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- /*
- * DoRayMe - a quick and dirty Raytracer
- * Cone implementation
- *
- * Created by Manoël Trapier
- * Copyright (c) 2020 986-Studio.
- *
- */
- #include <tuple.h>
- #include <ray.h>
- #include <shape.h>
- #include <cone.h>
- #include <math_helper.h>
- bool Cone::checkCap(Ray r, double t, double y)
- {
- /* Helping function to reduce duplication.
- * Checks to see if the intersection ot t is within a radius
- * of 1 (the radius of our Cone from the y axis
- */
- double x = r.origin.x + t * r.direction.x;
- double z = r.origin.z + t * r.direction.z;
- return (x * x + z * z) <= fabs(y);
- }
- void Cone::intersectCaps(Ray r, Intersect &xs)
- {
- /* Caps only mattter is the Cone is closed, and might possibly be
- * intersected by the ray
- */
- if ((this->isClosed) && (fabs(r.direction.y) > getEpsilon()))
- {
- double t;
- /* Check for an intersection with the lower end cap by intersecting
- * the ray with the plan at y = this->minCap
- */
- t = (this->minCap - r.origin.y) / r.direction.y;
- if (this->checkCap(r, t, this->minCap))
- {
- xs.add(Intersection(t, this));
- }
- /* Check for an intersection with the upper end cap by intersecting
- * the ray with the plan at y = this->maxCap
- */
- t = (this->maxCap - r.origin.y) / r.direction.y;
- if (this->checkCap(r, t, this->maxCap))
- {
- xs.add(Intersection(t, this));
- }
- }
- }
- Intersect Cone::localIntersect(Ray r)
- {
- Intersect ret;
- double A = pow(r.direction.x, 2) -
- pow(r.direction.y, 2) +
- pow(r.direction.z, 2);
- double B = (2 * r.origin.x * r.direction.x) -
- (2 * r.origin.y * r.direction.y) +
- (2 * r.origin.z * r.direction.z);
- double C = pow(r.origin.x, 2) -
- pow(r.origin.y, 2) +
- pow(r.origin.z, 2);
- if ((fabs(A) <= getEpsilon()) && (fabs(B) >= getEpsilon()))
- {
- double t = -C / (2*B);
- ret.add(Intersection(t, this));
- }
- else if (fabs(A) >= getEpsilon())
- {
- double disc = pow(B, 2) - 4 * A * C;
- if (disc >= 0)
- {
- double t0 = (-B - sqrt(disc)) / (2 * A);
- double t1 = (-B + sqrt(disc)) / (2 * A);
- double y0 = r.origin.y + t0 * r.direction.y;
- if ((this->minCap < y0) && (y0 < this->maxCap))
- {
- ret.add(Intersection(t0, this));
- }
- double y1 = r.origin.y + t1 * r.direction.y;
- if ((this->minCap < y1) && (y1 < this->maxCap))
- {
- ret.add(Intersection(t1, this));
- }
- }
- }
- this->intersectCaps(r, ret);
- return ret;
- }
- Tuple Cone::localNormalAt(Tuple point)
- {
- /* Compute the square of the distance from the Y axis */
- double dist = point.x * point.x + point.z * point.z;
- if ((dist < 1) && (point.y >= (this->maxCap - getEpsilon())))
- {
- return Vector(0, 1, 0);
- }
- if ((dist < 1) && (point.y <= this->minCap + getEpsilon()))
- {
- return Vector(0, -1, 0);
- }
- double y = sqrt(point.x * point.x + point.z * point.z);
- if (point.y > 0)
- {
- y = -y;
- }
- return Vector(point.x, y, point.z);
- }
- BoundingBox Cone::getBounds()
- {
- BoundingBox ret;
- double a = fabs(this->minCap);
- double b = fabs(this->maxCap);
- double limit = (a < b)?a:b;
- ret.min = this->objectToWorld(Point(-limit, this->minCap, -limit));
- ret.max = this->objectToWorld(Point(limit, this->maxCap, limit));
- return ret;
- }
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