text: // 3D Cube Rotation
  // http://www.speich.net/computer/moztesting/3d.htm
  // Created by Simon Speich
  
  var Q = new Array();
  var MTrans = new Array();  // transformation matrix
  var MQube = new Array();  // position information of qube
  var I = new Array();      // entity matrix
  var Origin = new Object();
  var Testing = new Object();
  var LoopTimer;
  
  var DisplArea = new Object();
  DisplArea.Width = 300;
  DisplArea.Height = 300;
  
  function DrawLine(From, To) {
    var x1 = From.V[0];
    var x2 = To.V[0];
    var y1 = From.V[1];
    var y2 = To.V[1];
    var dx = Math.abs(x2 - x1);
    var dy = Math.abs(y2 - y1);
    var x = x1;
    var y = y1;
    var IncX1, IncY1;
    var IncX2, IncY2;  
    var Den;
    var Num;
    var NumAdd;
    var NumPix;
  
    if (x2 >= x1) {  IncX1 = 1; IncX2 = 1;  }
    else { IncX1 = -1; IncX2 = -1; }
    if (y2 >= y1)  {  IncY1 = 1; IncY2 = 1; }
    else { IncY1 = -1; IncY2 = -1; }
    if (dx >= dy) {
      IncX1 = 0;
      IncY2 = 0;
      Den = dx;
      Num = dx / 2;
      NumAdd = dy;
      NumPix = dx;
    }
    else {
      IncX2 = 0;
      IncY1 = 0;
      Den = dy;
      Num = dy / 2;
      NumAdd = dx;
      NumPix = dy;
    }
  
    NumPix = Math.round(Q.LastPx + NumPix);
  
    var i = Q.LastPx;
    for (; i < NumPix; i++) {
      Num += NumAdd;
      if (Num >= Den) {
        Num -= Den;
        x += IncX1;
        y += IncY1;
      }
      x += IncX2;
      y += IncY2;
    }
    Q.LastPx = NumPix;
  }
  
  function CalcCross(V0, V1) {
    var Cross = new Array();
    Cross[0] = V0[1]*V1[2] - V0[2]*V1[1];
    Cross[1] = V0[2]*V1[0] - V0[0]*V1[2];
    Cross[2] = V0[0]*V1[1] - V0[1]*V1[0];
    return Cross;
  }
  
  function CalcNormal(V0, V1, V2) {
    var A = new Array();   var B = new Array(); 
    for (var i = 0; i < 3; i++) {
      A[i] = V0[i] - V1[i];
      B[i] = V2[i] - V1[i];
    }
    A = CalcCross(A, B);
    var Length = Math.sqrt(A[0]*A[0] + A[1]*A[1] + A[2]*A[2]); 
    for (var i = 0; i < 3; i++) A[i] = A[i] / Length;
    A[3] = 1;
    return A;
  }
  
  function CreateP(X,Y,Z) {
    this.V = [X,Y,Z,1];
  }
  
  // multiplies two matrices
  function MMulti(M1, M2) {
    var M = [[],[],[],[]];
    var i = 0;
    var j = 0;
    for (; i < 4; i++) {
      j = 0;
      for (; j < 4; j++) M[i][j] = M1[i][0] * M2[0][j] + M1[i][1] * M2[1][j] + M1[i][2] * M2[2][j] + M1[i][3] * M2[3][j];
    }
    return M;
  }
  
  //multiplies matrix with vector
  function VMulti(M, V) {
    var Vect = new Array();
    var i = 0;
    for (;i < 4; i++) Vect[i] = M[i][0] * V[0] + M[i][1] * V[1] + M[i][2] * V[2] + M[i][3] * V[3];
    return Vect;
  }
  
  function VMulti2(M, V) {
    var Vect = new Array();
    var i = 0;
    for (;i < 3; i++) Vect[i] = M[i][0] * V[0] + M[i][1] * V[1] + M[i][2] * V[2];
    return Vect;
  }
  
