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|
// -------------------------------
// The Clebsch diagonal surface:
// a smooth cubic surface
// admitting the symmetry
// of the tetrahedron
// -------------------------------
// set image size
illumination = ambient_light+diffuse_light+transmitted_light+reflected_light;
width =400;
height=400;
set_size;
curve_red=100;
curve_green=50;
curve_blue=0;
// define some useful constants
double w2=sqrt(2.0);
double Pi=2*arccos(0);
// define tetrahedral coordinates
poly p=1-z-w2*x;
poly q=1-z+w2*x;
poly r=1+z+w2*y;
poly s=1+z-w2*y;
// symmetric polynomials
poly c1=p +q +r -s;
poly c2=p^3+q^3+r^3-s^3;
// fix rotation
first = translate;
second = rotate;
third = scale;
rot_x=-0.5;
rot_y= 4.35;
rot_z=-0.58+Pi;
// fix scaling
double sf = 0.6;
scale_x=sf;
scale_y=sf*0.5;
scale_z=sf;
// visible area and perspective
depth_cueing=yes;
depth=-20;
radius=9;
spec_z=30;
perspective=central;
antialiasing=4;
// fix light
ambient =20;
diffuse =60;
reflected =70;
smoothness=30;
light1_x =-100;
light1_y = 100;
light1_z = 100;
light1_vol= 80;
light3_x = 100;
light3_y = 20;
light3_z = 50;
light3_vol= 60;
light8_x =-100;
light8_y = 100;
light8_z = 100;
light8_vol= 20;
// surface color
// define the diagonal surface
poly clebsch = c2 - c1^3;
surface=clebsch;
// draw the surface
clear_screen;
cutsurface1=rotate(clebsch,1.0,xAxis);
// surface2=cutsurface1;
draw_surface;
curve_width=6;
cut_with_surface;
filename="| rasttopnm | ppmtoxpm >surf.xpm";
color_file_format=sun;
color_file_colormap=Optimized;
save_color_image;
|
