#version 3.8;

global_settings {assumed_gamma 1.0}

camera {
	location <0, -1, -15>
	look_at <0, 0, 0> 
	right x*image_width/image_height 
	up y 
}

sky_sphere {pigment {rgb 1} }

light_source {<10, 10, -10> rgb 1}

/*
f_polytubes(x,y,z, P0, P1, P2, P3, P4, P5): The Polytubes surface consists of a number of tubes. 
Each tube follows a 2d curve which is specified by a polynomial of degree 4 or less. 
If we look at the parameters, then this function generates P0 tubes which all follow the equation x = P1 + P2y + P3y2 + P4y3 + P5y4 arranged around the Y axis. This function needs a positive threshold (fatness of the tubes).

P0 : Number of tubes
P1 : Constant
P2 : Y coefficient
P3 : Y2 coefficient
P4 : Y3 coefficient
P5 : Y4 coefficient
*/

#include "functions.inc"

isosurface {
	function {
		f_polytubes (
			x,y,z,
			 1,
			-6,
			-5,
			 5,
			 5,
			 1
		)
	}          
	contained_by {sphere {<0,0,0>, 8}}
	threshold 0.5
	max_gradient 1100
	accuracy 0.0001
	texture {
		pigment{rgb <1,0.75,0.00>} 
		//normal { bumps 0.15 scale 0.015}
		finish {specular 0.2 phong 0.7 }
	}

	rotate y*90
	rotate z*90
} // end isosurface