vector.js

// Preventing Pressing of arrow keys from scrolling the page

window.addEventListener("keydown", function(e) {
    // space and arrow keys
    if([32, 37, 38, 39, 40].indexOf(e.keyCode) > -1) {
        e.preventDefault();
    }
}, false);

function matrixMultiply(mat2, mat1)
{
  return [
    mat1[0]*mat2[0]+mat1[1]*mat2[4]+mat1[2]*mat2[8]+mat1[3]*mat2[12],
    mat1[0]*mat2[1]+mat1[1]*mat2[5]+mat1[2]*mat2[9]+mat1[3]*mat2[13],
    mat1[0]*mat2[2]+mat1[1]*mat2[6]+mat1[2]*mat2[10]+mat1[3]*mat2[14],
    mat1[0]*mat2[3]+mat1[1]*mat2[7]+mat1[2]*mat2[11]+mat1[3]*mat2[15],
    mat1[4]*mat2[0]+mat1[5]*mat2[4]+mat1[6]*mat2[8]+mat1[7]*mat2[12],
    mat1[4]*mat2[1]+mat1[5]*mat2[5]+mat1[6]*mat2[9]+mat1[7]*mat2[13],
    mat1[4]*mat2[2]+mat1[5]*mat2[6]+mat1[6]*mat2[10]+mat1[7]*mat2[14],
    mat1[4]*mat2[3]+mat1[5]*mat2[7]+mat1[6]*mat2[11]+mat1[7]*mat2[15],
    mat1[8]*mat2[0]+mat1[9]*mat2[4]+mat1[10]*mat2[8]+mat1[11]*mat2[12],
    mat1[8]*mat2[1]+mat1[9]*mat2[5]+mat1[10]*mat2[9]+mat1[11]*mat2[13],
    mat1[8]*mat2[2]+mat1[9]*mat2[6]+mat1[10]*mat2[10]+mat1[11]*mat2[14],
    mat1[8]*mat2[3]+mat1[9]*mat2[7]+mat1[10]*mat2[11]+mat1[11]*mat2[15],
    mat1[12]*mat2[0]+mat1[13]*mat2[4]+mat1[14]*mat2[8]+mat1[15]*mat2[12],
    mat1[12]*mat2[1]+mat1[13]*mat2[5]+mat1[14]*mat2[9]+mat1[15]*mat2[13],
    mat1[12]*mat2[2]+mat1[13]*mat2[6]+mat1[14]*mat2[10]+mat1[15]*mat2[14],
    mat1[12]*mat2[3]+mat1[13]*mat2[7]+mat1[14]*mat2[11]+mat1[15]*mat2[15]
  ];
}


function randint(max_value){
  return Math.floor(Math.random()*max_value);
}

mat4.toInverseMat3 = function(a, b) {
    var c = a[0],
        d = a[1],
        e = a[2],
        g = a[4],
        f = a[5],
        h = a[6],
        i = a[8],
        j = a[9],
        k = a[10],
        l = k * f - h * j,
        o = -k * g + h * i,
        m = j * g - f * i,
        n = c * l + d * o + e * m;
    if (!n) return null;
    n = 1 / n;
    b || (b = mat3.create());
    b[0] = l * n;
    b[1] = (-k * d + e * j) * n;
    b[2] = (h * d - e * f) * n;
    b[3] = o * n;
    b[4] = (k * c - e * i) * n;
    b[5] = (-h * c + e * g) * n;
    b[6] = m * n;
    b[7] = (-j * c + d * i) * n;
    b[8] = (f * c - d * g) * n;
    return b
};


function path(cord){

  var new_cord = cord;
  new_cord[1]  += Math.sin(Math.PI*new_cord[2]/7); 
  // new_cord[0] += Math.sin(new_cord[2]/1000); 
  return new_cord;
}