AP_Math: Add unit tests for 3-D lines

libraries/AP_Math/tests/test_3d_lines.cpp

@@ -0,0 +1,46 @@
+#include <AP_gtest.h>
+
+#include <AP_Math/vector2.h>
+#include <AP_Math/vector3.h>
+#include <AP_Math/AP_Math.h>
+
+// check if two vector3f are equal 
+#define EXPECT_VECTOR3F_EQ(v1, v2)              \
+    do {                                        \
+        EXPECT_FLOAT_EQ(v1[0], v2[0]);          \
+        EXPECT_FLOAT_EQ(v1[1], v2[1]);          \
+        EXPECT_FLOAT_EQ(v1[2], v2[2]);          \
+    } while (false);
+
+
+TEST(Lines3dTests, ClosestDistBetweenLinePoint)
+{   
+    // check if the 2-d and 3-d variant of this method is same if the third-dimension is zero
+    float dist_3d = Vector3f::closest_distance_between_line_and_point(Vector3f{0.0f, 1.0f, 0.0f}, Vector3f{0.0f, 10.0f, 0.0f}, Vector3f{6.0f, 5.0f, 0.0f});
+    float dist_2d = Vector2f::closest_distance_between_line_and_point(Vector2f{0.0f, 1.0f}, Vector2f{0.0f, 10.0f}, Vector2f{6.0f, 5.0f});
+    EXPECT_FLOAT_EQ(dist_2d, dist_3d);
+
+    // random point test
+    const Vector3f intersection = Vector3f::point_on_line_closest_to_other_point(Vector3f{}, Vector3f{0.0f, 10.0f, 10.0f}, Vector3f{0.0f, 5.0f, 5.0f});
+    EXPECT_VECTOR3F_EQ((Vector3f{0.0f, 5.0f, 5.0f}), intersection);
+}
+
+TEST(Lines3dTests, SegmentToSegmentDistance)
+{   
+    // random segments test
+    Vector3f intersection;
+    float dist = Vector3f::segment_to_segment_dist(Vector3f{-10.0f,0.0f,0.0f}, Vector3f{10.0f,0.0f,0.0f}, Vector3f{0.0f, -5.0f, 1.0}, Vector3f{0.0f, 5.0f, 1.0f}, intersection);
+    EXPECT_FLOAT_EQ(dist, 1.0f);
+    EXPECT_VECTOR3F_EQ(intersection, (Vector3f{0.0f, 0.0f, 1.0f}));
+
+    // check for intersecting segments. Verify with the 2-d variant
+    dist = Vector3f::segment_to_segment_dist(Vector3f{}, Vector3f{10.0f,10.0f,0.0f}, Vector3f{2.0f, -10.0f, 0.0}, Vector3f{3.0f, 10.0f, 0.0f}, intersection);
+    Vector2f intersection_2d;
+    const bool result = Vector2f::segment_intersection(Vector2f{}, Vector2f{10.0f,10.0}, Vector2f{2.0f, -10.0f}, Vector2f{3.0f, 10.0f}, intersection_2d);
+    EXPECT_EQ(true, result); 
+    EXPECT_FLOAT_EQ(dist, 0.0f);
+    EXPECT_VECTOR3F_EQ(intersection, (Vector3f(intersection_2d.x, intersection_2d.y, 0.0f)));
+}
+
+AP_GTEST_MAIN()
+int hal = 0; //weirdly the build will fail without this