remove access to bpy.context in filesaver code (LuxCoreRender#221)

doc/project_structure.md

@@ -38,8 +38,8 @@ It's also responsible for scene and session updates during viewport render sessi
 Note: If we have a context (i.e. `context is not None`) then we are in viewport render mode. 
 If we have no context (`context is None`) then we are in final render or material preview mode.
 This is not explained/commented all the time in the code because it's such a fundamental concept.
-However, it's not like we have no context at all in final render mode, you can still get it with `bpy.context`. 
-But it is not passed into the methods by the RenderEngine API in Blender.
+Important: It is forbidden by the Blender API to access the context during final render, so you 
+should not resort to hacks like using `bpy.context` when there is no context passed into a function.
 
 Note also that nodes are not exported here, they have their own 
 export methods in their classes (in the **nodes** directory, see below).

export/config.py

@@ -247,7 +247,7 @@ def _convert_filesaver(scene, definitions, luxcore_engine):
     filesaver_path = config.filesaver_path
     output_path = utils.get_abspath(filesaver_path, must_exist=True, must_be_existing_dir=True)
 
-    blend_name = bpy.path.basename(bpy.context.blend_data.filepath)
+    blend_name = bpy.path.basename(bpy.data.filepath)
     blend_name = os.path.splitext(blend_name)[0]  # remove ".blend"
 
     if not blend_name: