cylinder.c

#include "objects.h"
#include "operations.h"
#include "cylinder.h"
#include "polygon.h"
#include <math.h>
#include <stdio.h>

OBJECT createCylinder(double radius, POINT anchor, VECTOR axis, double d1, double d2, COLOR color, long double kd, long double ka,
					  long double kn, long double ks, long double o1, long double o2){
	CYLINDER cylinder;
	cylinder.radius = radius;
	cylinder.anchor = anchor; 			   // ANCLA
	cylinder.axis = normalizeVector(axis); // EJE
	cylinder.d1 = d1;		 			   // TAPA 1
	cylinder.d2 = d2;	     			   // TAPA 2
	cylinder.G = getG(cylinder.axis);

	VECTOR temp = cruxProduct(cylinder.G, cylinder.axis);
	double d = getD(temp, cylinder.anchor);
	double magnitude = getMagnitude(temp);
	temp = normalizeVector(temp);
	d = d / magnitude;
	cylinder.equation.a = temp.x;
	cylinder.equation.b = temp.y;
	cylinder.equation.c = temp.z;
	cylinder.equation.d = d;



	OBJECT newObject;
	newObject.id = 'C';
	newObject.cylinder = cylinder;
	newObject.color = color;
	newObject.ka = ka;
	newObject.kd = kd;
	newObject.ks = ks;
	newObject.kn = kn;
	newObject.o1 = o1;
	newObject.o2 = o2;

	return newObject;
}

bool verifyFinitePoint(POINT intersectionPoint, double d1, double d2, POINT o, VECTOR q){
	double d = (intersectionPoint.x - o.x)*q.x + (intersectionPoint.y - o.y)*q.y + (intersectionPoint.z - o.z)*q.z;
	if(d1 <= d && d <= d2){
		return true;
	}
	return false;
}

INTERSECTION findIntersection_cylinder(VECTOR d, POINT e, POINT o, double radius, VECTOR q, double d1, double d2){
	// d es direction, e es ojo, o es el ancla, q es el eje. Se puso así para que la formula no quede enorme
    INTERSECTION intersection;

	long double var1,var2,var3,var4,var5,var6;

	var1 = (pow(q.x,2)*d.x)+(q.x*d.y*q.y)+(q.x*d.z*q.z)-d.x;
	var2 = (pow(q.y,2)*d.y)+(d.x*q.x*q.y)+(q.y*d.z*q.z)-d.y;
	var3 = (pow(q.z,2)*d.z)+(d.x*q.x*q.z)+(d.y*q.y*q.z)-d.z;
	var4 = (e.x-o.x);
	var5 = (e.y-o.y);
	var6 = (e.z-o.z);


	double a = pow(var1,2)+pow(var2,2)+pow(var3,2);

	double b = (2*var1*var4*(pow(q.x,2)-1))+(2*var1*q.x*((q.y*var5)+(q.z*var6)))
	+(2*var2*var5*(pow(q.y,2)-1))+(2*var2*q.y*((q.x*var4)+(q.z*var6)))
	+(2*var3*var6*(pow(q.z,2)-1))+(2*var3*q.z*((q.x*var4)+(q.y*var5)));

	double c = pow(((pow(q.x,2)-1)*var4),2)+pow((q.x*((q.y*var5)+(q.z*var6))),2)
	+pow(((pow(q.y,2)-1)*var5),2)+pow((q.y*((q.x*var4)+(q.z*var6))),2)
	+pow(((pow(q.z,2)-1)*var6),2)+pow((q.z*((q.x*var4)+(q.y*var5))),2)
	+(2*var4*q.x*(pow(q.x,2)-1)*((q.y*var5)+(q.z*var6)))
	+(2*var5*q.y*(pow(q.y,2)-1)*((q.x*var4)+(q.z*var6)))
	+(2*var6*q.z*(pow(q.z,2)-1)*((q.x*var4)+(q.y*var5)))-pow(radius,2);

    double discriminante = pow(b, 2) - 4*a*c;

	if(discriminante < EPSILON){ // No hay interseccion con el cilindro INFINITO
		intersection.tmin = 0;
		intersection.tmax = 0;
		intersection.flag = 0;
	}
	else{
		if(discriminante > EPSILON){ // Hay dos intersecciones
			double t1 = (-b + sqrt(discriminante))/(2.0*a);
			double t2 = (-b - sqrt(discriminante))/(2.0*a);


			if(t1 < t2){
				intersection.tmin = t1;
				intersection.tmax = t2;
			}
			else{
				intersection.tmin = t2;
				intersection.tmax = t1;
			}
			intersection.flag = 1;
		}
		else{ // Hay una interseccion
			double temp = (-b + sqrt(discriminante))/(2.0*a);

			if(temp != EPSILON){
				intersection.tmin = temp;
			}
			else{
				intersection.tmin = (-b - sqrt(discriminante))/(2.0*a);
			}
			intersection.tmax = 0;
			intersection.flag = 1;
		}

		if(!verifyFinitePoint(getIntersectionPoint(pointToVector(e), d, intersection.tmin), d1, d2, o, q)){ // No hay intersección con el FINITO

			if(verifyFinitePoint(getIntersectionPoint(pointToVector(e), d, intersection.tmax), d1, d2, o, q)){
				intersection.tmin = intersection.tmax;
				intersection.tmax = 0;
				intersection.flag = 1;
			}
			else{
				intersection.tmin = 0;
				intersection.tmax = 0;
				intersection.flag = 0;
			}
		}

	}
	return intersection;
}