BIMLoader = function(json)
{
    // 解析材质
    var materials = new Array();
    json.materials.forEach(element => {
        var material = ParseMaterial(element);
        materials.push(material);
    });

    // 解析网格
    var meshes = new Array();
    json.meshes.forEach(element => {
        var geometry = ParseGeometry(element);
        var material = materials[element.material];
        var mesh = new THREE.Mesh(geometry, material);
        meshes.push(mesh);
    });

    // 解析物体
    var scene = new THREE.Scene();

    json.instances.forEach(element => {
        var object = ParseInstance(element, meshes, element.mesh);
        scene.add(object);
    });

    return scene;

    function ParseMaterial(materialJson)
    {
        var material = new THREE.MeshPhongMaterial();

        if(materialJson.color)
            material.color.setStyle(materialJson.color);

        if(materialJson.transparent)
        {
            material.transparent = true;
            material.opacity = materialJson.transparent;
        }

        return material;
    }

    function ParseGeometry(geometryJson)
    {
        var geometry = new THREE.BufferGeometry();

        geometry.setAttribute('position', new THREE.BufferAttribute(new Float32Array(geometryJson.vertices), 3));
        
        geometry.setIndex(new THREE.BufferAttribute(new Uint32Array(geometryJson.indices), 1));

        geometry.setAttribute('normal', new THREE.BufferAttribute(new Float32Array(geometryJson.normals), 3));
        
        return geometry;
    }

    function ParseInstance(instanceJson, meshes, index)
    {
        var obj = new THREE.Object3D();

        if(instanceJson.id)
            obj.name = instanceJson.id;
        
        if(instanceJson.transform)
        {
            var matrix4 = new THREE.Matrix4();
            matrix4.fromArray(instanceJson.transform);
            obj.matrixAutoUpdate = false;
            obj.matrix.copy(matrix4);
            obj.matrixWorldNeedsUpdate = true;
        }

        if(instanceJson.visible)
            obj.visible = instanceJson.visible;

        if(instanceJson.info)
            obj.userData = instanceJson.info;

        if(Array.isArray(index))
        {
            index.forEach(element => {
                PutMesh(meshes[element], obj);
            });
        }
        else
        {
            PutMesh(meshes[index], obj);
        }

        return obj;
    }

    function PutMesh(mesh, obj)
    {
        var edges = new THREE.EdgesGeometry(mesh.geometry);
        var line = new THREE.LineSegments(edges, new THREE.LineBasicMaterial({color: 0xff0000}));
            
        obj.add(mesh);
        obj.add(line);
    }
}