void MaterialXMLExportDialog::exportMaterials()
{
    selectedMaterials_.clear();

    for (int row=0;row<materialView_->rowCount();++row) {
        MaterialTableItem* item = static_cast<MaterialTableItem*>(materialView_->item(row, 0));
        if (item->checkState()!=Qt::Checked) continue;
        selectedMaterials_.push_back(item->getMaterial());
    }

    accept();
}