code: def _interpolate_zbuf(
      pix_to_face: torch.Tensor,
      barycentric_coords: torch.Tensor,
      meshes,
  ) -> torch.Tensor:
      """
      A helper function to calculate the z buffer for each pixel in the
      rasterized output.
  
      Args:
          pix_to_face: LongTensor of shape (N, H, W, K) specifying the indices
              of the faces (in the packed representation) which
              overlap each pixel in the image.
          barycentric_coords: FloatTensor of shape (N, H, W, K, 3) specifying
              the barycentric coordinates of each pixel
              relative to the faces (in the packed
              representation) which overlap the pixel.
          meshes: Meshes object representing a batch of meshes.
  
      Returns:
          zbuffer: (N, H, W, K) FloatTensor
      """
      verts = meshes.verts_packed()
      faces = meshes.faces_packed()
      faces_verts_z = verts[faces][..., 2][..., None]  # (F, 3, 1)
      zbuf = interpolate_face_attributes(
          pix_to_face, barycentric_coords, faces_verts_z
      )[
          ..., 0
      ]  # (1, H, W, K)
      zbuf[pix_to_face == -1] = -1
      return zbuf
  
file_path: pytorch3d/pytorch3d/renderer/mesh/utils.py
imports: from typing import List, NamedTuple, Tuple
  import torch
  from pytorch3d.ops import interpolate_face_attributes
label_desc: Use image node_id 2 for calling a global function with example usage: _interpolate_zbuf(pix_to_face, barycentric_coords, meshes) and returns: zbuf