# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1415556813 -7200
# Node ID 297dbc5080c47d80a0a1a7119621f836e8f55a6b
# Parent  6e3a4daf3159bf9544e40772f2c12eddcdbb3abd
cone intersection

diff -r 6e3a4daf3159 -r 297dbc5080c4 src/cone.cc
--- a/src/cone.cc	Sun Nov 09 14:39:01 2014 +0200
+++ b/src/cone.cc	Sun Nov 09 20:13:33 2014 +0200
@@ -1,3 +1,20 @@
+/*
+Simple introductory ray tracer
+Copyright (C) 2012  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
 #include "cone.h"
 
 Cone::Cone()
@@ -14,7 +31,44 @@
 	this->ymax = ymax;
 }
 
-bool Cone::intersect(const Ray &ray, HitPoint *pt) const
+#define SQ(x)	((x) * (x))
+bool Cone::intersect(const Ray &inray, HitPoint *pt) const
 {
-	return false;	// TODO
+	Ray ray = inray.transformed(inv_xform);
+
+	float slope = 2.0 * angle / M_PI;
+
+	float a = SQ(ray.dir.x) - SQ(slope * ray.dir.y) + SQ(ray.dir.z);
+	float b = 2.0 * ray.origin.x * ray.dir.x - 2.0 * SQ(slope) * ray.origin.y * ray.dir.y +
+		2.0 * ray.origin.z * ray.dir.z;
+	float c = SQ(ray.origin.x) - SQ(slope * ray.origin.y) + SQ(ray.origin.z);
+
+	float discr = b * b - 4.0 * a * c;
+	if(discr < 1e-4)
+		return false;
+
+	float sqrt_discr = sqrt(discr);
+	float t0 = (-b + sqrt_discr) / (2.0 * a);
+	float t1 = (-b - sqrt_discr) / (2.0 * a);
+
+	if(t0 < 1e-4)
+		t0 = t1;
+	if(t1 < 1e-4)
+		t1 = t0;
+
+	float t = t0 < t1 ? t0 : t1;
+	if(t < 1e-4)
+		return false;
+
+	// fill the HitPoint structure
+	pt->obj = this;
+	pt->dist = t;
+	pt->pos = ray.origin + ray.dir * t;
+
+	pt->normal.z = sin(angle);
+
+	//pt->normal = (pt->pos - pos) / radius; TODO continue here
+
+	pt->pos.transform(xform);
+	pt->normal.transform(dir_xform);
 }
diff -r 6e3a4daf3159 -r 297dbc5080c4 src/cone.h
--- a/src/cone.h	Sun Nov 09 14:39:01 2014 +0200
+++ b/src/cone.h	Sun Nov 09 20:13:33 2014 +0200
@@ -1,3 +1,20 @@
+/*
+Simple introductory ray tracer
+Copyright (C) 2012  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
 #ifndef CONE_H_
 #define CONE_H_
 
diff -r 6e3a4daf3159 -r 297dbc5080c4 src/sphere.cc
--- a/src/sphere.cc	Sun Nov 09 14:39:01 2014 +0200
+++ b/src/sphere.cc	Sun Nov 09 20:13:33 2014 +0200
@@ -1,3 +1,20 @@
+/*
+Simple introductory ray tracer
+Copyright (C) 2012  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
 #include <stdio.h>
 #include "sphere.h"