128 lines
3.4 KiB
C++
128 lines
3.4 KiB
C++
/*
|
|
* DoRayMe - a quick and dirty Raytracer
|
|
* Cylinder implementation
|
|
*
|
|
* Created by Manoël Trapier
|
|
* Copyright (c) 2020 986-Studio.
|
|
*
|
|
*/
|
|
#include <tuple.h>
|
|
#include <ray.h>
|
|
#include <shape.h>
|
|
#include <cylinder.h>
|
|
#include <math_helper.h>
|
|
|
|
bool Cylinder::checkCap(Ray r, double t)
|
|
{
|
|
/* Helping function to reduce duplication.
|
|
* Checks to see if the intersection ot t is within a radius
|
|
* of 1 (the radius of our cylinder 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) <= 1;
|
|
}
|
|
|
|
void Cylinder::intersectCaps(Ray r, Intersect &xs)
|
|
{
|
|
/* Caps only matter if the cylinder 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))
|
|
{
|
|
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))
|
|
{
|
|
xs.add(Intersection(t, this));
|
|
}
|
|
}
|
|
}
|
|
|
|
void Cylinder::localIntersect(Ray r, Intersect &xs)
|
|
{
|
|
double A = r.direction.x * r.direction.x + r.direction.z * r.direction.z;
|
|
|
|
/* Ray is parallel to the Y axis */
|
|
if (A >= getEpsilon())
|
|
{
|
|
double B = 2 * r.origin.x * r.direction.x +
|
|
2 * r.origin.z * r.direction.z;
|
|
double C = r.origin.x * r.origin.x + r.origin.z * r.origin.z - 1;
|
|
|
|
double disc = B * B - 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))
|
|
{
|
|
xs.add(Intersection(t0, this));
|
|
}
|
|
|
|
double y1 = r.origin.y + t1 * r.direction.y;
|
|
if ((this->minCap < y1) && (y1 < this->maxCap))
|
|
{
|
|
xs.add(Intersection(t1, this));
|
|
}
|
|
}
|
|
}
|
|
|
|
this->intersectCaps(r, xs);
|
|
}
|
|
|
|
Tuple Cylinder::localNormalAt(Tuple point, Intersection *hit)
|
|
{
|
|
/* 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);
|
|
}
|
|
|
|
return Vector(point.x, 0, point.z);
|
|
}
|
|
|
|
BoundingBox Cylinder::getLocalBounds()
|
|
{
|
|
BoundingBox ret;
|
|
|
|
ret | Point(-1, this->minCap, -1);
|
|
ret | Point(1, this->maxCap, 1);
|
|
|
|
return ret;
|
|
}
|
|
|
|
void Cylinder::dumpMe(FILE *fp)
|
|
{
|
|
fprintf(fp, "\"Type\": \"Cylinder\",\n");
|
|
Tuple t = this->transformMatrix * Point(0, 0, 0);
|
|
fprintf(fp, "\"pseudocenter\": { \"x\": %f, \"y\": %f, \"z\": %f}, \n",
|
|
t.x, t.y, t.z);
|
|
t = this->transformMatrix * Point(0, this->minCap, 0);
|
|
fprintf(fp, "\"min\": %f, \n", t.y);
|
|
t = this->transformMatrix * Point(1, this->maxCap, 1);
|
|
fprintf(fp, "\"max\": %f, \n", t.y);
|
|
Shape::dumpMe(fp);
|
|
} |