         var positions = new Float64Array(boxVertex);
                // 2 定义法向数组
                var npx = [1, 0, 0];
                var nnx = [-1, 0, 0];
                var npy = [0, 1, 0];
                var nny = [0, -1, 0];
                var npz = [0, 0, 1];
                var nnz = [0, 0, -1];
                var normals = new Float32Array([
                    // 下 -z
                    ...nnz, ...nnz, ...nnz, ...nnz,
                    // 前 -y
                    