function z(){function o(o,r,y,x){var t,n,f,s,c,g,u,d=Array(l),b=[],m=h[o],p=h[y],v={x:(r+i[o])*h[o].x,y:(r+i[o])*h[o].y},w={x:(x+i[y])*h[y].x,y:(x+i[y])*h[y].y},f=-m.y/m.x,z=-f*v.y+v.x,X=-p.x/p.y,Y=-X*w.x+w.y,A=(X*z+Y)/(1-X*f),I=f*A+z,M={x:I,y:A};for(s=0;l>s;s++)c=h[s],c.x||(g=c.y,c.y=c.x,c.x=g),f=-c.y/c.x,d[s]=e.floor((M.x-f*M.y)/(-f*c.y+c.x)-i[s]);for(t=r+1;t-->r-1;)for(n=x+1;n-->x-1;){for(d[o]=t,d[y]=n,u={x:0,y:0},s=l;s-->0;)u.x+=d[s]*h[s].x,u.y+=d[s]*h[s].y;b.push(u)}a.beginPath(),a.moveTo(b[0].x,b[0].y),[1,3,2].forEach(function(o){a.lineTo(b[o].x,b[o].y)}),a.globalAlpha=.6,a.fillStyle="#00"+e.floor(15*(o+y)/(2*l-3)).toString(16),a.fill()}a.restore(),X=b.clientWidth,Y=window.innerHeight-4,c.width=X,c.height=Y,a.translate(X/2,Y/2),a.scale(55,55);var r,y,x,t,n,f,i=[],e=Math,l=3+2*(0|3*Math.random()),h=[];for(n=l;n-->0;)f=e.PI*(.5+2*n/l),h.push({x:-e.sin(f),y:e.cos(f)}),i.push(e.random());for(r=l;r-->0;)for(y=l;y-->0;)if(y-r)for(x=9;x-->-8;)for(t=9;t-->-8;)o(r,x,y,t)}b.style.margin=0,z(),setInterval(z,3e3);
// var b = document.body;
// var c = document.getElementsByTagName('canvas')[0];
// var a = c.getContext('2d');
b.style.margin=0;
function z(){
a.restore();
X=b.clientWidth,Y=window.innerHeight-4;
c.width=X;c.height=Y; // setting width, clears a.clearRect(-X,-Y,2*X,2*Y)
a.translate(X/2,Y/2);
a.scale(55,55);
// setup and declarations
var i0,i1,n0,n1,
g=[],i,M=Math,rad,
eDim = 3+2*(Math.random()*3|0), // rnd 3,5,7
e = []; // basis vectors
for (i=eDim;i-->0;) {
rad=M.PI*(.5+2*i/eDim);
e.push({x:-M.sin(rad),y:M.cos(rad)})
g.push(M.random());
}
// main loop
for (i0=eDim;i0-->0;)
for (i1=eDim;i1-->0;)
if (i1-i0)
for (n0=9;n0-->-8;)
for (n1=9;n1-->-8;)
intersectAndRhomb(i0,n0,i1,n1);
//
function intersectAndRhomb(i0,n0,i1,n1){
var n=Array(eDim),//[null,null,null,null,null];
ni0,ni1,
// inline intersection
// intr = intersect(i0,n0,i1,n1),
rh=[],A,i,ei,s,p,
e0 = e[i0],
e1 = e[i1],
n0g0e0 = {x:(n0+g[i0])*e[i0].x, y:(n0+g[i0])*e[i0].y},
n1g1e1 = {x:(n1+g[i1])*e[i1].x, y:(n1+g[i1])*e[i1].y},
A = -e0.y/e0.x,
B = -A*n0g0e0.y + n0g0e0.x,
C = -e1.x/e1.y,
D = -C*n1g1e1.x + n1g1e1.y,
y = ( C*B + D ) / (1-C*A),
x = A*y + B,
intr = {x:x,y:y};
// now we have a cube, cast a shadow.
for (i=0;i<eDim;i++){
ei=e[i];
if (!ei.x){ s=ei.y;ei.y=ei.x;ei.x=s}
A= -ei.y/ei.x;
n[i] = M.floor((intr.x-A*intr.y)/(-A*ei.y+ei.x)-g[i]);
}
for (ni0=n0+1;ni0-->n0-1;) {
for (ni1=n1+1;ni1-->n1-1;) {
n[i0]=ni0;
n[i1]=ni1;
p = { x:0, y:0 };
for (i=eDim;i-->0;) {
p.x+= n[i]*e[i].x;
p.y+= n[i]*e[i].y;
}
rh.push(p);
}
}
// inline drawRhomb(rh,i0,i1);
a.beginPath(); // path: 0,1,3,2
a.moveTo(rh[0].x,rh[0].y);
[1,3,2].forEach(function(j){
a.lineTo(rh[j].x,rh[j].y);
})
a.globalAlpha=0.6;
// blue range: i0+i1: min 1, max eDim-1+eDim-2
a.fillStyle='#00'+M.floor(15*(i0+i1)/(2*eDim-3)).toString(16);
a.fill();
}
}
z(); setInterval(z,3000);
