src/utils/data3d/buffer/triangulate-2d.js
function orient (data, p, q, r) {
  var o = (data[q + 1] - data[p + 1]) * (data[r] - data[q]) - (data[q] - data[p]) * (data[r + 1] - data[q + 1])
  return o > 0 ? 1 : o < 0 ? -1 : 0
}
function orient (data, p, q, r) {
  var o = (data[q + 1] - data[p + 1]) * (data[r] - data[q]) - (data[q] - data[p]) * (data[r + 1] - data[q + 1])
  return o > 0 ? 1 : o < 0 ? -1 : 0
}
function orient ( data , p , q , r ) { var o = ( data [ q + 1 ] - data [ p + 1 ] ) * ( data [ r ] - data [ q ] ) - ( data [ q ] - data [ p ] ) * ( data [ r + 1 ] - data [ q + 1 ] ) return o > 0 ? 1 : o < 0 ? - 1 : 0 }
winding order of triangle formed by 3 given points
winding order of triangle formed by 3 given points