size_t>> vao; // not needed
+
+    Mesh a(vbo, vao, {1, 1, 1});
+    Mesh b(vbo, vao, {1, 1, 1});
+
+    // Overlap along +X by 0.5
+    a.set_origin({0, 0, 0});
+    b.set_origin({0.5f, 0, 0});
+
+    Collider A(a), B(b);
+
+    // --- GJK must detect collision and provide simplex ---
+    auto gjk = GJK::is_collide_with_simplex_info(A, B);
+    ASSERT_TRUE(gjk.hit) << "GJK should report collision for overlapping cubes";
+
+    // --- EPA penetration ---
+    EPA::Params params;
+    params.max_iterations = 64;
+    params.tolerance = 1e-4f;
+    auto epa = EPA::solve(A, B, gjk.simplex, params);
+    ASSERT_TRUE(epa.success) << "EPA should converge";
+
+    // Normal is unit-length
+    EXPECT_NEAR(epa.normal.dot(epa.normal), 1.0f, 1e-5f);
+
+    // For centers at 0 and +0.5 and half-extent 1 -> depth ≈ 1.5
+    EXPECT_NEAR(epa.depth, 1.5f, 1e-3f);
+
+    // Axis sanity: mostly X
+    EXPECT_NEAR(std::abs(epa.normal.x), 1.0f, 1e-3f);
+    EXPECT_NEAR(epa.normal.y, 0.0f, 1e-3f);
+    EXPECT_NEAR(epa.normal.z, 0.0f, 1e-3f);
+
+    // Choose a deterministic sign: orient penetration from A toward B
+    const auto centers = b.get_origin() - a.get_origin(); // (0.5, 0, 0)
+    float sign = (epa.normal.dot(centers) >= 0.0f) ? +1.0f : -1.0f;
+
+    constexpr float margin = 1.0f + 1e-3f; // tiny slack to avoid grazing
+    const auto pen = epa.normal * epa.depth * sign;
+
+    // Apply once: B + pen must separate; the opposite must still collide
+    Mesh b_resolved = b;
+    b_resolved.set_origin(b_resolved.get_origin() + pen * margin);
+    EXPECT_FALSE(GJK::is_collide(A, Collider(b_resolved))) << "Applying penetration should separate";
+
+    Mesh b_wrong = b;
+    b_wrong.set_origin(b_wrong.get_origin() - pen * margin);
+    EXPECT_TRUE(GJK::is_collide(A, Collider(b_wrong))) << "Opposite direction should still intersect";
+
+    // Some book-keeping sanity
+    EXPECT_GT(epa.iterations, 0);
+    EXPECT_LT(epa.iterations, params.max_iterations);
+    EXPECT_GE(epa.num_faces, 4);
+    EXPECT_GT(epa.num_vertices, 4);
+}