Added planes!

source/shapes/plane.cpp

@@ -0,0 +1,36 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Plane implementation
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <tuple.h>
+#include <ray.h>
+#include <shape.h>
+#include <plane.h>
+#include <math_helper.h>
+
+Intersect Plane::localIntersect(Ray r)
+{
+    double t;
+    Intersect ret = Intersect();
+
+    if (fabs(r.direction.y) < getEpsilon())
+    {
+        /* With a direction == 0, the ray can't intersect the plane */
+        return ret;
+    }
+
+    t = -r.origin.y / r.direction.y;
+
+    ret.add(Intersection(t, this));
+
+    return ret;
+}
+
+Tuple Plane::localNormalAt(Tuple point)
+{
+    return Vector(0, 1, 0);
+}