project.js

function vec3(xx, yy, zz) {
    this.x = xx || 0;
    this.y = yy || 0;
    this.z = zz || 0;
    this.translate = function (d) { return new vec3(this.x+d[0], this.y+d[1],this.z+d[2]) }
    this.scale = function(s) { return new vec3(s*this.x, s*this.y,s*this.z) }
    this.rotz = function(ang) {
      var c = Math.cos(ang)
      var s = Math.sin(ang)
      return new vec3(this.x*c - this.y*s,this.y*c + this.x*s, this.z)
    }
    this.rotx = function(ang) {
      var c = Math.cos(ang)
      var s = Math.sin(ang)
      return new vec3(this.x,this.y*c - this.z*s, this.z*c + this.y*s);
    }
    this.proj = function (perspective) {
        return new vec3(
          this.x * ( perspective/ ( perspective + this.z ) ),
          this.y * ( perspective/ ( perspective + this.z ) ),
          1
        );
    }
}

/*
 * Transform 2d pixel pos of a css3d transformed div
 */

function transform3d(pos, w, h) {
  var v = new vec3(pos.x,  pos.y, 0);
  v = v
    .translate([-w/2.0, -h/2.0, -50.0])
    .rotx(45*Math.PI/180.0)
    .proj(1000)
    .translate([w/2.0, h/2.0, 0.0])
  return {
    x: v.x,
    y: v.y
  }
}

function latlonTo3DPixel(map, latlon) {
  var pos = map.latLngToContainerPoint(latlon);
  var s = map.getSize()
  return transform3d(pos, s.x, s.y);
}