JavaScript加载导出MIF文件的示例详解

// 假设你有一个MIF文件的内容作为字符串
const mifContent = `
VERSION 300
Charset "WindowsLatin1"
Delimiter ","
CoordSys Earth Projection 1, 104
Columns 2
  ID Integer
  NAME Char(25)
Data
Point
  10.0 20.0
`;

// 解析MIF内容
function parseMIF(content) {
    const lines = content.split('\n').map(line => line.trim()).filter(line => line.length > 0);
    let i = 0;
    let vertices = [];
    let attributes = [];

    while (i < lines.length) {
        if (lines[i].startsWith('Point')) {
            i++;
            const coords = lines[i].split(' ').map(Number);
            vertices.push(new THREE.Vector3(coords[0], coords[1], 0));
        }
        // 处理其他几何类型（Line, Region, Text）...
        i++;
    }

    return { vertices, attributes };
}

// 创建three.js几何体
function createGeometryFromMIF(mifData) {
    const geometry = new THREE.BufferGeometry();
    const positions = [];

    mifData.vertices.forEach(vertex => {
        positions.push(vertex.x, vertex.y, vertex.z);
    });

    geometry.setAttribute('position', new THREE.Float32BufferAttribute(positions, 3));

    return geometry;
}

// 使用示例
const mifData = parseMIF(mifContent);
const geometry = createGeometryFromMIF(mifData);

const material = new THREE.PointsMaterial({ color: 0xff0000 });
const points = new THREE.Points(geometry, material);

scene.add(points);

// 假设你有一个three.js的几何体和属性数据
const geometry = new THREE.BufferGeometry().setFromPoints([
    new THREE.Vector3(10, 20, 0),
    new THREE.Vector3(30, 40, 0),
    // 添加更多点...
]);

const attributes = [
    { ID: 1, NAME: 'Point1' },
    { ID: 2, NAME: 'Point2' },
    // 添加更多属性...
];

// 生成MIF内容
function generateMIFContent(vertices, attributes) {
    let mifContent = `VERSION 300\n`;
    mifContent += `Charset "WindowsLatin1"\n`;
    mifContent += `Delimiter ","\n`;
    mifContent += `CoordSys Earth Projection 1, 104\n`;
    mifContent += `Columns 2\n`;
    mifContent += `  ID Integer\n`;
    mifContent += `  NAME Char(25)\n`;
    mifContent += `Data\n`;

    vertices.forEach((vertex, index) => {
        mifContent += `Point\n`;
        mifContent += `${vertex.x} ${vertex.y}\n`;
    });

    // 生成MID内容
    let midContent = '';
    attributes.forEach(attr => {
        midContent += `${attr.ID},${attr.NAME}\n`;
    });

    return { mifContent, midContent };
}

// 使用示例
const { mifContent, midContent } = generateMIFContent(
    Array.from(geometry.attributes.position.array).reduce((points, value, index, array) => {
        if (index % 3 === 0) points.push(new THREE.Vector3(array[index], array[index + 1], array[index + 2]));
        return points;
    }, []),
    attributes
);

// 创建下载链接
function downloadFile(filename, content) {
    const blob = new Blob([content], { type: 'text/plain' });
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = filename;
    link.click();
}

// 导出MIF和MID文件
downloadFile('exported_model.mif', mifContent);
downloadFile('exported_model.mid', midContent);