/* * DoRayMe - a quick and dirty Raytracer * Sphere implementation * * Created by Manoƫl Trapier * Copyright (c) 2020 986-Studio. * */ #include #include #include #include #include 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(); }