在 THREE.js 中检测点击的对象 [英] Detect clicked object in THREE.js

问题描述

我有一个 THREE.js 场景，其中出现了很多元素，我需要检测用户点击了什么对象.

I have a THREE.js scene where a lot of elements appear, and I need to detect what object the user is clicking on.

到目前为止我所做的如下.相机不会移动太多 - 它只会以有限的量改变垂直位置，始终朝向同一点.我的大致方法如下:

What I have done so far is the following. The camera does not move to much - it only changes the vertical position by a limited amount, always looking towards the same point. My approximate method is the following:

• 如果点击相对于画布，我会获取坐标
• 我通过简单的重新缩放将它们转换为 webGL 场景中的水平和垂直坐标，并添加一个足够远的 Z 坐标.
• 我从上面的点开始拍摄水平光线，由 THREE.Ray() 构造
• 我使用 ray.intersectObjects() 来查找沿射线的第一个元素.

此方法大致可行，但有时与实际点相差几个像素.

This method approximately works, but it is sometimes a few pixels away from the actual point.

是否有更可靠的技术来找出用户点击的对象?

Is there a more reliable technique to find out the object where a user has clicked?

推荐答案

取决于你使用的相机类型.

1) PerspectiveCamera:是 Mr.doob 提供的链接.
2) OrthographicCamera:完全不同:

1) PerspectiveCamera: is ok link that Mr.doob provides.
2) OrthographicCamera: is quite different:

var init = function() {
  camera = new THREE.OrthographicCamera( SCREEN_WIDTH / - 2, SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, SCREEN_HEIGHT / - 2, NEAR, FAR);
  document.addEventListener( 'mousedown', onDocumentMouseDown, false );
}

function onDocumentMouseDown( e ) {
  e.preventDefault();
  var mouseVector = new THREE.Vector3();
  mouseVector.x = 2 * (e.clientX / SCREEN_WIDTH) - 1;
  mouseVector.y = 1 - 2 * ( e.clientY / SCREEN_HEIGHT );
  var raycaster = projector.pickingRay( mouseVector.clone(), camera );
  var intersects = raycaster.intersectObject( TARGET );
  for( var i = 0; i < intersects.length; i++ ) {
    var intersection = intersects[ i ],
    obj = intersection.object;
    console.log("Intersected object", obj);
  }
}

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