three.js 加载一个3D模型 做一个测量距离和面积的功能，距离测量结果用2像素的线段表示，面积用多边形表示，结果文字用sprite展示，线段需要有辉光效果

以下是示例代码，用于加载3D模型并添加测量距离和面积的功能，以及添加辉光效果和结果文字：

// 加载模型
const loader = new THREE.GLTFLoader();
loader.load('model.gltf', function(gltf) {
  scene.add(gltf.scene);

  // 添加测量距离功能
  const measureLine = new THREE.LineSegments(
    new THREE.BufferGeometry().setFromPoints([new THREE.Vector3(), new THREE.Vector3()]),
    new THREE.LineBasicMaterial({ color: 0xffffff, linewidth: 2 })
  );
  scene.add(measureLine);

  // 添加测量面积功能
  const measureArea = new THREE.Mesh(
    new THREE.BufferGeometry(),
    new THREE.MeshBasicMaterial({ color: 0xffffff, side: THREE.DoubleSide, transparent: true, opacity: 0.5 })
  );
  scene.add(measureArea);

  // 添加结果文字
  const measureText = new THREE.Sprite(new THREE.SpriteMaterial({ color: 0xffffff }));
  scene.add(measureText);

  // 添加辉光效果
  const glower = new THREE.Mesh(
    new THREE.BufferGeometry(),
    new THREE.MeshBasicMaterial({ color: 0xffffff, side: THREE.BackSide, blending: THREE.AdditiveBlending })
  );
  glower.scale.set(1.2, 1.2, 1.2);
  scene.add(glower);

  // 监听鼠标事件
  const raycaster = new THREE.Raycaster();
  const mouse = new THREE.Vector2();
  let startPoint = null;
  let endPoint = null;
  let polygonPoints = [];
  let distance = null;
  let area = null;

  function onMouseDown(event) {
    event.preventDefault();

    mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
    mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;

    raycaster.setFromCamera(mouse, camera);

    const intersects = raycaster.intersectObjects(scene.children, true);

    if (intersects.length > 0) {
      const point = intersects[0].point;

      if (startPoint === null) {
        startPoint = point.clone();
        polygonPoints.push(point.clone());
      } else if (endPoint === null) {
        endPoint = point.clone();
        measureLine.geometry.setFromPoints([startPoint, endPoint]);
        measureLine.visible = true;
        distance = startPoint.distanceTo(endPoint);
        measureText.position.copy(endPoint);
        measureText.material.visible = true;
        measureText.material.map = createTextTexture(distance.toFixed(2));
        glower.geometry = createGlowGeometry(measureLine.geometry);
        glower.visible = true;
      } else {
        polygonPoints.push(point.clone());
        const polygon = new THREE.Shape(polygonPoints);
        const geometry = new THREE.ShapeBufferGeometry(polygon);
        measureArea.geometry.dispose();
        measureArea.geometry = geometry;
        measureArea.visible = true;
        area = THREE.ShapeUtils.area(polygonPoints);
        measureText.position.copy(endPoint);
        measureText.material.visible = true;
        measureText.material.map = createTextTexture(area.toFixed(2));
        glower.geometry = createGlowGeometry(measureArea.geometry);
        glower.visible = true;

        startPoint = null;
        endPoint = null;
        polygonPoints = [];
      }
    }
  }

  function onMouseMove(event) {
    event.preventDefault();

    mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
    mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;

    raycaster.setFromCamera(mouse, camera);

    if (startPoint !== null && endPoint === null) {
      const intersects = raycaster.intersectObjects(scene.children, true);

      if (intersects.length > 0) {
        endPoint = intersects[0].point.clone();
        measureLine.geometry.setFromPoints([startPoint, endPoint]);
      }
    }
  }

  function onMouseUp(event) {
    event.preventDefault();
  }

  function createTextTexture(text) {
    const canvas = document.createElement('canvas');
    canvas.width = 256;
    canvas.height = 256;
    const context = canvas.getContext('2d');
    context.font = '40px Arial';
    context.fillStyle = '#ffffff';
    context.textAlign = 'center';
    context.fillText(text, canvas.width / 2, canvas.height / 2);

    const texture = new THREE.CanvasTexture(canvas);
    texture.needsUpdate = true;
    texture.minFilter = THREE.LinearFilter;
    texture.magFilter = THREE.LinearFilter;

    return texture;
  }

  function createGlowGeometry(geometry) {
    const positions = geometry.attributes.position.array;
    const count = positions.length / 3;
    const offsets = new Float32Array(count * 3);
    const colors = new Float32Array(count * 3);
    const color = new THREE.Color(0xffffff);
    const glowColor = new THREE.Color(0x00ffff);
    const size = 1.2;

    for (let i = 0; i < count; i++) {
      const index = i * 3;
      const x = positions[index];
      const y = positions[index + 1];
      const z = positions[index + 2];
      offsets[index] = x;
      offsets[index + 1] = y;
      offsets[index + 2] = z;
      color.toArray(colors, index);
      glowColor.toArray(colors, index + 3);
    }

    const glowGeometry = new THREE.BufferGeometry();
    glowGeometry.setAttribute('position', new THREE.BufferAttribute(offsets, 3));
    glowGeometry.setAttribute('color', new THREE.BufferAttribute(colors, 3));
    glowGeometry.computeBoundingSphere();

    return glowGeometry;
  }

  window.addEventListener('mousedown', onMouseDown);
  window.addEventListener('mousemove', onMouseMove);
  window.addEventListener('mouseup', onMouseUp);
});