Set data path to launch viewer for DreamFusion (#1776)

* Set data path to launch viewer for DreamFusion

* Apply formatter

* Fallback to 'base_dir' if data manager has no path

* Make if statement non-inline

* Reformat

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Co-authored-by: Matthew Tancik <mattt4001@gmail.com>

scripts/viewer/run_viewer.py

@@ -61,8 +61,15 @@ class RunViewer:
     def _start_viewer(self, config: TrainerConfig, pipeline: Pipeline):
         base_dir = config.get_base_dir()
         viewer_log_path = base_dir / config.viewer.relative_log_filename
+
+        datapath = pipeline.datamanager.get_datapath()
+        if datapath is None:
+            datapath = base_dir
+
         viewer_state, banner_messages = viewer_utils.setup_viewer(
-            config.viewer, log_filename=viewer_log_path, datapath=pipeline.datamanager.get_datapath()
+            config.viewer,
+            log_filename=viewer_log_path,
+            datapath=datapath,
         )
 
         # We don't need logging, but writer.GLOBAL_BUFFER needs to be populated