fix(cnn_v3): blender_export Blender 5 compositor activation + document RenderLayer sockets

- Activate compositor in Blender 5.0+ by relying on compositing_node_group
  assignment (no use_nodes needed, avoids deprecation warning)
- Document full CompositorNodeRLayers output socket list for Blender 5.0.1
- Clean up SOCKET_ALIASES to match confirmed socket names

1 files changed, 23 insertions, 5 deletions

diff --git a/cnn_v3/training/blender_export.py b/cnn_v3/training/blender_export.py
index f8ca9f6..290a35a 100644
--- a/cnn_v3/training/blender_export.py
+++ b/cnn_v3/training/blender_export.py
@@ -87,6 +87,7 @@ def _get_compositor_tree(scene):
             scene.compositing_node_group = bpy.data.node_groups.new(
                 name="Compositor", type="CompositorNodeTree"
             )
+        # In Blender 5.0+, assigning compositing_node_group activates compositing.
         return scene.compositing_node_group
     if hasattr(scene, "node_tree"):                        # Blender <= 4.x
         scene.use_nodes = True
@@ -136,6 +137,23 @@ def configure_scene(args):
     return _discard_dir
 
 
+# Full CompositorNodeRLayers output socket list (Blender 5.0.1, queried via console):
+#   ng = bpy.data.node_groups.new("T", "CompositorNodeTree")
+#   rl = ng.nodes.new("CompositorNodeRLayers")
+#   print([s.name for s in rl.outputs])
+#   bpy.data.node_groups.remove(ng)
+#
+#   ['Image', 'Alpha', 'Depth', 'Normal', 'UV', 'Vector', 'Position',
+#    'Deprecated', 'Deprecated',
+#    'Shadow', 'Ambient Occlusion',
+#    'Deprecated', 'Deprecated', 'Deprecated',
+#    'Object Index', 'Material Index', 'Mist', 'Emission', 'Environment',
+#    'Diffuse Direct', 'Diffuse Indirect', 'Diffuse Color',
+#    'Glossy Direct', 'Glossy Indirect', 'Glossy Color',
+#    'Transmission Direct', 'Transmission Indirect', 'Transmission Color',
+#    'Subsurface Direct', 'Subsurface Indirect', 'Subsurface Color']
+#
+# Mapping used here  (socket name → EXR layer name → Blender 5+ type):
 # (render-layer socket name, EXR layer name, Blender 5+ socket type)
 PASS_SOCKETS = [
     ("Image",        "Combined", "RGBA"),   # beauty / target
@@ -185,11 +203,11 @@ def configure_compositor(args):
 
     # Socket name aliases across Blender versions.
     SOCKET_ALIASES = {
-        "Shadow":       ["Shadow Catcher", "ShadowCatcher"],
-        "Diffuse Color":["DiffCol", "Diffuse"],
-        "Depth":        ["Z"],
-        "Object Index": ["IndexOB", "Object Index"],
-        "Alpha":        ["Alpha"],
+        "Shadow":        ["Shadow Catcher", "ShadowCatcher"],
+        "Diffuse Color": ["DiffCol", "Diffuse"],
+        "Depth":         ["Z"],
+        "Object Index":  ["IndexOB"],
+        "Alpha":         ["Alpha"],
     }
 
     # Link each render-layer output to the file output slot by name.