  // add to matrices
  function MAdd(M1, M2) {
    var M = [[],[],[],[]];
    var i = 0;
    var j = 0;
    for (; i < 4; i++) {
      j = 0;
      for (; j < 4; j++) M[i][j] = M1[i][j] + M2[i][j];
    }
    return M;
  }
  
  function Translate(M, Dx, Dy, Dz) {
    var T = [
    [1,0,0,Dx],
    [0,1,0,Dy],
    [0,0,1,Dz],
    [0,0,0,1]
    ];
    return MMulti(T, M);
  }
  
  function RotateX(M, Phi) {
    var a = Phi;
    a *= Math.PI / 180;
    var Cos = Math.cos(a);
    var Sin = Math.sin(a);
    var R = [
    [1,0,0,0],
    [0,Cos,-Sin,0],
    [0,Sin,Cos,0],
    [0,0,0,1]
    ];
    return MMulti(R, M);
  }
  
  function RotateY(M, Phi) {
    var a = Phi;
    a *= Math.PI / 180;
    var Cos = Math.cos(a);
    var Sin = Math.sin(a);
    var R = [
    [Cos,0,Sin,0],
    [0,1,0,0],
    [-Sin,0,Cos,0],
    [0,0,0,1]
    ];
    return MMulti(R, M);
  }
  
  function RotateZ(M, Phi) {
    var a = Phi;
    a *= Math.PI / 180;
    var Cos = Math.cos(a);
    var Sin = Math.sin(a);
    var R = [
    [Cos,-Sin,0,0],
    [Sin,Cos,0,0],
    [0,0,1,0],   
    [0,0,0,1]
    ];
    return MMulti(R, M);
  }
  
  function DrawQube() {
    // calc current normals
    var CurN = new Array();
    var i = 5;
    Q.LastPx = 0;
    for (; i > -1; i--) CurN[i] = VMulti2(MQube, Q.Normal[i]);
    if (CurN[0][2] < 0) {
      if (!Q.Line[0]) { DrawLine(Q[0], Q[1]); Q.Line[0] = true; };
      if (!Q.Line[1]) { DrawLine(Q[1], Q[2]); Q.Line[1] = true; };
      if (!Q.Line[2]) { DrawLine(Q[2], Q[3]); Q.Line[2] = true; };
      if (!Q.Line[3]) { DrawLine(Q[3], Q[0]); Q.Line[3] = true; };
    }
    if (CurN[1][2] < 0) {
      if (!Q.Line[2]) { DrawLine(Q[3], Q[2]); Q.Line[2] = true; };
      if (!Q.Line[9]) { DrawLine(Q[2], Q[6]); Q.Line[9] = true; };
      if (!Q.Line[6]) { DrawLine(Q[6], Q[7]); Q.Line[6] = true; };
      if (!Q.Line[10]) { DrawLine(Q[7], Q[3]); Q.Line[10] = true; };
    }
    if (CurN[2][2] < 0) {
      if (!Q.Line[4]) { DrawLine(Q[4], Q[5]); Q.Line[4] = true; };
      if (!Q.Line[5]) { DrawLine(Q[5], Q[6]); Q.Line[5] = true; };
      if (!Q.Line[6]) { DrawLine(Q[6], Q[7]); Q.Line[6] = true; };
      if (!Q.Line[7]) { DrawLine(Q[7], Q[4]); Q.Line[7] = true; };
    }
    if (CurN[3][2] < 0) {
      if (!Q.Line[4]) { DrawLine(Q[4], Q[5]); Q.Line[4] = true; };
      if (!Q.Line[8]) { DrawLine(Q[5], Q[1]); Q.Line[8] = true; };
      if (!Q.Line[0]) { DrawLine(Q[1], Q[0]); Q.Line[0] = true; };
      if (!Q.Line[11]) { DrawLine(Q[0], Q[4]); Q.Line[11] = true; };
    }
    if (CurN[4][2] < 0) {
      if (!Q.Line[11]) { DrawLine(Q[4], Q[0]); Q.Line[11] = true; };
      if (!Q.Line[3]) { DrawLine(Q[0], Q[3]); Q.Line[3] = true; };
      if (!Q.Line[10]) { DrawLine(Q[3], Q[7]); Q.Line[10] = true; };
      if (!Q.Line[7]) { DrawLine(Q[7], Q[4]); Q.Line[7] = true; };
    }
    if (CurN[5][2] < 0) {
      if (!Q.Line[8]) { DrawLine(Q[1], Q[5]); Q.Line[8] = true; };
      if (!Q.Line[5]) { DrawLine(Q[5], Q[6]); Q.Line[5] = true; };
      if (!Q.Line[9]) { DrawLine(Q[6], Q[2]); Q.Line[9] = true; };
      if (!Q.Line[1]) { DrawLine(Q[2], Q[1]); Q.Line[1] = true; };
    }
    Q.Line = [false,false,false,false,false,false,false,false,false,false,false,false];
    Q.LastPx = 0;
  }
  
