rotate uv 90 degs for front and left

voxel-mesh.js

Mesh.prototype.faceVertexUv = function(i) {
  var vs = [
    this.meshed.vertices[i*4+0],
    this.meshed.vertices[i*4+1],
    this.meshed.vertices[i*4+2],
    this.meshed.vertices[i*4+3]
  ]
  var spans = {
    x0: vs[0][0] - vs[1][0],
    x1: vs[1][0] - vs[2][0],
    y0: vs[0][1] - vs[1][1],
    y1: vs[1][1] - vs[2][1],
    z0: vs[0][2] - vs[1][2],
    z1: vs[1][2] - vs[2][2]
  }
  var size = {
    x: Math.max(Math.abs(spans.x0), Math.abs(spans.x1)),
    y: Math.max(Math.abs(spans.y0), Math.abs(spans.y1)),
    z: Math.max(Math.abs(spans.z0), Math.abs(spans.z1))
  }
  if (size.x === 0) {
    if (spans.y0 > spans.y1) {
      // left
      var width = size.y
      var height = size.z
    }
    else {
      var width = size.z
      var height = size.y
    }
  }
  if (size.y === 0) {
    if (spans.x0 > spans.x1) {
      var width = size.x
      var height = size.z
    }
    else {
      var width = size.z
      var height = size.x
    }
  }
  if (size.z === 0) {
    if (spans.x0 > spans.x1) {
      var width = size.x
      var height = size.y
    }
    else {
      // front
      var width = size.y
      var height = size.x
    }
  }
  if ((size.z === 0 && spans.x0 < spans.x1) || (size.x === 0 && spans.y0 > spans.y1)) {
    return [
      new THREE.Vector2(width, 0),
      new THREE.Vector2(0, 0),
      new THREE.Vector2(0, height),
      new THREE.Vector2(width, height)
    ]
  } else {
    return [
      new THREE.Vector2(0, 0),
      new THREE.Vector2(0, height),
      new THREE.Vector2(width, height),
      new THREE.Vector2(width, 0)
    ]
  }
}