问在文档中切换v7锻造中的可查看图形？

EN

var viewer;
var viewables;
var indexGeom;
var viewdoc;

//Call back for viewer DocumentLoadSuccess 
function onDocumentLoadSuccess(doc) {
    viewdoc = doc;
    
    indexGeom = 0;
    viewables = doc.getRoot().search({ 'type': 'geometry' });
    viewer.loadDocumentNode(doc, viewables[indexGeom]).then(i => {
        activateUI();
     });
}

//Call back for switch to next view button
function loadNextModel() {
    // Next geometry index. Loop back to 0 when overflown.
    indexGeom = (indexGeom + 1) % viewables.length;
    
    viewer.tearDown();
    
    viewer.loadDocumentNode(viewdoc, viewables[indexGeom]).then(i => {
        activateUI();
    });
}