+void IntersectionTest::testSimpleRayBoxIntersection() {
+ Ray ray{ { 0, 0, 0 }, { 1, 0, 0 } }; // at origin, pointing right
+ ray.Update();
+ AABB box{ { -1, -1, -1 }, { 1, 1, 1 } }; // 2x2x2 cube centered around origin
+
+ const float delta = std::numeric_limits<float>::epsilon();
+
+ float distance = 0;
+
+ CPPUNIT_ASSERT_MESSAGE(
+ "ray at origin not intersecting box at origin",
+ Intersection(ray, box, distance)
+ );
+
+ // move ray outside the box, but have it still point at it
+ // should be 4 units to the left now
+ ray.orig.x = -5;
+ CPPUNIT_ASSERT_MESSAGE(
+ "ray pointing at box doesn't intersect",
+ Intersection(ray, box, distance)
+ );
+ CPPUNIT_ASSERT_DOUBLES_EQUAL_MESSAGE(
+ "intersection distance way off",
+ 4.0f, distance, delta
+ );
+
+ // move ray to the other side, so it's pointing away now
+ ray.orig.x = 5;
+ CPPUNIT_ASSERT_MESSAGE(
+ "ray pointing away from box still intersects",
+ !Intersection(ray, box, distance)
+ );
+
+ // 45 deg down from 4 units away, so should be about 4 * sqrt(2)
+ ray.orig = { -5.0f, 4.5f, 0.0f };
+ ray.dir = { 0.70710678118654752440f, -0.70710678118654752440f, 0.0f };
+ ray.Update();
+ CPPUNIT_ASSERT_MESSAGE(
+ "ray pointing at box doesn't intersect",
+ Intersection(ray, box, distance)
+ );
+ CPPUNIT_ASSERT_DOUBLES_EQUAL_MESSAGE(
+ "intersection distance way off",
+ 5.65685424949238019520f, distance, delta
+ );
+}
+