ComputerGraphics/20210129/demo/js/main.js

// 场景、相机、光源定义定义
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000000);
camera.up.set(0,0,1);
var light = new THREE.AmbientLight(0xffffff);
scene.add(light);

// 渲染器定义
var canvas = document.createElement( 'canvas' );
canvas.id = 'model';
var context = canvas.getContext( 'webgl2', {antialias: true, preserveDrawingBuffer: true});
var renderer = new THREE.WebGLRenderer({canvas: canvas, context: context, logarithmicDepthBuffer: true});
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setClearColor(0xffffff);
document.body.appendChild(renderer.domElement);

window.addEventListener('resize', onWindowResize);

// 相机控制
var controls = new THREE.OrbitControls(camera, renderer.domElement);

// 加载模型数据
const loader = new THREE.FileLoader();
loader.load(
    '/demo/res/single-demo.json',
    function(data)
    {
        var bimScene = BIMLoader(JSON.parse(data));
        var box = new THREE.Box3();
        box.expandByObject(bimScene);
        var center = new THREE.Vector3();
        box.getCenter(center);
        var size = new THREE.Vector3();
        box.getSize(size);
        var result = size.x > size.y ? size.x : size.y;
        result = result > size.z ? result : size.z;
        var maxLength =  Math.round(result);
        var radius = center.distanceTo(new THREE.Vector3(center.x + (maxLength/2), center.y + (maxLength/2), center.z + (maxLength/2)));
        var cameraPos = new THREE.Vector3(center.x + radius * Math.cos(Math.PI/18) * Math.cos(Math.PI/4), center.y - radius * Math.cos(Math.PI/18) * Math.sin(Math.PI/4), center.z + radius * Math.sin(Math.PI/18));
        camera.position.copy(cameraPos);
        controls.target = box.getCenter();
        scene.add(bimScene);
    },
    function(xhr)
    {
        console.log((xhr.loaded / xhr.total * 100) + '% loaded');   
    },
    function(err)
    {
        console.error('An error happened');
    }
);

function onWindowResize()
{
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();

    renderer.setSize(window.innerWidth, window.innerHeight);
}

function animate() {
    requestAnimationFrame( animate );
    controls.update();
    renderer.render( scene, camera );
}

 animate();