, 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
                ...nny, ...nny, ...nny, ...nny,
                // 后 +y
                ...npy, ...npy, ...npy, ...npy,
                // 左 -x
                ...nnx, ...nnx, ...nnx, ...nnx,
                // 右 +x
                ...npx, 