function R(){with(Math)var h=a.width,n=a.height,q=[h,n],k=sqrt(27),e=3/k,l=2*e/h*n,k=[-l,-2/3,e,-e,l,-2/3,e,-e,0,4/3,e,-e,0,0,-k,k],e=.5+sqrt(5)/2,e=[0,1,-1,e,-e,1/e,-1/e],l="111221212122300400030040003004013014023024130140230240301302401402112121211222053054063064530540630640305405306406",t=["013021032123","468479487496569578586597",":<B:>@:@D:B>:D<;=E;>C;@>;C=;E@<?B<A?<DA=?A=AE=C?>BC@ED?CBADE","0F2H0G3F0H1GF3I2G1I3H2I1","0JLGR0RTFN0NPHJFK2PNFT3MKGL1QOGO3TRHP2USHS1LJ3OQIM2KMIU1SUIQ"][s],p=3>s?3:
s+1,u=sin(r),v=cos(r),w=t.length/p,d,g,f,m;c.clearRect(0,0,h,n);for(c.fillStyle="#084";w--;){c.beginPath();m=[];for(h=p+1;h--;){d=3*t.charCodeAt(w*p+h%p)-144;g=e[l[d]];f=e[l[d+1]];g=[g*v-f*u,g*u+f*v,e[l[d+2]],1];m[h]=f=[0,0,0,0];for(d in k)f[~~(d/4)]+=g[d%4]*k[~~(d/4)+d%4*4];for(d in q)f[d]=(f[d]/f[3]/2+.5)*q[d];c.lineTo(f[0],n-f[1])}d=m[1];g=m[2];m[0][0]*(d[1]-g[1])+d[0]*g[1]>m[0][1]*(d[0]-g[0])+d[1]*g[0]&&(c.fill(),c.stroke())}r-=.005;requestAnimationFrame(R)}var s=3,r=0;
b.onclick=function(){s=++s%5};R();
function R ()
{
with (Math) {
// eye is [3, 3, 3]
var w = a.width,
h = a.height,
size = [w, h],
eyeDistance = sqrt (27),
eyeDirection = 3 / eyeDistance,
dirWithAspect = eyeDirection * 2 / w * h,
matrix = [ // projection matrix * model view matrix
-dirWithAspect, -2 / 3, eyeDirection, -eyeDirection,
dirWithAspect, -2 / 3, eyeDirection, -eyeDirection,
0, 4 / 3, eyeDirection, -eyeDirection,
0, 0, -eyeDistance, eyeDistance
],
val = .5 + sqrt (5) / 2,
vertexTable = [0, 1, -1, val, -val, 1 / val, -1 / val], // vertex coordinate values
vertices = '111221212122300400030040003004013014023024130140230240301302401402112121211222053054063064530540630640305405306406', // indices to vertexTable
shapes = [ // indices to vertices
'013021032123', // tetrahedron
'468479487496569578586597', // octahedron
':<B:>@:@D:B>:D<;=E;>C;@>;C=;E@<?B<A?<DA=?A=AE=C?>BC@ED?CBADE', // icosahedron
'0F2H0G3F0H1GF3I2G1I3H2I1', // hexahedron
'0JLGR0RTFN0NPHJFK2PNFT3MKGL1QOGO3TRHP2USHS1LJ3OQIM2KMIU1SUIQ' // dodecahedron
],
polygons = shapes[s], // polygons of the current shape
polygonSides = s < 3 ? 3 : s + 1, // polygon vertex count of the current shape
si = sin (r),
co = cos (r),
i = polygons.length / polygonSides,
j, k, l, m, vertex, projected, projectedCoords;
}
// draw shape
c.clearRect (0, 0, w, h);
c.fillStyle = '#084';
while (i--) {
// draw polygons
c.beginPath ();
projectedCoords = [];
j = polygonSides + 1;
while (j--) {
// calculate rotated vertex
k = 3 * polygons.charCodeAt (i * polygonSides + j % polygonSides) - 144;
l = vertexTable[vertices[k]];
m = vertexTable[vertices[k + 1]];
vertex = [l * co - m * si, l * si + m * co, vertexTable[vertices[k + 2]], 1];
// calculate projected coordinate
projectedCoords[j] = projected = [0, 0, 0, 0];
for (k in matrix) { // matrix has 16 elements
projected[~~(k / 4)] += vertex[k % 4] * matrix[~~(k / 4) + k % 4 * 4];
}
for (k in size) { // size has 2 elements
projected[k] = (projected[k] / projected[3] / 2 + .5) * size[k];
}
c.lineTo (projected[0], h - projected[1]);
}
// show only counter clockwise projected polygons
k = projectedCoords[1];
l = projectedCoords[2];
if (projectedCoords[0][0] * (k[1] - l[1]) + k[0] * l[1] > projectedCoords[0][1] * (k[0] - l[0]) + k[1] * l[0]) {
c.fill ();
c.stroke ();
}
}
r -= 0.005;
requestAnimationFrame (R);
}
var s = 3, r = 0;
b.onclick = function ()
{
s = ++s % 5;
};
R ();
