三.js raycaster 交集

我编写了下面的代码来获取与 3d 形状的交点。它工作得很好，但如果有两个与形状的交点，它只返回最远的交点，而我需要与形状最近的交点。我怎样才能到达最近的十字路口？

  /*here I create a cube*/

            var geometry0 = new THREE.Geometry()
            geometry0.vertices = [new THREE.Vector3(0.5, -0.5, 0.5), new THREE.Vector3(-0.5, -0.5, 0.5), new THREE.Vector3(-0.5, -0.5, -0.5), new THREE.Vector3(0.5, -0.5, -0.5), new THREE.Vector3(0.5, 0.5, 0.5), new THREE.Vector3(-0.5, 0.5, 0.5), new THREE.Vector3(-0.5, 0.5, -0.5), new THREE.Vector3(0.5, 0.5, -0.5)];
            geometry0.faces = [new THREE.Face3(3, 2, 1), new THREE.Face3(3, 1, 0), new THREE.Face3(4, 5, 6), new THREE.Face3(4, 6, 7), new THREE.Face3(0, 1, 5), new THREE.Face3(0, 5, 4), new THREE.Face3(1, 2, 6), new THREE.Face3(1, 6, 5), new THREE.Face3(2, 3, 7), new THREE.Face3(2, 7, 6), new THREE.Face3(3, 0, 4), new THREE.Face3(3, 4, 7)];
            geometry0.computeFaceNormals();
            geometry0.computeVertexNormals();
            var material0 = new THREE.MeshBasicMaterial({color: 0x39d2dbe7fff39d2, transparent: true, opacity: 0});
            mesh0 = new THREE.Mesh(geometry0, material0);
            egh0 = new THREE.EdgesHelper(mesh0, 0x000);
            egh0.material.linewidth = 2;
            scene.add(egh0);


            objects.push(mesh0);
            projector = new THREE.Projector();
            console.log(objects);
            mouse2D = new THREE.Vector3(0, 10000, 0.5);//controllare i valori



    /* here I create the ray */


document.addEventListener('click', onDocumentMouseClick, false);


        function onDocumentMouseClick(event) {

            event.preventDefault();

            mouse2D.x = (event.clientX / window.innerWidth) * 2 - 1;
            mouse2D.y = -(event.clientY / window.innerHeight) * 2 + 1;
             var vector = new THREE.Vector3( mouse2D.x, mouse2D.y, 0.5 );

            projector.unprojectVector( vector, camera );

            var raycaster = new THREE.Raycaster( camera.position, vector.sub( camera.position ).normalize() );


            var intersects = raycaster.intersectObjects( objects );

            if (intersects.length > 0) {
                console.log("ok");} 

如果我检查 intersects[0].point 我只能看到立方体相交的最远点面而不是第一个面（例如，如果您看着前面的立方体并制作一条射线，则该射线在与第一个面相交之前并与第一个面后面的第二个面相交。） 此代码的目标是仅在单击顶点时创建事件。 所以在此之后我编写了代码来计算点击点和所有顶点的欧几里德距离 并返回距离单击点最近的顶点。 如果您有其他想法仅在单击顶点时触发事件，我们欢迎。

是的，基本思想是ray casting就是我们投影一条垂直于平面的射线，我们找出该射线相交的对象列表。

因此，要访问第一个元素，您所要做的就是添加以下代码。

var intersects = raycaster.intersectObjects(objects);

if (intersects.length > 0) {
       var firstIntersectedObject  = intersects[0];
       // this will give you the first intersected Object if there are multiple.
    }

Here is 我的另一篇帖子 https://stackoverflow.com/questions/24690731/three-js-3d-models-as-hyperlink/24692057#24692057我在其中以更详细的方式解释了一些内容，您可以参考它以更好地理解光线投射的功能。