53 lines
1.8 KiB
C
53 lines
1.8 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* maths_cylinder.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: gbrochar <marvin@42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2019/02/08 18:31:29 by gbrochar #+# #+# */
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/* Updated: 2019/02/22 17:26:27 by gbrochar ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "rtv1.h"
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double intersect_cylinder(void *obj, t_ray r)
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{
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t_cylinder *cy;
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t_vec sub_ori;
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double roots[2];
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double params[3];
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cy = (t_cylinder *)obj;
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sub_ori = vec_sub(r.o, cy->o);
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params[0] = dot_product(r.d, r.d) - pow(dot_product(r.d, cy->d), 2);
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params[1] = (double)2 * (dot_product(r.d, sub_ori)
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- (dot_product(r.d, cy->d) * dot_product(sub_ori, cy->d)));
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params[2] = dot_product(sub_ori, sub_ori)
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- pow(dot_product(sub_ori, cy->d), 2) - pow(cy->r, 2);
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if (SUCCESS == solve_quadratic(params, roots))
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{
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if (roots[0] > 0)
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return (roots[0] - E);
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else if (roots[1] > 0)
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return (roots[1] - E);
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}
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return (FAILURE);
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}
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t_vec normal_cylinder(void *obj, t_ray r, double t)
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{
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t_cylinder *cy;
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t_vec p;
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double m;
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cy = (t_cylinder *)obj;
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p = vec_add(r.o, vec_mul(r.d, t));
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m = dot_product(r.d, cy->d) * t
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+ dot_product(vec_sub(r.o, cy->o), cy->d);
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p = vec_sub(vec_sub(p, cy->o), vec_mul(cy->d, m));
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normalize(&p);
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return (p);
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}
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