text: /**
   * 4 point bezier curve for animation/shader transitions
   * @class
   */
  export class BezierCurve{
      /**
       * @param {PIXI.Point[]} points - Array of 4 control points, default [(0,0), (0.5, 0), (0.5, 1), (1,1)]
       */
      constructor( points = [ new PIXI.Point(0.0,0.0),
                              new PIXI.Point(0.5,0.0),
                              new PIXI.Point(0.5,1.0),
                              new PIXI.Point(1.0,1.0) ] )
      {
          this.points = points
      }
      
      getY(t){
          let y = Math.pow((1.0 - t),3) * this.points[0].y;
          y += 3 * Math.pow((1.0-t),2) * t * this.points[1].y;
          y += 3 * (1.0 - t ) * Math.pow(t,2) * this.points[2].y;
          y += Math.pow(t,3) * this.points[3].y;
  
          return y;
      }
  }