_shouldDrawCheck() {
        // get plane bounding rect
        const actualPlaneBounds = this._getWebGLDrawRect();

        // if we decide to draw the plane only when visible inside the canvas
        // we got to check if its actually inside the canvas
        if(
            Math.round(actualPlaneBounds.right) <= this.renderer._boundingRect.left
            || Math.round(actualPlaneBounds.left) >= this.renderer._boundingRect.left + this.renderer._boundingRect.width
            || Math.round(actualPlaneBounds.bottom) <= this.renderer._boundingRect.top
            || Math.round(actualPlaneBounds.top) >= this.renderer._boundingRect.top + this.renderer._boundingRect.height
        ) {
            if(this._shouldDraw) {
                this._shouldDraw = false;
                // callback for leaving view
                this.renderer.nextRender.add(() => this._onLeaveViewCallback && this._onLeaveViewCallback());
            }
        }
        else {
            if(!this._shouldDraw) {
                // callback for entering view
                this.renderer.nextRender.add(() => this._onReEnterViewCallback && this._onReEnterViewCallback());
            }
            this._shouldDraw = true;
        }
    }
This function checks if the plane is currently visible in the canvas and sets _shouldDraw property according to this test
     This is our real frustum culling check
*