Fix quadrics flipped near/far

[mjy9088]

miniRT/src/t/ray/nearest/t_ray_nearest_quadric.c

Lines 79 to 88 in a286071

	*out_distance = (-eq.b - t_f_sqrt(discriminant)) / (2 * eq.a);
	if (*out_distance > 0)
	*out_is_front_face = true;
	else
	{
	*out_distance = (-eq.b + t_f_sqrt(discriminant)) / (2 * eq.a);
	if (*out_distance < 0)
	return (false);
	*out_is_front_face = false;
	}

miniRT/src/t/ray/primitive/ellipsoid/t_ray_primitive_ellipsoid_outside.c

Lines 47 to 93 in a286071

	static t_err front(t_vars l, t_ray ray, t_ray_hit_records_builder *builder)
	{
	const t_f distance = (-l.y - l.sqrt_y2_4xz) / (2 * l.x);
	const t_map_position point
	= t_f3_add(ray.origin, t_f3_mul(ray.direction, distance));
	t_map_normal normal;
	t_f coord_x;
	t_f coord_y;
	if (distance <= 0)
	return (false);
	normal = t_ray_primitive_ellipsoid_normal(l, point);
	t_ray_primitive_ellipsoid_coord(point, l.self.size, &coord_x, &coord_y);
	return (
	t_ray_hit_records_builder_add(builder, (t_ray_hit_record){
	distance,
	normal,
	t_ray_material_from_color(l.self.material),
	true,
	coord_x,
	coord_y,
	})
	);
	}
	static t_err back(t_vars l, t_ray ray, t_ray_hit_records_builder *builder)
	{
	const t_f distance = (-l.y + l.sqrt_y2_4xz) / (2 * l.x);
	const t_map_position point
	= t_f3_add(ray.origin, t_f3_mul(ray.direction, distance));
	t_map_normal normal;
	t_f coord_x;
	t_f coord_y;
	normal = t_ray_primitive_ellipsoid_normal(l, point);
	t_ray_primitive_ellipsoid_coord(point, l.self.size, &coord_x, &coord_y);
	return (
	t_ray_hit_records_builder_add(builder, (t_ray_hit_record){
	distance,
	normal,
	t_ray_material_from_color(l.self.material),
	false,
	coord_x,
	coord_y,
	})
	);
	}

miniRT/src/t/ray/primitive/cylinder/t_ray_primitive_cylinder_side.c

Lines 63 to 72 in a286071

	l.n_distance = (-a.y - a.sqrt_y2_4xz) / (2 * a.x);
	l.n = t_f3_add(ray.origin, t_f3_mul(ray.direction, l.n_distance));
	l.n_hit = (l.n_distance >= 0 && l.n.z >= 0 && l.n.z <= a.self.size.z);
	if (l.n_hit)
	{
	l.n_normal = t_ray_primitive_cylinder_side_normal(a, l.n);
	l.n_x = t_f_rot(t_f_atan2(l.n.y, l.n.x));
	l.n_y = l.n.z / a.self.size.z;
	}
	l.f_distance = (-a.y + a.sqrt_y2_4xz) / (2 * a.x);

miniRT/src/t/ray/primitive/cone/t_ray_primitive_cone_side.c

Lines 66 to 75 in a286071

	l.n_distance = (-a.y - a.sqrt_y2_4xz) / (2 * a.x);
	l.n = t_f3_add(ray.origin, t_f3_mul(ray.direction, l.n_distance));
	l.n_hit = (l.n_distance >= 0 && l.n.z >= 0 && l.n.z <= a.self.size.z);
	if (l.n_hit)
	{
	l.n_normal = t_ray_primitive_cone_side_normal(a, l.n);
	l.n_x = t_f_rot(t_f_atan2(l.n.y, l.n.x));
	l.n_y = l.n.z / a.self.size.z;
	}
	l.f_distance = (-a.y + a.sqrt_y2_4xz) / (2 * a.x);

If eq.a (or l.x, a.x) is negative, near/far is flipped.