Added planes!

tests/plane_test.cpp

@@ -0,0 +1,71 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Plane unit tests
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+
+#include <ray.h>
+#include <shape.h>
+#include <plane.h>
+#include <material.h>
+#include <transformation.h>
+#include <gtest/gtest.h>
+
+TEST(PlaneTest, The_normal_of_a_plane_is_constant_everywhere)
+{
+    Plane p = Plane();
+    Tuple n1 = p.normalAt(Point(0, 0, 0));
+    Tuple n2 = p.normalAt(Point(10, 0, -10));
+    Tuple n3 = p.normalAt(Point(-5, 0, 0150));
+
+    ASSERT_EQ(n1, Vector(0, 1, 0));
+    ASSERT_EQ(n2, Vector(0, 1, 0));
+    ASSERT_EQ(n3, Vector(0, 1, 0));
+}
+
+TEST(PlaneTest, Intersect_with_a_ray_parallel_to_the_plane)
+{
+    Plane p = Plane();
+    Ray r = Ray(Point(0, 10, 0), Vector(0, 0, 1));
+
+    Intersect xs = p.intersect(r);
+
+    ASSERT_EQ(xs.count(), 0);
+}
+
+TEST(PlaneTest, Intersect_with_a_coplanar_ray)
+{
+    Plane p = Plane();
+    Ray r = Ray(Point(0, 0, 0), Vector(0, 0, 1));
+
+    Intersect xs = p.intersect(r);
+
+    ASSERT_EQ(xs.count(), 0);
+}
+
+TEST(PlaneTest, A_ray_intersecting_a_plane_from_above)
+{
+    Plane p = Plane();
+    Ray r = Ray(Point(0, 1, 0), Vector(0, -1, 0));
+
+    Intersect xs = p.intersect(r);
+
+    ASSERT_EQ(xs.count(), 1);
+    ASSERT_EQ(xs[0].t, 1);
+    ASSERT_EQ(xs[0].object, &p);
+}
+
+TEST(PlaneTest, A_ray_intersecting_a_plane_from_below)
+{
+    Plane p = Plane();
+    Ray r = Ray(Point(0, -1, 0), Vector(0, 1, 0));
+
+    Intersect xs = p.intersect(r);
+
+    ASSERT_EQ(xs.count(), 1);
+    ASSERT_EQ(xs[0].t, 1);
+    ASSERT_EQ(xs[0].object, &p);
+}