code: public void set(Vector3D v1, Vector3D v2, Vector3D v3, Vector3D v4) {
          this.x1 = (float)v1.getX();
          this.y1 = (float)v1.getY();
          this.x2 = (float)v2.getX();
          this.y2 = (float)v2.getY();
          this.x3 = (float)v3.getX();
          this.y3 = (float)v3.getY();
          this.x4 = (float)v4.getX();
          this.y4 = (float)v4.getY();
          calcG();
      }
docs: Sets x,y-coordinate of corners.
  
  @param v1 The coordinates of the first corner.
  @param v2 The coordinates of the second corner.
  @param v3 The coordinates of the third corner.
  @param v4 The coordinates of the fourth corner.