nuclear@3: /*
nuclear@3: Simple introductory ray tracer
nuclear@3: Copyright (C) 2012  John Tsiombikas <nuclear@member.fsf.org>
nuclear@3: 
nuclear@3: This program is free software: you can redistribute it and/or modify
nuclear@3: it under the terms of the GNU General Public License as published by
nuclear@3: the Free Software Foundation, either version 3 of the License, or
nuclear@3: (at your option) any later version.
nuclear@3: 
nuclear@3: This program is distributed in the hope that it will be useful,
nuclear@3: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@3: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@3: GNU General Public License for more details.
nuclear@3: 
nuclear@3: You should have received a copy of the GNU General Public License
nuclear@3: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@3: */
nuclear@2: #include "cone.h"
nuclear@2: 
nuclear@2: Cone::Cone()
nuclear@2: {
nuclear@2: 	angle = M_PI / 4.0;
nuclear@2: 	ymin = 0.0f;
nuclear@2: 	ymax = 1.0f;
nuclear@2: }
nuclear@2: 
nuclear@2: Cone::Cone(float angle, float ymin, float ymax)
nuclear@2: {
nuclear@2: 	this->angle = angle;
nuclear@2: 	this->ymin = ymin;
nuclear@2: 	this->ymax = ymax;
nuclear@2: }
nuclear@2: 
nuclear@3: #define SQ(x)	((x) * (x))
nuclear@3: bool Cone::intersect(const Ray &inray, HitPoint *pt) const
nuclear@2: {
nuclear@3: 	Ray ray = inray.transformed(inv_xform);
nuclear@3: 
nuclear@3: 	float slope = 2.0 * angle / M_PI;
nuclear@3: 
nuclear@3: 	float a = SQ(ray.dir.x) - SQ(slope * ray.dir.y) + SQ(ray.dir.z);
nuclear@3: 	float b = 2.0 * ray.origin.x * ray.dir.x - 2.0 * SQ(slope) * ray.origin.y * ray.dir.y +
nuclear@3: 		2.0 * ray.origin.z * ray.dir.z;
nuclear@3: 	float c = SQ(ray.origin.x) - SQ(slope * ray.origin.y) + SQ(ray.origin.z);
nuclear@3: 
nuclear@3: 	float discr = b * b - 4.0 * a * c;
nuclear@3: 	if(discr < 1e-4)
nuclear@3: 		return false;
nuclear@3: 
nuclear@3: 	float sqrt_discr = sqrt(discr);
nuclear@3: 	float t0 = (-b + sqrt_discr) / (2.0 * a);
nuclear@3: 	float t1 = (-b - sqrt_discr) / (2.0 * a);
nuclear@3: 
nuclear@3: 	if(t0 < 1e-4)
nuclear@3: 		t0 = t1;
nuclear@3: 	if(t1 < 1e-4)
nuclear@3: 		t1 = t0;
nuclear@3: 
nuclear@3: 	float t = t0 < t1 ? t0 : t1;
nuclear@3: 	if(t < 1e-4)
nuclear@3: 		return false;
nuclear@3: 
nuclear@3: 	// fill the HitPoint structure
nuclear@3: 	pt->obj = this;
nuclear@3: 	pt->dist = t;
nuclear@3: 	pt->pos = ray.origin + ray.dir * t;
nuclear@3: 
nuclear@3: 	pt->normal.z = sin(angle);
nuclear@3: 
nuclear@3: 	//pt->normal = (pt->pos - pos) / radius; TODO continue here
nuclear@3: 
nuclear@3: 	pt->pos.transform(xform);
nuclear@3: 	pt->normal.transform(dir_xform);
nuclear@2: }