鼠标滚轮放大缩小问题

Question

在此处执行鼠标滚轮操作时，将鼠标滚轮移入或移出时对象前后移动。我也想知道公式的目的

            point.x = point.x * 2 - 1;
            point.y = -point.y * 2 + 1;

这里我附加了代码的功能，您可以在计算中发现错误，该错误是来回放大或缩小的，但不是正常方式

 private actionMouseWheel = (): Function => {
        const that = this;
        const cameraManager = that._cameraHandler;
        const zoomStart = new Vector2(0, 0); //center of the position
        const zoomEnd = new Vector2(0, 0); //center of the position
        const zoomSpeed = 1.015; //speed of mouse wheel
        const zoomFactor = 2.015;
        let w;
        let xy = new Vector2();
        let dist = 0;
        let detail = {};
        let closestPoint = new Vector3();
        closestPoint = cameraManager.Target;

        const dispatchEvent = () => {
            that._orbitController.trigger('zoom', {
                type: 'zoom',
                detail: detail
            });
        };

        const interval = 15;
        let marker = true,
            counter1 = 0,
            counter2;
        function wheelStart() {
            marker = false;
            that._layerHandler.isFrustumCulled = true;
            dispatchEvent();
            wheelAct();
        }
        function wheelAct() {
            counter2 = counter1;
        }
        function wheelEnd() {
            marker = true,
                counter1 = 0,
                counter2 = 0;
            that._layerHandler.isFrustumCulled = false;
            that.render();
        }
        let pPoint = null;
        const callback = (resp) => {
            objCallback(xy, resp);
        };
        const objCallback = (point, id) => {
            point.x = point.x * 2 - 1;
            point.y = -point.y * 2 + 1;
            pPoint = null;

            const obj = that._pickingHandler.getPickingDataById(id);
            if (obj) {
                pPoint = that.updatePivotOrbitPoint(point, obj);
            }
            update(point);
            console.log("point on mouse wheel");
            console.log(point);
        };
        const update = (point) => {
            const dd = 1000; // 3048 * 0.5; // 3048mm = 10ft
            const ddd = 1000;
            if (pPoint !== null) {
                closestPoint = pPoint;
                dist = cameraManager.Eye.distanceTo(pPoint);
            }
            else {
                dist = cameraManager.Eye.distanceTo(closestPoint) > cameraManager.Dist ? cameraManager.Dist : cameraManager.Eye.distanceTo(closestPoint);
            }

            dist = dist < dd ? dd : dist;
            dist = Math.ceil(dist / (0.1 * 100));
            const _factor = dd + (dist + (zoomEnd.y - zoomStart.y)) * zoomSpeed;
            detail = {
                x: point.x,
                y: point.y,
                d: w.f,
                factor: _factor,
                callback: () => { }
            };
            wheelStart();
        };

        return ((e): void => {
            w = e.detail;
            if (!w) { return; }
            zoomEnd.copy(zoomStart);
            zoomStart.y -= w.f * 0.00025;
            xy = that.getMouseOnScreen(w.x, w.y);
            that.validatePickingIntersection(that.get2dMouseOnScreen(w.x, w.y), callback);
            zoomStart.copy(zoomEnd);
        });
    }