  function Loop() {
    if (Testing.LoopCount > Testing.LoopMax) return;
    var TestingStr = String(Testing.LoopCount);
    while (TestingStr.length < 3) TestingStr = "0" + TestingStr;
    MTrans = Translate(I, -Q[8].V[0], -Q[8].V[1], -Q[8].V[2]);
    MTrans = RotateX(MTrans, 1);
    MTrans = RotateY(MTrans, 3);
    MTrans = RotateZ(MTrans, 5);
    MTrans = Translate(MTrans, Q[8].V[0], Q[8].V[1], Q[8].V[2]);
    MQube = MMulti(MTrans, MQube);
    var i = 8;
    for (; i > -1; i--) {
      Q[i].V = VMulti(MTrans, Q[i].V);
    }
    DrawQube();
    Testing.LoopCount++;
    Loop();
  }
  
  function Init(CubeSize) {
    // init/reset vars
    Origin.V = [150,150,20,1];
    Testing.LoopCount = 0;
    Testing.LoopMax = 50;
    Testing.TimeMax = 0;
    Testing.TimeAvg = 0;
    Testing.TimeMin = 0;
    Testing.TimeTemp = 0;
    Testing.TimeTotal = 0;
    Testing.Init = false;
  
    // transformation matrix
    MTrans = [
    [1,0,0,0],
    [0,1,0,0],
    [0,0,1,0],
    [0,0,0,1]
    ];
    
    // position information of qube
    MQube = [
    [1,0,0,0],
    [0,1,0,0],
    [0,0,1,0],
    [0,0,0,1]
    ];
    
    // entity matrix
    I = [
    [1,0,0,0],
    [0,1,0,0],
    [0,0,1,0],
    [0,0,0,1]
    ];
    
    // create qube
    Q[0] = new CreateP(-CubeSize,-CubeSize, CubeSize);
    Q[1] = new CreateP(-CubeSize, CubeSize, CubeSize);
    Q[2] = new CreateP( CubeSize, CubeSize, CubeSize);
    Q[3] = new CreateP( CubeSize,-CubeSize, CubeSize);
    Q[4] = new CreateP(-CubeSize,-CubeSize,-CubeSize);
    Q[5] = new CreateP(-CubeSize, CubeSize,-CubeSize);
    Q[6] = new CreateP( CubeSize, CubeSize,-CubeSize);
    Q[7] = new CreateP( CubeSize,-CubeSize,-CubeSize);
    
    // center of gravity
    Q[8] = new CreateP(0, 0, 0);
    
    // anti-clockwise edge check
    Q.Edge = [[0,1,2],[3,2,6],[7,6,5],[4,5,1],[4,0,3],[1,5,6]];
    
    // calculate squad normals
    Q.Normal = new Array();
    for (var i = 0; i < Q.Edge.length; i++) Q.Normal[i] = CalcNormal(Q[Q.Edge[i][0]].V, Q[Q.Edge[i][1]].V, Q[Q.Edge[i][2]].V);
    
    // line drawn ?
    Q.Line = [false,false,false,false,false,false,false,false,false,false,false,false];
    
    // create line pixels
    Q.NumPx = 9 * 2 * CubeSize;
    for (var i = 0; i < Q.NumPx; i++) CreateP(0,0,0);
    
    MTrans = Translate(MTrans, Origin.V[0], Origin.V[1], Origin.V[2]);
    MQube = MMulti(MTrans, MQube);
  
    var i = 0;
    for (; i < 9; i++) {
      Q[i].V = VMulti(MTrans, Q[i].V);
    }
    DrawQube();
    Testing.Init = true;
    Loop();
  }
  
  for ( var i = 20; i <= 160; i *= 2 ) {
    Init(i);
  }
  
  var actual = '';
  for (var i = 0; i < Q.length; ++i) {
    actual += Q[i].V + ';';
  }
  var expected = "-116.618229186398,212.51135212951073,62.5094191967962,1;127.83701023614447,417.11611179082263,90.41153816299942,1;293.9570894432935,196.58093046570656,252.17789153139591,1;49.501850020750915,-8.02382919560505,224.275772565193,1;6.042910556709444,103.41906953429206,-212.1778915313964,1;250.49814997925202,308.02382919560387,-184.27577256519325,1;416.61822918640064,87.48864787048812,-22.509419196796493,1;172.1629897638581,-117.1161117908236,-50.41153816299975,1;150.0000000000007,149.99999999999952,20,1;";
  assertEq(actual, expected);
  
  Q = null;
  MTrans = null;
  MQube = null;
  I = null;
  Origin = null;
  Testing = null;
  LoopTime = null;
  DisplArea = null;
  
  