[]phasorSpriter3D 无法使用

Laya.timer.frameLoop(1, this, () => {
this.phasorSpriter3D = new Laya.PhasorSpriter3D();
var _color = new Laya.Vector4(1, 0, 0, 1);
var _corners = new Array<Laya.Vector3>();
_corners[0] = new Laya.Vector3();
_corners[1] = new Laya.Vector3();
_corners[2] = new Laya.Vector3();
_corners[3] = new Laya.Vector3();
_corners[4] = new Laya.Vector3();
_corners[5] = new Laya.Vector3();
_corners[6] = new Laya.Vector3();
_corners[7] = new Laya.Vector3();
this.boxCollider.boundBox.getCorners(_corners)

this.phasorSpriter3D.begin(Laya.WebGLContext.LINES, this.camera);
this.phasorSpriter3D.line(_corners[0], _color, _corners[1], _color);
this.phasorSpriter3D.line(_corners[1], _color, _corners[2], _color);
this.phasorSpriter3D.line(_corners[2], _color, _corners[3], _color);
this.phasorSpriter3D.line(_corners[3], _color, _corners[0], _color);

this.phasorSpriter3D.line(_corners[4], _color, _corners[5], _color);
this.phasorSpriter3D.line(_corners[5], _color, _corners[6], _color);
this.phasorSpriter3D.line(_corners[6], _color, _corners[7], _color);
this.phasorSpriter3D.line(_corners[7], _color, _corners[4], _color);

this.phasorSpriter3D.line(_corners[0], _color, _corners[4], _color);
this.phasorSpriter3D.line(_corners[1], _color, _corners[5], _color);
this.phasorSpriter3D.line(_corners[2], _color, _corners[6], _color);
this.phasorSpriter3D.line(_corners[3], _color, _corners[7], _color);
this.phasorSpriter3D.end();
})