texture map list validation

Summary: Add some more validation of a list of texture maps. Move the initialisation of maps_padded to a new function to reduce complexity.

Reviewed By: nikhilaravi

Differential Revision: D29263443

fbshipit-source-id: 153e262d2e9af21090570768020fca019e364024

pytorch3d/renderer/mesh/textures.py

@@ -707,30 +707,42 @@ class TexturesUV(TexturesBase):
         else:
             raise ValueError("Expected verts_uvs to be a tensor or list")
 
+        if isinstance(maps, (list, tuple)):
+            self._maps_list = maps
+        else:
+            self._maps_list = None
+        self._maps_padded = self._format_maps_padded(maps)
+
+        if self._maps_padded.device != self.device:
+            raise ValueError("maps must be on the same device as verts/faces uvs.")
+
+        self.valid = torch.ones((self._N,), dtype=torch.bool, device=self.device)
+
+    def _format_maps_padded(
+        self, maps: Union[torch.Tensor, List[torch.Tensor]]
+    ) -> torch.Tensor:
         if isinstance(maps, torch.Tensor):
             if maps.ndim != 4 or maps.shape[0] != self._N:
                 msg = "Expected maps to be of shape (N, H, W, C); got %r"
                 raise ValueError(msg % repr(maps.shape))
-            self._maps_padded = maps
-            self._maps_list = None
-        elif isinstance(maps, (list, tuple)):
+            return maps
+
+        if isinstance(maps, (list, tuple)):
             if len(maps) != self._N:
                 raise ValueError("Expected one texture map per mesh in the batch.")
-            self._maps_list = maps
             if self._N > 0:
-                maps = _pad_texture_maps(maps, align_corners=self.align_corners)
+                if not all(map.ndim == 3 for map in maps):
+                    raise ValueError("Invalid number of dimensions in texture maps")
+                if not all(map.shape[2] == maps[0].shape[2] for map in maps):
+                    raise ValueError("Inconsistent number of channels in maps")
+                maps_padded = _pad_texture_maps(maps, align_corners=self.align_corners)
             else:
-                maps = torch.empty(
+                maps_padded = torch.empty(
                     (self._N, 0, 0, 3), dtype=torch.float32, device=self.device
                 )
-            self._maps_padded = maps
-        else:
-            raise ValueError("Expected maps to be a tensor or list.")
+            return maps_padded
 
-        if self._maps_padded.device != self.device:
-            raise ValueError("maps must be on the same device as verts/faces uvs.")
-
-        self.valid = torch.ones((self._N,), dtype=torch.bool, device=self.device)
+        raise ValueError("Expected maps to be a tensor or list of tensors.")
 
     def clone(self) -> "TexturesUV":
         tex = self.__class__(