#version unofficial MegaPov 0.5;

/*
A brilliant cut diamond
There are four divisions along the axis at which facets have their endpoints
The third from bottom up is the girdle; below and above the girdle is the crown 
and the pavilion respectively, each divided in two by CrownShape and PavilionShape

Sigmund Kyrre Ås <c> 2000
*/

$ant1=Facets;
$R3=Radius;
$Y2=CrownShape*GirdleHeight;
$Y3=GirdleHeight;
$R1=.46*R3;
$W=2*pi/ant1;
$R2=(R3*Y2-R1*(Y2-Y3))/Y3 * (1+2*sqr(sin(W/4)));

$Y5=TotalHeight;
$Y4=Y3+(Y5-Y3)*PavilionShape;
$R4=(Y5-Y4)*R3/(Y5-Y3) * (1+2*sqr(sin(W/4))) ;

$P=array[4][ant1*2+1] $i=0;
#while (i<ant1+1)
    $P[0][i]=vtransform(<R1,0,0>,rotate y*360*(i/ant1+1/2/ant1));
    $P[1][i]=vtransform(<R2,Y2,0>,rotate y*360*i/ant1);
    $P[3][i]=vtransform(<R4,Y4,0>,rotate y*360*(i/ant1+1/2/ant1));
    $i=i+1;
#end
$i=0;$ant2=ant1*2;
#while (i<ant2+1)
    $P[2][i]=vtransform(<R3,Y3,0>,rotate y*360*i/ant2);
    $i=i+1;
#end

$Diamond=
mesh {
    $j=0;
    #while (j<ant1)
        // crown:
        triangle {P[0][j],    P[0][1+j],  0 } 
        triangle {P[0][j],    P[1][1+j],  P[0][1+j] }
        triangle {P[1][j],    P[0][j],    P[1][j+1] }
        triangle {P[1][j],    P[2][j*2+1],P[1][1+j] }
        triangle {P[2][j*2],  P[1][j],    P[2][j*2+1] }
        triangle {P[2][j*2+1],P[1][j+1],  P[2][j*2+2] }
        // pavilion:
        triangle {P[2][j*2],  P[3][j],  P[2][j*2+1] }
        triangle {P[2][j*2+1],P[3][j],  P[2][j*2+2] }
        triangle {P[3][j],    P[3][j+1],P[2][j*2+2] }
        triangle {P[3][j],    P[3][j+1],Y5*y }
        $j=j+1;
    #end
}