Renaming Object to Shape (part 1)

source/shapes/sphere.cpp

@@ -0,0 +1,50 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Sphere implementation
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <math.h>
+
+#include <sphere.h>
+#include <ray.h>
+#include <tuple.h>
+#include <intersect.h>
+
+Intersect Sphere::intersect(Ray r)
+{
+    Intersect ret;
+    double a, b, c, discriminant;
+
+    Ray transRay = this->invTransform(r);
+
+    Tuple sphere_to_ray = transRay.origin - Point(0, 0, 0);
+
+    a = transRay.direction.dot(transRay.direction);
+    b = 2 * transRay.direction.dot(sphere_to_ray);
+    c = sphere_to_ray.dot(sphere_to_ray) - 1;
+
+    discriminant = b * b - 4 * a * c;
+
+    if (discriminant >= 0)
+    {
+        ret.add(Intersection((-b - sqrt(discriminant)) / (2 * a), this));
+        ret.add(Intersection((-b + sqrt(discriminant)) / (2 * a), this));
+    }
+
+    return ret;
+}
+
+Tuple Sphere::normalAt(Tuple point)
+{
+    Tuple object_point = this->inverseTransform * point;
+    Tuple object_normal = (object_point - Point(0, 0, 0)).normalise();
+    Tuple world_normal = this->inverseTransform.transpose() * object_normal;
+
+    /* W may get wrong, so hack it. This is perfectly normal as we are using a 4x4 matrix instead of a 3x3 */
+    world_normal.w = 0;
+
+    return world_normal.normalise();
+}