使用cc.RenderTexture动态创建贴图并显示，但会一直有上一帧的残留，用cc.Graphics能用clear()清理掉，但不知道这个该如何处理了
@ccclass
export default class newClass extends cc.Component {
@property({
type: cc.Texture2D
})
tex: cc.Texture2D = null;
public start (): void {
this.render = new cc.RenderTexture();
}
public update (dt: number): void {
let gl = cc.game._renderContext;
this.render.initWithSize(600, 600, gl.STENCIL_INDEX8);
this.render.drawTextureAt(this.tex, 0, 0);
if(!this.sprite.spriteFrame) {
this.sprite.spriteFrame = new cc.SpriteFrame(this.render, cc.rect(0,0,600,600));
}
}
}
