如何使用三个 JS 动画 Camera.lookAt [英] How To Animate Camera.lookAt using Three JS

问题描述

我有一个场景，它渲染了一个包含多个对象的板.单击其中一个对象并通过使用对象拾取，我可以获取对象并设置摄像机位置的动画以使其位于对象的头顶"视图中.然后使用camera.lookAt方法我可以强制相机直接看对象.

I have a scene which renders a board with several objects. Clicking on one of the objects and by use of object picking I can get the object and animate the cameras position to sit in an 'overhead' view of the object. Then using the camera.lookAt method I can force the camera to look directly at the object.

在 onUpdate 方法中调用 camera.lookAt 时，我注意到动画开始时的快速跳转，因为它最初有很大的旋转距离以查看所选对象.相比之下，对 camera.lookAt 的每次后续调用都很小，而且动画效果很好.

I am noticing a quick jump at the start of my animation when calling camera.lookAt within the onUpdate method as it initially has a large distance to rotate to look at the object selected. Each subsequent call to camera.lookAt is tiny in comparison and is animated nicely.

// Position the camera to fit
var tween = new TWEEN.Tween(camera.position).to({
    x: selectedObject.position.x,
    y: selectedObject.position.y,
    z: 1
}).easing(TWEEN.Easing.Quadratic.InOut).onUpdate(function() {
    camera.lookAt(selectedObject.position);
}).onComplete(function() {
    camera.lookAt(selectedObject.position);
}).start();

有什么方法可以为该方法设置动画，还是我必须手动转换相机的矩阵值才能查看我选择的对象?

Is there any way to animate the method or will I have to manually transform the matrix values of the camera to look at my selected object?

这是一个带有示例的小提琴.它使用 WebGLRenderer，因此请使用合适的浏览器.

Here is a fiddle with an example. It uses WebGLRenderer so please use a suitable browser.

http://jsfiddle.net/fungus1487/SMLwa/

感谢您的帮助.

推荐答案

您可以做的一件事是在相机位置和相机目标(您必须定义)之间进行调整.

One thing you can do is tween both the camera position and the camera target (which you have to define).

var tween = new TWEEN.Tween( camera.position )
    .to( {
        x: selectedObject.position.x,
        y: selectedObject.position.y,
        z: 1
    } )
    .easing( TWEEN.Easing.Linear.None ).onUpdate( function () {

        camera.lookAt( camera.target );

    } )
    .onComplete( function () {

        camera.lookAt( selectedObject.position );

    } )
    .start();

var tween = new TWEEN.Tween( camera.target )
    .to( {
        x: selectedObject.position.x,
        y: selectedObject.position.y,
        z: 0
    } )
    .easing( TWEEN.Easing.Linear.None )
    .onUpdate( function () {

    } )
    .onComplete( function () {

        camera.lookAt( selectedObject.position );

    } )
    .start();

这有点棘手，因为补间需要完全同时运行，而它们不...这就是在第二个补间中调用 camera.lookAt() 的原因.

It's a little tricky, because the tween's need to run exactly concurrently, and they don't... This is the reason for the camera.lookAt() call in the second tween.

这篇关于如何使用三个 JS 动画 Camera.lookAt的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！