如何在THREE.js中绘制从3D到2D的线段？

// 创建场景
var scene = new THREE.Scene();

// 创建相机
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.z = 5;

// 创建渲染器
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

// 创建几何体
var geometry = new THREE.BufferGeometry();
var positions = new Float32Array([
    0, 0, 0,  // 起点坐标
    1, 1, 1   // 终点坐标
]);
geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));

// 创建材质
var material = new THREE.LineBasicMaterial({ color: 0x00ff00 });

// 创建线段对象
var line = new THREE.Line(geometry, material);

// 将线段对象添加到场景中
scene.add(line);

// 渲染循环
function animate() {
    requestAnimationFrame(animate);
    renderer.render(scene, camera);
}
animate();