inter_cone.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   inter_cone.c                                       :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: qchevrin <qchevrin@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2014/03/15 19:17:52 by qchevrin          #+#    #+#             */
/*   Updated: 2014/03/26 21:48:58 by qchevrin         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "raytracer.h"

static double	*init_delta(void)
{
	double		*d;

	d = (double *)j_malloc(sizeof(double) * 2);
	d[0] = -1;
	d[1] = -1;
	return (d);
}

static void		update_info(t_info *info, double dist, void *obj, t_line new)
{
	t_cone	*cone;

	info->distance = dist;
	info->obj_type = CONE;
	info->obj = obj;
	cone = (t_cone *)obj;
	info->color = cone->color;
	info->s_line.pos.x = new.pos.x;
	info->s_line.pos.y = new.pos.y;
	info->s_line.pos.z = new.pos.z;
	info->s_line.vec.x = new.vec.x;
	info->s_line.vec.y = new.vec.y;
	info->s_line.vec.z = new.vec.z;
}

static t_line	get_new_equa(t_cone *obj, t_line line)
{
	t_line		new;

	new.pos.x = line.pos.x;
	new.pos.y = line.pos.y;
	new.pos.z = line.pos.z;
	new.vec.x = line.vec.x;
	new.vec.y = line.vec.y;
	new.vec.z = line.vec.z;
	apply_trans(obj->m_i, &new.pos);
	apply_rot(obj->m_i, &new.vec);
	return (new);
}

static double	*delta(t_line new, t_cone *obj)
{
	t_equa		e;
	double		tan_al;
	double		*x;

	x = init_delta();
	tan_al = tan(RAD(obj->alpha));
	tan_al = SQR(tan_al);
	e.a = SQR(new.vec.x) + SQR(new.vec.z) - (SQR(new.vec.y) * tan_al);
	e.b = 2 * (new.vec.x * new.pos.x + new.vec.z * new.pos.z);
	e.b = e.b - (2 * new.vec.y * new.pos.y * tan_al);
	e.c = SQR(new.pos.x) + SQR(new.pos.z) - (SQR(new.pos.y) * tan_al);
	e.delta = SQR(e.b) - 4 * e.a * e.c;
	if (e.delta < -0.00001)
		return (x);
	if (e.delta > -0.00001 && e.delta < 0.00001)
	{
		x[0] = (-e.b / (2 * e.a));
		return (x);
	}
	x[0] = (-e.b - sqrt(e.delta)) / (2 * e.a);
	x[1] = (-e.b + sqrt(e.delta)) / (2 * e.a);
	if (x[0] < x[1] && x[0] > 0)
		return (x);
	swap_double(&(x[0]), &(x[1]));
	return (x);
}

void			inter_cone(t_info *info, t_list *cone)
{
	t_line		new;
	t_cone		*obj;
	double		*dist;

	while (cone)
	{
		obj = (t_cone *)cone->content;
		new = get_new_equa(obj, info->r_line);
		dist = delta(new, obj);
		dist[0] = limited_cone(obj, new, dist);
		if (dist[0] > 0.001 && (info->distance < 0 || dist[0] < info->distance))
			update_info(info, dist[0], cone->content, new);
		cone = cone->next;
	}
}