face.js

var Point = require('./point');

var _faceCount = 0;

var Face = function(point1, point2, point3, register){
    this.id = _faceCount++;

    if(register == undefined){
        register = true;
    }

    this.points = [
        point1,
        point2,
        point3
        ];
    if(register){
        point1.registerFace(this);
        point2.registerFace(this);
        point3.registerFace(this);
    }
};

Face.prototype.getOtherPoints = function(point1){
    var other = [];
    for(var i = 0; i < this.points.length; i++){
        if(this.points[i].toString() !== point1.toString()){
            other.push(this.points[i]);
        }
    }
    return other;
}

Face.prototype.findThirdPoint = function(point1, point2){
    for(var i = 0; i < this.points.length; i++){
        if(this.points[i].toString() !== point1.toString() && this.points[i].toString() !== point2.toString()){
            return this.points[i];
        }
    }
}

Face.prototype.isAdjacentTo = function(face2){
    // adjacent if 2 of the points are the same
    
    var count = 0;
    for(var i = 0; i< this.points.length; i++){
        for(var j =0 ; j< face2.points.length; j++){
            if(this.points[i].toString() == face2.points[j].toString()){
                count++;
                
            }
        }
    }

    return (count == 2);
}

Face.prototype.getCentroid = function(clear){
    if(this.centroid && !clear){
        return this.centroid;
    }

    var x = (this.points[0].x + this.points[1].x + this.points[2].x)/3;
    var y = (this.points[0].y + this.points[1].y + this.points[2].y)/3;
    var z = (this.points[0].z + this.points[1].z + this.points[2].z)/3;

    var centroid = new Point(x,y,z);

    this.centroid = centroid;

    return centroid;

}

module.exports = Face;