// -------------------------------------
//  Demo for stereo pictures (red/blue)
// -------------------------------------
 
//  image size

height=500;
width =500;

//  fix rotation

rot_x= 0.2;
rot_y=-0.33;
rot_z=-3.33;

//  fix scaling

double sf = 0.35;
scale_x=sf;
scale_y=sf;
scale_z=sf;

// fix position and perspective

spec_z = 25.0;
perspective=central;
antialiasing=4;
radius=7.0;

// fix surface color

surface_red=255;
surface_green=255;
surface_blue=200;
inside_red=255;
inside_green=255;
inside_blue=200;

// fix stereopicture

stereo_eye=1.2;

// vary these values to adjust the
// picture to your 3D-glasses

stereo_red  =1.0; 
stereo_blue =1.0;    // for red/green set to 0.0
//stereo_green =0.8  // for red/green set  > 0.0

// fix light

ambient=10;
smoothness=30;
 
light1_x=1000;
light1_y=1000;
light1_z=1000;
light1_vol=70;
 
light3_x=-1000;
light3_y=200;
light3_z=500;
light3_vol=50;
 
light8_x=0;
light8_y=-1000;
light8_z=1000;
light8_vol=30;

// define the sextic
 
double t=(1+sqrt(5))/2;
 
poly f1=t^2*x^2-y^2;
poly f2=t^2*y^2-z^2;
poly f3=t^2*z^2-x^2;
 
poly g =(x^2+y^2+z^2-1)^2;
 
surface=-(4*f1*f2*f3-(1+2*t)*g);

epsilon=0.0001;
iterations=30;

// draw it

clear_screen;
draw_surface;