Java LibGdx，viewport/camera#unproject有时（不总是）返回错误的值

我使用正交摄影机和取消投影功能将屏幕点转换为世界点

一切正常，但有时#unproject方法返回一些几乎不错/预期的值，但几乎，所以您可以看到屏幕/世界跳跃X像素/单位

//screenX, screenY -> mouse position when wheel is scrolled

(...) <- calculate new world size because of zooming and set it up in viewport object

//calculate difference in world two points
//where mouse was before zooming and where mouse is after it,
//related to worldCoords, and apply it to camera:
Vector2 before = viewport.unproject(new Vector2(screenX, screenY));
camera.viewportWidth = viewport.getWorldWidth();
camera.viewportHeight = viewport.getWorldHeight();
camera.update();
Vector2 after = viewport.unproject(new Vector2(screenX, screenY));
camera.position.x -= after.x - before.x;
camera.position.y -= after.y - before.y;

看起来这条线是有罪的：

view.setToLookAt(position, tmp.set(position).add(direction), up);

您可以复制此方法的代码并创建自己的代码，而不需要它。我想这个方法只是一个小问题，很难找到答案。现在，其他人必须更深入，找到setToLookAt内部的真正原因

view.setToLookAt(position, tmp.set(position).add(direction), up);